For those of you interested in designing and building a counter-flow

chiller here is a collection of related submissions to the Homebrew

Digest as of February 11, 1994.



Stephen Hansen

Homebrewer, Archivist



-------------------------------------------------------------------------------

 Stephen E. Hansen - hansen@sierra.Stanford.EDU  | "The church is near,

 Electrical Engineering Computer Facility        |  but the road is icy.

 Applied Electronics Laboratory, Room 218        |  The bar is far away,

 Stanford University, Stanford, CA 94305-4055    |  but I will walk carefully."

 Phone: +1-415-723-1058   Fax: +1-415-723-1294   |      -- Russian Proverb

-------------------------------------------------------------------------------



------------------------

HOMEBREW Digest #598                         Mon 18 March 1991



Date:    Fri, 15 Mar 91 13:19 EST

From: "Eric Roe" <KXR11@PSUVM.PSU.EDU>

Subject: Copper counterflow chillers



Regarding the use of copper tubing for wort chillers, I believe it's the

way to go.  As mentioned in other posts, copper has a much better heat

exchange rate that stainless steel.  Copper is also easy to work with.  If

you're making your own chiller, sweating connections is a fairly simple

procedure (not to mention kinda fun).  Stainless is hard to work with and

expensive.  Also, I don't believe you can solder stainless -- you either

have to weld it, use a compression fitting, or have the ends threaded.

Since copper has had quite a long history with brewing I see no problems in

using it.  I just wish I was lucky enough to have an eight gallon copper

kettle.



Also in HBD #597 Mike Zentner writes about using 1/4" OD tubing in his

chiller.  I made the same mistake (Greg Noonan must be nuts to recommend

such small diameter tubing).  Once I got the chiller assembled I decided to

test it by putting water through it.  The flow rate was incredibly slow.

I was using 22' of tubing and I calculated it would take over an hour for

5 gallons of water to flow through.  I didn't even think about the fact

wort would have a heavier gravity -- luckily I didn't try using it for my

beer.  After the disappointing results I took it apart and replaced the

1/4" OD tubing with 3/8" OD tubing.  The chiller worked much better with

the larger diameter tubing.  Now I can cool 5 gallons in about 20 minutes.

The flow rate would be even faster if I just made a minor modification to

my system.  I too would recommend using 3/8" OD tubing for making

counterflow chillers.



As for sterilizing, I fill the chiller with water and start a siphon.  Then

I put the wort-in end into a pot of boiling water and let this flow through

the chiller.  After the boiling water has flowed through I simply place the

wort-in end into the hot wort.  I turn on the counterflow cold water, the

siphon continues, and voila, cold wort starts coming out.  No muss, no

fuss; just make sure you don't interrupt the siphon at any of the above

stages.



                                       Eric

                              <kxr11@psuvm.psu.edu>



------------------------------

HOMEBREW Digest #612                         Wed 10 April 1991



Date: Wed, 10 Apr 91 02:31 EST

From: "ASK ME IF I CARE..." <V057P673@ubvmsc.cc.buffalo.edu>

Subject: Goofy wort chiller / advice?



In trying to get the most efficient chill possible, I rigged up this for a

wort chiller, but I have some minor questions to people using this.  Sorry if

this one has been hashed recently, but I picked up HBD with #574, haven't got

around to the archives, and feel I should contribute SOMETHING, dammit!



An immersion chiller should be more efficient with a constant flow of water

for heat exchange, plus, I had heard about people doing this.  What I did was

straighten out about a 20' length of copper tubing, and shove it inside about

23' of garden hose, starting at the end I cut off of the garden hose.  Then I

cut a hole in the garden hose about four feet down from the connector end of

the hose, pushed the end of the copper tube through, and made sure there was

about 6" sticking out of the end of the hose and also through the hole I cut.

Then I sealed the hole with RTV silicone, and coiled the whole mess back up

again. Here is a simplistic diagram:



<---3'----><--------------------20'--------------><-6"->

 __      \\  <-- copper tubing

|||\______\\_____________________________________

|||        \\                                    |------  <-- copper tubing

||| _____________________________________________|------

|||/

     ^-- garden hose



  The concept is, to run the syphon right from a lauter-tun (or strainer in a

bucket), through the copper tubing, while running cold water through the

garden hose to achieve a REAL fast chill.  Also, you can easily regulate the

output temperature simply by running more or less tap water through the hose.

I just got done inaugurating this device, and here are my observations:



1)  This thing does NOT need 20' of copper tubing.  Maybe an immersion cooler

might need that length, but I was barely running the tap water, and getting

wort out at ~60F.  I would think 8-10' would suffice.  I may split mine into

two wort chillers.



2)  My question:  Everybody I know who uses a device like this uses a

counterflow, that is, cold tap water running in an opposite direction to the

wort flow.  However, it just made intuitive sense to me to send both in the

same direction: The hottest wort will exchange the heat with the coldest water

and some sort of equilibrium will be reached by the time you reach the end

of the chiller.  Why would the chiller be more effective with counterflow?

Which method makes it easier to regulate temperature?  Enquiring minds just

GOTTA know!



thanks,

 -dr.d



------------------------------

HOMEBREW Digest #613                         Thu 11 April 1991



Date: Wed, 10 Apr 91 09:07:10 -0500

From: zentner@ecn.purdue.edu (Michael Zentner)

Subject: Re: Goofy wort chiller





"ASK ME IF I CARE..." aka dr. d aka V057P673@ubvmsc.cc.buffalo.edu writes:



> straighten out about a 20' length of copper tubing, and shove it inside about

> 23' of garden hose, starting at the end I cut off of the garden hose.  Then I

> cut a hole in the garden hose about four feet down from the connector end of

> the hose, pushed the end of the copper tube through, and made sure there was

> about 6" sticking out of the end of the hose and also through the hole I cut.

> Then I sealed the hole with RTV silicone, and coiled the whole mess back up

> again. Here is a simplistic diagram:

> 

> <---3'----><--------------------20'--------------><-6"->

 > __      \\  <-- copper tubing

> |||\______\\_____________________________________

> |||        \\                                    |------  <-- copper tubing

> ||| _____________________________________________|------

> |||/

     > ^-- garden hose





This has to be about the best character schematic I've seen :-).  For anyone

considering this design, another option in lieu of slicing into the hose is to

go out and buy one of those Y type hose adapters for each end of the garden

hose, so that the copper tubing can come out of one of the ports on the Y.

Regardless of the length of copper tubing you use, you'll probably have to

adjust the length of the garden hose (there are adapters for this again at any

hardware store).  Make the cut close to one of the ends, so you can already

have the Y screwed into the small piece of hose before joining the hose

together.  That way, you don't have to keep bending the copper in a circle to

screw on the Y.  Now, the other advantage of using a Y is that you no longer

need to use silicone sealer.  Get a hose nipple which has an ID larger than the

OD of the copper and which has hose thread, so it will screw onto the end of

the Y.  Then, a small 3" section of vinyl tubing that fits over the hose

nipple.  Get successively smaller pieces of vinly tubing that fit in the big

one concentrically until the ID of one matches the OD of your copper.  Secure

the whole thing with hose clamps and wa-la, you have a seal that would even

hold up to pressure (sometimes there is pressure in my chiller, since I have

installed a cooling water control valve at the outlet end).



> 1)  This thing does NOT need 20' of copper tubing.  Maybe an immersion cooler

> might need that length, but I was barely running the tap water, and getting

> wort out at ~60F.  I would think 8-10' would suffice.  I may split mine into

> two wort chillers.



While certainly true in some cases, this is NOT a good general rule.  The

length of tubing needed is greatly dependant on the diameter of the

copper being used.  I agree that for 1/4" OD copper, 10' is probably a good

guess, but I think you'll really have to rush the water through if you go with

3/8" OD.  Another variable is the ID of the garden hose.  The water flow rate

will be either faster or slower depending on this as well.  I don't doubt the

measured results of the author, but, as they say, mileage may vary, and I've

had experience now with two of these chillers.  Anyone wanting more detailed

descriptions of how I built mine, I can email them to you if you're really

interested.  There is no "right" way to build one.  My comment about diameters

and flow rates is based on the fact that your flow will most likely be laminar,

with well developed stream-lines.  When this is the case, the wort near the

edge of the copper tubing will lose heat quickly, but it must carry heat from

the center streamlines outward, which is not an instantaneous process in

laminar flow.  Same goes for the cooling water.  And as far as 1/4" tubing,

anyone thinking about it...think hard, because you may run into very long cool

times.



> 2)  My question:  Everybody I know who uses a device like this uses a

> counterflow, that is, cold tap water running in an opposite direction to the

> wort flow.  However, it just made intuitive sense to me to send both in the

> same direction: The hottest wort will exchange the heat with the coldest water> and some sort of equilibrium will be reached by the time you reach the end

> of the chiller.  Why would the chiller be more effective with counterflow?

> Which method makes it easier to regulate temperature?  Enquiring minds just

> GOTTA know!



If your outlet wort was at 60F, and you were using a mere trickle of cooling

water flow, your water must have been quite cold.  If you used parallel flow,

both in the same direction, then the cooling water cannot have exited at a

temperature above that of the wort, that is, as soon as the wort and water come

to the same temperature, the wort can be cooled no further.  Unless you have a

very fast flow rate, with such a system, the wort can never reach the

temperature of the water coming out of the tap.  However, with counter-flow,

the outlet wort is in "contact" with water at tap temperature, allowing the

wort to reach that temperature (again, depending on lengths, rates, etc).



Again, I am not trying to flame the original author as I'm sure what he/she

measured is fact, but building one of these things is nothing to be totally

blase' about.  You can end up wasting a bit of money with a failed attempt... I

know :-).  There are a lot of variables to think about.



Mike Zentner    zentner@ecn.purdue.edu



------------------------------

HOMEBREW Digest #620                         Mon 22 April 1991



Date: Fri, 19 Apr 1991 15:17 EST

From: BAUGHMANKR@CONRAD.APPSTATE.EDU

Subject: Sterilizing, cleaning copper in chillers



Darren Evans-Young hypothesized that the sterilization method he was

using for his counter-current wort chiller was the source of the

recent infection of his beer.  This is a subject dear to my heart

because I've been using (and selling) counter-current chillers for

about 8 years.  I had always stored my chillers with a mild solution

of clorox and water (1 teaspoon clorox per 1 gallon of water) in the

chiller between brewing sessions.  Since this worked for me-never an

infection in 8 years-I recommended the same to my BrewChiller

customers.



Then a friend in the plumbing business pointed out that they use

copper to sterilize swimming pools when they become real funky.  It

seems that copper has anti-bacterial properties.  Added to that

were the comments that the clorox caused little blue flakes to

form inside the copper tubing.  I've never worried about the blue

flakes because even though blue, they were sterile, and didn't seem to

affect the taste of my beer in any way.



Still blue flakes were a recurring comment and I began to consider

doing what Darren did, use boiling water to sterilize my chiller

instead of storing it with the clorox solution in the tubing.  And so

far so good, but I still do a quick 30 minute clorox soak prior to

brewing.  I'm a paranoid at heart. :-)



To insure that boiling water sterilizes the copper tubing, one must

siphon it through the tubing when the chiller is dry, that is, no water

in the "cooling chamber".  This must be done both after a brewing

session and before the next one.  So my question to Darren is: Is that

they way you handled your sterilization procedure?  If so, given what

my plumber friend said, I'd be surprised that the chiller is the

source of the infection.  Still I'm not a chemist and I'd be

interested in what the net has to say about all of this.



While we're on the subject:



A few digests back, someone pointed out that new copper has oils which

must be removed before first use of a chiller.  That's absolutely

correct.  I think they use silicone oils when extruding the copper

tubing.  I've always recommended doing a couple of clorox soaks

(1 Tablespoon clorox to 1 gallon of water, for 30 minutes) before using

copper chillers for the first time.  Following up or interspersing it

with a couple boiling hot water rinses is a good idea as well.



Cheers,



Kinney                                | Beer is my business and

baughmankr@conrad.appstate.edu        | I'm late for work.



------------------------------

HOMEBREW Digest #656                         Tue 11 June 1991



Date: Mon, 10 Jun 91 09:50:08 PDT

From: keng@ic.MENTORG.COM (Ken Giles)

Subject: Cleaning counter-flow chillers, try TSP



In HBD microsoft!larryba@cs.washington.edu says:



> The bummer with counterflow chillers is cleaning them out.  I have never

> figured out a satisfactory solution for the kitchen brewer.  Commercial

> microbrewers use nasty corrosive chemicals and lots of very hot water.



I've had good success with TriSodium Phosphate (TSP). TSP is not so corrosive tobe dangerous (gloves are recommended but I often get it on my arms with no ill

effects), but acts like a corrosive cleaner. I tried an experiment. After I 

rinsed and ran the usual bleach solution through my counter-flow chiller until

it ran clear, I ran a solution of TSP through, and it came out yellow and

eventually ran clear. The TSP was able to clean beyond the power of the bleach

solution alone. No real surprise. TSP is also great for dissolving the gunk out

of your blow-off hose.



TSP is available in the paint section of most hardware-type stores. It's used 

for preparing surfaces for painting. I've heard that some homebrew suppliers sell

a dry bleach/TSP combination called tri-chlor. I don't use this because I'm

typically only cleaning afterword (with TSP) or sanitizing beforehand (with

bleach).



Stay clean,



kg.



------------------------------

HOMEBREW Digest #656                         Tue 11 June 1991



Date: Mon, 10 Jun 1991 15:57 EST

From: BAUGHMANKR@CONRAD.APPSTATE.EDU

Subject: Sterilizing chillers; straining hops



Larry from Microsoft writes:



>The bummer with counterflow chillers is cleaning them out.  I have never

>figured out a satisfactory solution for the kitchen brewer.  Commercial

>microbrewers use nasty corrosive chemicals and lots of very hot water. I

>just rinse well after each use.  Before the next use I drain all the bleach

>solution used to sanitize my carboy through the chiller before draining the

>hot wort through it into the carboy.  I also toss the first pint of wort to

>make sure no bleach gets into my wort.  Probably draining a couple of gallons

>of boiling water through the chiller w/o chilling water would work as well

>as avoiding bleach.



Maybe commercial brewers use nasty corrosive chemicals but many 

brewpubs use boiling water or wort just like we do.  My technique is 

this:



Follow a chilling session with a gallon or so of boiling water through 

the coils after draining the chiller body of its water, to cut the 

malt sugars from the copper.  Usually I follow that up with some of the 

sterilant (I use 1 T. clorox per 1 gallon of water) that I've been 

using for that session, until the sterilant runs cool from the coil 

(since high temperatures destroy the disinfectant effects of clorox).  

Drain. Store dry.  



Prior to the next session of brewing, I will usually fill the chiller 

coils back up with the sterilant solution and let it sit for about 20 

minutes.  Drain.  When I begin the chill routine, I run the boiling hot 

wort through the chiller prior to filling the chiller body with water.  

The boiling hot wort will sterilize the coils for sure.  Toss the first 

few ounces of wort that comes through since some clorox will be in it.   

Let a quart or so of wort run through then return it to the boiler.  

Fill the chiller body with water and let 'er rip. 



The boiling wort through the coils is what really does the trick with 

this routine just like it does with immersion chillers.  So why do I 

still use the clorox solution?  It's simple.  It only takes a minute 

and I'm paranoid as hell! 





The most effective means for straining wort into the fermenter 

discussion has popped back up so here again is my pot-scrubber-in-a-

mesh-bag technique for filtering hops: 



I've never been a fan of pouring wort through a filter because filters 

clog and you're bound to pour at least some trub into the fermenter. 



Buy a copper wound pot scrubber and a fine mesh hop bag.  Also get a 

rather thick rubber band.  It also helps to have a copper pick-up tube 

if you're going to siphon hot wort into your fermenter.  If you're 

cooling it first, one of those plastic pick-up tubes will do the trick. 



Tie the pot scrubber around the bottom of the pick-up tube (the end 

that's going into the wort).  Then tie the fine mesh hop bag around 

that, in effect putting the pot scrubber in a bag.  (Oh, yes, "No see-

um netting" from a camping store works well, also.) 



Tie a small 1/4" overhand loop in one end of the rubber band.  Loop the 

other big end around and through the handle on your boiling pot.  Now 

slip the pick-up tube through the small end of the rubber band.   If 

you've tied the small loop small enough, the rubber band will grab the 

pick-up tube at whatever position you want.  Suspend the pick-up tube a 

couple of inches below the top level of the wort.  Start your siphon.  

The mesh bag/pot scrubber combo will effectively filter out all the hop 

leaves and particles.  By siphoning from the top level of the wort, 

you'll always be siphoning off the clearest portion of the wort.  As 

the level of the wort recedes, slowly inch the pick-up tube down 

accordingly, always keeping it an inch or two below the surface.  This 

technique will give you the cleanest possible run-off into the 

fermenter without clogging the siphon. 



Others have commented on the effect of whirlpooling the wort before 

starting the siphon, so I won't comment on that.



Cheers,



Kinney Baughman

baughmankr@conrad.appstate.edu

baughmankr@appstate.bitnet



------------------------------

HOMEBREW Digest #784                         Wed 18 December 1991



Date:         Tue, 17 Dec 91 08:23:04 EST

From: Tom Dimock <RGG@CORNELLC.cit.cornell.edu>

Subject:      Counterflow chiller size



Brian Capouch asks about sizes for the tubing in counterflow chillers...

Everyone I know who has used 1/4" tubing has regretted it.  They are just

too slow.  3/8" is better.  Now if you're into brewing fast, my

counterflow chiller is made using 25' of 1/2" tubing, and it will take

5 gallons of boiling wort down to 80 F in under five minutes.  My boiler

drains from the bottom - it might be difficult to start 1/2" as a

siphon.  For general guidelines, I'd say about 16-18' of 3/8".  Other

opinions?



------------------------------

HOMEBREW Digest #784                         Wed 18 December 1991



Date: Tue, 17 Dec 1991 11:48 EDT

From: BAUGHMANKR@CONRAD.APPSTATE.EDU

Subject: Chillers & Wet Mills



Brian asks:



>So I need to make a "quick-and-dirty' counterflow chiller.  My question

>is this: would 1/4" or 3/8" tubing make the better mousetrap?  Intuition

>tells me that the 1/4" would allow a much greater wort-to-coolant

>surface area, since there'd be more wort (relatively) on the outsides of

>the tubing than in the center.  That would be at the expense of

>throughput, but I'd rather have cool wort exiting slowly than hot wort

>exiting fast.



All the above intuitions are correct.  In fact I shared them when I 

designed the first version of the counter-flow chiller that I sell.  I 

chose 5/16" OD tubing for that model.  95% of the time it works fine.  

It's a little slower on the siphon (@ 30 minutes) but very efficient.  

However, it's too efficient for big, high gravity brews and the cold-

break is so pronounced that some people complained that it clogged the 

siphon.  Two years ago I switched to using 3/8" tubing.  With a strong 

water flow it works fine.  From my kitchen sink, I found that on the 

average the water exiting the chiller was about 10 degrees warmer than 

the smaller pipe.  If the wort coming out is too warm there are two 

things you can do.  (1)  Use a pinch clamp on the end of the exit hose 

to slow down the flow of wort.  (2) Try to connect to an outside 

faucet. The outside faucet at my house generates about three times the 

flow of water than does my kitchen sink.  No one has yet to complain 

of a clogged chiller with the larger tubing, BTW. 



The other thing to remember is to keep the water housing of the 

chiller as small as possible.  Heat exchangers are more efficient the 

more the coolant turns over.



...



Kinney Baughman                 |   Beer is my business and

baughmankr@conrad.appstate.edu  |   I'm late for work.





------------------------------

HOMEBREW Digest #784                         Wed 18 December 1991



Date: Tue, 17 Dec 91 10:49:49 CST

From: dyer@marble.rtsg.mot.com (Bill Dyer)

Subject: RE: Best size for counterflow chiller



In HBD #783 Brian says:



>So I need to make a "quick-and-dirty' counterflow chiller.  My question

>is this: would 1/4" or 3/8" tubing make the better mousetrap?  Intuition

>tells me that the 1/4" would allow a much greater wort-to-coolant

>surface area, since there'd be more wort (relatively) on the outsides of

>the tubing than in the center.  That would be at the expense of

>throughput, but I'd rather have cool wort exiting slowly than hot wort

>exiting fast.



>Is that logic good? 





Well, I thought it was good logic too but I was wrong.  I made a wort chiller

from 1/4" tubing immersed in ice water.  It worked great as far as cooling the 

wort goes, but it had several other problems, namely the throughput was way too

slow and on top of that it clogged.  It took about an hour to cool the first

3 or so gallons of a 5 gallon batch.  At that point the thing clogged and I had

to run some boiling water through to clean the clog and finish the cooling.  



A slow throughput is one thing but over an hour is too long for me.  I tried 

increasing the flow by raising the bucket (I sat it on top of the fridge)

but that didn't help much.  I am going to do one of two things to solve this

problem, either shorten the length of my current copper coil or go out and buy

some bigger stuff, I havn't decided yet which is better.  From feeling the wort

coller as it is now, the wort seemed to be cool about half way through the tubing

so I can probably cut down the length by about 1/3 (it is about 30' now I think).

This should increase the flow by 50% if I remember correctly. Of course to solve the

clogging problem, I may keep the length and go to the 3/8 tube.  Or as a third 

alternative I could cut the tube I have now in half a connect a Y to it.  This 

should double the flow.  Actually if I could remember all the fluid dynamics 

and thermodynamics I learned in college I could figure out exactly how long and how big my tube needs to be, but that is too much work so I will just guess.



Later,



Bill_____________________________________________________________________________

|  you'll think I'm dead, but I sail away   |Bill Dyer  (708) 632-7081      |

|  on a wave of mutilation                  | dyer@motcid.rtsg.mot.com      |

|                     -Pixies               | or  uunet!motcid!dyer         |



------------------------------

HOMEBREW Digest #908                         Tue 23 June 1992



Date: Mon, 22 Jun 1992 10:45 EDT

From: Kinney Baughman <BAUGHMANKR@CONRAD.APPSTATE.EDU>

Subject: Sterilizing counter-flow chillers







>:Wort Chillers.  OK, I am ready to take the step.  The immersion

>variety seems more practical from a sanitation standpoint.  I like the idea

>of keeping it clean, but sterilizing it just before use by inserting it into

>the boil for a few minutes before turning the water on.  



Oh, well.  Thought I'd do my part to dispel the ever-present notion 

that counter-flow chillers are impractical or difficult to keep sterile.  



When I finish using my counter flow chiller, I drain the chiller body 

of water and siphon boiling hot water through the coils to cut the 

malt sugars.  I then follow with some of my clorox sterilant solution 

and let it sit for about 30 minutes.  Drain and store.



Before using the chiller for the next brewing session, I fill it with 

sterilant again and let it sit for 30 minutes.  As if this isn't 

enough, before I actually start chilling the wort, I siphon the 

boiling hot wort through the copper coils until the wort runs boiling 

hot out the bottom.  (If boiling hot wort is good enough to sterilize 

immersion chillers, it's good enough to sterilize the counter-flow 

chillers or else I'm missing something.)  I then fill the chiller body 

with water, return the collected wort back to the boiler and proceed 

with the chilling procedure.  I've used counter flow chillers for 

eight years and have never had problems with contamination. 



Add to this the fact that copper is used to sterilize swimming pools 

because it has anti-bacterial properties (or so I'm told) and I've 

never worried an iota about contamination with my chiller.



The following points are somewhat technical but I might add that 

counter-flow chillers have several things in favor of them over 

immersion chillers.  (1) Shocking the wort cool produces better cold 

break.  (2) Since you can start siphoning immediately after finishing 

the boil, it's a time saver.  And finally (3) I'd argue that there is 

less chance of bacterial infection with the counter-flow chiller 

because any one drop of wort is going to go from boiling to pitching 

temperature in about 6 seconds. 



The down-side, of course, is that counter-flow chillers are both more 

difficult to make and, if you buy one, are more expensive. 



>From a purely technical point of view, I think counter-flow chillers 

win out.  But from an economic perspective, immersion chillers are the 

winner.



But whatever the case, use one or the other.  Wort-chillers are 

essential to any homebrewery.  



The AHA conference was indeed a blast.  As mentioned by others, it was 

great putting faces to email addresses.  There must have been ten 

times the number of online brewers at this conference compared to last 

year so there's no way I can make disparaging comments about those I 

met like I did last year.  So count your blessings. :-) 



Still I'd be remiss if I didn't say thanks to Martin Lodahl and Mike 

Sharpe for their outstanding lambic beer tasting and the information 

they provided to us regarding this most unusual of all beer styles.  I 

thought Mike's framboise was remarkably close to style.  Thank you, 

thank you, thank you for sharing that with us.  It was nectar of the 

gods as far as I was concerned and feel privileged to have gotten a 

chance to taste some of it.  



Cheers, ya'll.



Kinney Baughman                  |   Beer is my business and

baughmankr@conrad.appstate.edu   |   I'm late for work.





------------------------------

HOMEBREW Digest #944                         Mon 10 August 1992



Date: Thu, 6 Aug 1992 09:57:27 -0700 (PDT)

From: Paul dArmond <paulf@henson.cc.wwu.edu>

Subject: Re: Counter Flow Chillers <rocket science>



In HBD #941, on 3 Aug 92, Joe Rolfe asked about cutting down on water

usage and getting a lower output temperature from his counterflow chiller.



Here is the Rocket Science part.



My source is 'Cryogenic Engineering' by Russel B. Scott, D. Van Nostrand

Co. Inc.  1959.  Heat exchangers are important to cyogenics because they

form a very important part of the refrigerators used to liquify gases.  It

really is "rocket science", since you need lots of LOX and other gasses to

"make der rockets go up."  Other engineering books on steam power, oil

refining and thermo-hydrodynamics will provide similar information.



I'm not going to go into the mathematics, but try to explain everything as

empirically as possible.  Heat transfer equations are very heavy on

differential equations.  This stuff is not only hard to type without a

mathematical typesetting system, but it isn't very accessible to most people.



Joe's questions get right to the nub of the tradeoffs involved in heat

exchangers.  In the best of all worlds, you would use as little water as

possible, get the biggest temperature drop, and do it as quickly as

possible.  Unfortunately, all three of these factors work against at least

one of the others.  All of these factors are expressed in the

heat-transfer coefficient.



This coefficient is expressed as:



watts / [(cm**2)(deg K) in CGS   Watts per square centimeter-degree Kelvin



That's how much heat flows into the wall of the heat exchanger tube from

the liquid in contact with the tube wall.  The formulas assume that the

tube is straight, cylinderical, and smooth, and that the flow of the

liquid inside of it is turbulent (i.e. the tube is small enough that the

flow doesn't channel in the center.)  The factors that determine the heat

transfer coefficient are:



The specific heat of the fluid - This is a measure of heat (as opposed to

temperature) and empirically is measured by how much ice is melted by a given

mass at a given temperature.  Beer wort has a higher specific heat than

water.  The concept of specific heat supposedly came from Count Rumford

burning his mouth on some apple sauce.  The apple sauce was at the same

temperature as his tea which didn't burn.  He had just got his first

thermometer and was measuring everything in sight.



The mass velocity of the liquid: g / sec cm**2  How much mass is passing

through a given cross section each second.  For a given tubing size, this

is strictly determined by the available pressure and flow.  For your water

supply this is effectively limited by the maximum pressure available.



The thermal conductivity of the liquid.  Suprisingly, this is quite low

for most liquids.  Water is nearly an insulator, if all convection is

supressed.  I assume that wort has a low conductivity as well.  Things

like mercury and sodium metal have high conductivity.



The diameter of the tube.  For tubes that don't have a circular cross

section, this is replaced by the "hydraulic radius" which is defined as

the cross-sectional area divided by the wetted perimeter.



In designing a heat exchanger, there are only a few of these things that

we can influence.  We can alter the mass velocity by turning up or down

the flow on the faucet or altering the siphoning height.  We can pick the

diameter of the tube that we use.



Remember that we are looking at maximizing the heat-transfer coefficient

at one point of the tube in one direction (wort to tube or tube to water).

 We are only dealing with a slice, so that if the tranfer coefficient is

maximized, then we will get the most heat transfer out of a given length

of tubing.  The transfer coefficient will also set an upper limit on the

in/out temperature differential for a particular length.  If the tube was

infinitely long then the water out temp and the wort in temp would be

equal, and the wort out temp would be the same as the water in.  The

drawback with an infinitely long tube is that you would collapse both your

lungs before you could get the siphon started.  Also for an immersion type

cooler, it would not be possible to fit an infinite amount of tubing in

your brew pot, no matter how tightly you coiled it.



At any rate, you want the coefficient as high as you can get it.  It is

maximized when the tube is small (or the hydralic radius is small) and the

mass velocity is big.  This has several implications:



1) better heat transfer means using more water (faster flow).

2) Smaller tubes are better than bigger ones.  This makes sense, since

there is more surface area for the same amount of copper.  It is limited

by the ratio of cross sectional area to wall thickness.  The very small

tubes have a problem with this, in that their inside area is small

compared to the relative thickness of the wall.  Heat transfer is

inversely proportional to wall thickness, so there is a limit to how small

is small enough.



Well, we don't want to use more water, so that's out.  Joe is already

using 1/2" tubing in his cooler, so it would be rude to tell him to get

smaller tubing.  Wasteful too.  What we can do is decrease the hydralic

radius of his tube.  A circular cross-section has the lowest possible

ratio of area to perimeter.  This is why bubbles are round.  So how about

making the copper tubing not round.  There are some very high efficiency

florescent light tubes that have a rippled surface to increase the surface

to volume ratio.  The tubes look pinched, the pinches alternating 90

degrees from each other.  Maybe this could be done with a pair of

vice-grip plyers so the tube doesn't get pinched too much.



This high ratio of surface are to volume is why the breweries use flat

plate coolers, the transfer coefficient is quite high if you get away from

using tubes.  Multiple small tubes in parallel are also used for high

efficiency heat exchangers.



If you are building a cooler, here are some things to consider:



* for the same price, more feet of small tube are better than fewer feet

of big tube.



* The coefficients in a counterflow exchanger need to match.  The water

side will have to have a larger flow to match the lower specific heat of

water compared to wort.



* If you have a choice, thinner copper tube is better since heat flow is

equal to conductivity / thickness.



* When using an immersion chiller, stir the wort.  This will raise the

mass velocity on the wort side and improve the heat transfer.  Remember:

water and wort are poor conductors, heat transfer takes place by convection.



To get into the true "rocket science" of counterflow wort chiller design,

the specific heat, conductivity and viscosity of hot beer wort need to be

known.  Can anybody help?





------------------------------

HOMEBREW Digest #947                         Thu 13 August 1992



Date: Wed, 12 Aug 1992 22:20:14 -0700 (PDT)

From: Paul dArmond <paulf@henson.cc.wwu.edu>

Subject: RE: chillers



Michael Hall has written a very good paper on the calculations required

for a counter-flow type chiller.  I believe that Mike mentioned that he was

preparing to submit it to Zymurgy.  I searched the last two months of

archives for it, but came up dry.  John Palkovic kindly sent me a copy.

There is a rights reservation at the top, so I'm retroactively asking

Mike's permission.  My system's mailer keeps bouncing Mike's address.  I

believe I can reply if he contacts me.



That being said...  Mike's calculations suggest that a siphoning

counter-flow cooler would need to use a length over 30' if it was made of

1/2" copper tubing, but that 25 - 30' of 1/4" tubing would give a good

heat exchange efficiency.  The interesting part of Mike's results is that

there is a minimum length for any tubing diameter.  Using a longer length

does no harm, but you are buying more tube than you need.



An immersion cooler will have a higher velocity, since the water is being

driven by the mains pressure, rather than a siphon.  Since heat transfer

is proportional to velocity, the tubing lengths would presumably be

shorter.  In a parallel tube immersion cooler, smaller would be better.

The length of the cooler tubes would be determined by the number of tubes

in parallel, the I.D. of the chiller tubes, the water supply pressure and

the diameter of the supply line at the tap.  Most outdoor hose bibs are

1/2" pipe, while sinks are usually 3/8".



FWIW, my 25' x 3/8" immersion cooler has an outlet temp near the wort

temp, but only if I stir pretty fast.  Also pipe is measured by I.D, but

bendable tube is O.D.  This means that tubing sizes are bigger than the

fluid cross-section.  The difference is considerable for the smaller sizes.



Paul de Armond

paulf@henson.cc.wwu.edu







------------------------------

HOMEBREW Digest #1188                        Fri 23 July 1993



Date: Thu, 22 Jul 1993 08:40:03 -0400 (EDT)

From: Kinney Baughman <BAUGHMANKR@conrad.appstate.edu>

Subject: Siphoning through counterflow wort chillers



>From: Kevin V Martin <kmartin@magnus.acs.ohio-state.edu>

>Subject: Siphoning



>I recently made two changes to my brewing procedures.  I bought a wort chiller

>and used hop pellets for the first time.  After cooling my last batch of hot

>wort, I tried to syphon the cool wort.  I ended up clogging the syphon with

>trub and pellet rements.  Does anybody have a good way to syphon off the good

>stuff and leave the trub behind?  Thanks,



Time for my periodic posting on filter-siphoning:

- --------------------------------------------------------------------

Here is my pot-scrubber-in-a-mesh-bag technique for filtering hops:



Buy a copper wound pot scrubber and a fine mesh hop bag.  (Get a Chore

Boy.  They are made from 100% copper.  Also get a rather thick rubber 

band.  It also helps to have a copper pick-up tube if you're going to 

siphon hot wort into your fermenter.  If you're cooling it first, one 

of those plastic pick-up tubes will do the trick. 



Tie the pot scrubber around the bottom of the pick-up tube (the end 

that's going into the wort).  Then tie the fine mesh hop bag around 

that, in effect putting the pot scrubber in a bag.  (Oh, yes, "No see-

um netting" from a camping store works well, also.) 



Tie a small 1/4" overhand loop in one end of the rubber band.  Loop the 

other big end around and through the handle on your boiling pot.  Now 

slip the pick-up tube through the small end of the rubber band.   If 

you've tied the small loop small enough, the rubber band will grab the 

pick-up tube at whatever position you want.  Suspend the pick-up tube a 

couple of inches below the top level of the wort.  Start your siphon.  



Note: By siphoning from the top level of the wort, you'll always be 

siphoning off the clearest portion of the wort.  As the level of the wort 

recedes, slowly inch the pick-up tube down accordingly, always keeping it 

an inch or two below the surface.  This technique will give you the 

cleanest possible run-off into the fermenter without clogging the siphon. 

(There are a couple of gizmos on the market now [one is made by Fermentech] 

that clip to the pickup tube, attache to the rim of the brewpot and suspend 

the pickup tube off the bottom of the pot.)     The mesh bag/pot scrubber 

combo will effectively filter out all the hop leaves and particles.  But 

the mesh can still clog and I consider it a flourish to the technique and 

not essential.  Should it clog, the easiest thing to do is to just take it 

off and resume your siphon with the pot scrubber alone.  An alternative is 

to raise the brewpot which increases the flow rate of the siphon. 



It's also a good idea to stir the wort, just after the end of the

boil, to create a whirlpool action in the kettle.  This will cause the

precipitate matter to settle out into a cone in the bottom of the

vessel.  At the end of the siphon you'll find a "moat" of wort around

the cone and be able to siphon off almost all of the cleared wort.



Cheers!



- -------------------------------------------------------------------------

  Kinney Baughman                     |       Beer is my business and

  baughmankr@conrad.appstate.edu      |       I'm late for work.

- -------------------------------------------------------------------------







------------------------------

HOMEBREW Digest #1206                        Wed 18 August 1993



Date: Mon, 16 Aug 93 11:51:41 -0700

From: Drew Lynch <drew@chronologic.com>

Subject: YACFWCD (Yet another counter flow wort chiller design)





  After modifying my immersion chiller to be a "coil in a bucket -o-

cold water" chiller, I finally seem to have gotten it right.



        Drew's Counterflow Wort Chiller Design



Parts list:

        50' 5/8" id garden hose

        50' 3/8" od soft copper refridgeration tubing

        6 ea 1.5" long pieces of 1/2" copper pipe

        2 ea copper "T"s to fit above pipe

        2 ea copper end caps for above pipe

        4 hose clamps

        plastic zip ties



Tools Needed:

        sharp knife or clippers

        propane torch, solder and flux

        standard screwdriver

        power drill, 1/8" bit & 3/8" bit



1) Cut off each end of the garden hose, leaving about 8" attached to

   each "hose end" 



2) Insert the 6 pieces of copper pipe into the 6 ends of the 2 copper

   tees, and solder in place.



3) Drill a 1/8" hole in the end of each copper end cap.



4) Enlarge these holes to 3/8"



5) attach one end cap to each enlarged "T" so that you can look

   through the "T" and see light through the 3/8" hole in the end cap.



6) straighten the 50' of copper tubing, and feed through the garden hose.



7) slip a hose clamp over each end of the garden hose.



8) slip the copper "T" assembly over the end of the copper tubing, and

   into the garden hose. Attach with clamp.



9)  Solder the copper tubing to the "T" assembly where it passes

    through the hole in the end cap.



10) Using the 2 remaining hose clamps, attach the hose end remnants to

    the "other" end of the "T" assembly.



       copper T   ______________________________________  copper T     

  end+-----------+ clamp       Garden Hose        clamp +-----------+end

===============<<<<==copper=tubing=<<<=wort=flow=direction=<<<============

  cap+--+     +--+______________________________________+--+     +--+cap

        |     |                                            |     |

        +     +                                            +     +

       | clamp |                                          | clamp |

       |       |                                          |       |

      Hose end in                                        Hose end out



11) Coil this using your favorite round object as a form. I used my

    old 5 gallon brewpot. Zip tie the coils together.



  I attached 3/8" id plastic tubing to each end of the chiller.  For

the "in" end, I attached a 3/8" od copper racking cane.  I hose

clamped a copper Chore Boy scrubber to the end of the racking cane, to

filter out hop particles.



  To sanitize, I siphon iodophor solution through the chiller into the

carboy. To start the siphon, put a female garden hose to 3/8" hose

barb fitting on the "out" end and attach it to a water source, Place

the "racking cane" into a bucket filled with sanitizer. Then run the

water until all the air is removed from the system, disconnect the

water source, and place the "out end" lower than the "in end" immersed

in sanitizer.  I use this same method to start the siphon from the hot

wort (remember not to blow bubbles into the hot wort though).



  This design works very well.  I was able to drop boiling wort to

within 5 degrees F of the tap water temperature.  I found three

drawbacks: 1) The flow is very slow. It took about 20 minutes to

siphon 5 gallons through the system. 2) a fair amount of wort is left

in the tubing then the siphon quits. 3) a fair amount of wort is left

amongst the hops in the bottom of the brew kettle.  I have a small

food grade pump which I may attach to the outflow of the chiller next

time I use it, which should solve #1 & #2 and help #3.



  I may also add another, bare copper coil between the outflow of the

CF chiller and the carboy.  This coil will be immersed in a small ice

bucket.  This will minimize the amount of ice needed, and get that

final, desireable drop in temperature.





                              Drew Lynch

                Chronologic Simulation, Los Altos, Ca.

                          (415)965-3312 x18

                         drew@chronologic.com



------------------------------

HOMEBREW Digest #1255                        Tue 26 October 1993



Date: Fri, 22 Oct 93 01:09:00 +0300

From: ari.jarmala@mpoli.fi (Ari Jarmala)

Subject: Slow CF chiller





drose@husc.harvard.edu writes about slow CF wort chillers:



HO>I bought 50ft of garden hose (a lot

HO>cheaper than tygon tubing), 50 ft of 1/4" copper tubing, and built

HO>a 40 ft chiller (10 feet of the hose going to the connecting lines).



1/4" tube is very thin. Try larger diameter tube. The gain:



* the cross section area of the tube is the _square_ of the

diameter

* the flow is the cross section area times the speed of wort in the tube

* the resistance to flow is reduced by increasing diameters =>

faster flow



Increase the diameter by a factor of 2 and you get about 6 to 8

times faster volume flow. Maintain the length of the chiller.



The other possibility is to increase the driving force: increase

the height difference.



 - Ari J{rm{l{









------------------------------

HOMEBREW Digest #1258                        Fri 29 October 1993



Date: Tue, 26 Oct 1993 10:54:14 -0400 (EDT)

From: "Robert H. Reed" <rhreed@icdc.delcoelect.com>

Subject: CF Chiller Effects on Hop Character





Norm Pyle writes:



> With the counter-flow chiller the wort and hops remain near 100C the entire

> time the wort is being chilled.  From experience I know the kettle is still

> extremely hot 20 minutes after turning off the flame.  I would bet that

> finishing hops act more like flavoring hops and that flavoring hops act more

> like bittering hops with a counter-flow.  Can anyone verify these assumptions? <snip> 

> I may alter my procedure a little bit to compensate for this.  I haven't yet

> decided how.  Suggestions?



I noticed a similar change in late hop character when I changed to using a CF

chiller: I found that to obtain the same hop flavor and aroma, I had to add 

*more* hops *later* in the process as compared to my previous process that

used an immersion chiller.  One technique that I have found useful is to add

hops *during* the runoff.  After my boil is complete, I stir the wort vigorouslyand wait 15 min for the trub and hops to settle.  During the runoff - about 

25 min for 5.5 gal - I typically add whole hops in one or two additions.  This

has improved the intensity of my late hop character.  I use a slotted pick-up

tube in the boiler to avoid clogging the chiller.



I feel the CF chiller has pros and cons:  I get a much better cold break with

my CF unit using well water.  My wort exit temp is ~55-60F. Another

benefit is that, given that my chiller and settling tank are disinfected, there

is very little risk of infection because the wort in my boiler is still above

160F at the end of runoff.  On the downside, one must deal with the cold break

in the fermentor and the late hop character is decreased in the 30-40 min.

the wort remains in the boiler.



Rob Reed



------------------------------

HOMEBREW Digest #1260                        Mon 01 November 1993



Date: Wed, 27 Oct 93 11:37:01 -0700

From: "Stephen E. Hansen" <hansen@Sierra.Stanford.EDU>

Subject: YACFC, Yet Another Counter Flow Chiller.



     Last week I decided to build a counterflow chiller (I had been

using an immersion unit previously).  I debated whether to use a garden

hose or a piece of large diameter PVC pipe to enclose the copper tubing

and went with the hose for simplicity's sake.  I have seen one or two

commercial versions of counterflow chillers that use something that

looks like coiled copper in a section of PVC pipe but I couldn't find

end caps that looked like they would work without more work than I

wanted to put in.



    What I did was buy a 50' 5/8" ID garden hose and 50' of 3/8" OD

copper tubing.  In addition I bought two hose end replacement connectors,

one male and one female, and two of those Y hose connectors with the

the built in ball shutoff on each leg of the Y.



    I took the hose and cut it in two with 30' left on the piece with

the male connector.  I slid the copper tubing through the hose from the

cut-off end until about 12" stuck through past the other end.  Then I

cut the copper tubing leaving about 12" on both ends.  The male hose

repair connector went on the cut end.  Getting the last ten feet or so

of tubing through the hose took some elbow grease but persistence paid

off.



    Next I took the Y adapters and slid the copper tubing up the trunk

of the Y and out through one of the legs until I could screw the Y onto

the hose end.  This was a bit tricky but if you counter-twist the hose

before mating the ends it works pretty well.  The hard part was getting

the copper tubing past the ball valves in the Y.  One fit perfectly but

the other had to be drilled out with a 3/8" bit.  The fit of the copper

tubing in the Y is essentially watertight on one of the connectors but

the other leaks a bit.  I'll probably put some silicone sealer in that

one.  Once the Y connectors were on tight I just recoiled hose to about

a 12" diameter and loosely tied the coils together.



     As for the female replacement connector.  That goes on the cut off

end of the 20' piece. giving me a short hose with two female connectors

on each end.  You need this to connect to the inlet of the chiller.



     The remaining copper got turned into a siphon cane and an aerator.

The aerator was build from the description by Spencer Thomas in HBD 1081

and it works great.



     The next day I made an IPAR (an IPA with Rye) and the chiller

worked like a champ.  Compared to my immersion chiller this is MUCH

easier and faster.  The wort outflow wasn't much warmer, if any, than

the tap water inflow.  The tap water flow rate is your temperature

adjustment in this setup and I was able to use a fairly slow flow of

water.  Obviously, with my current water temperature I could have

gotten away with a shorter chiller but the water temp will warm up a

bit in the summer.



     I siphoned the hot wort off the hops and hot break material in the

kettle and into a plastic bucket with a tap valve at the bottom.  The

copper scruber in a mesh bag tied to the end of the copper siphon wand

did a good job of keeping things clear.  I took the bucket full of hot

wort and set it on top of the washing machine.  The chiller sat just

below it on a stool, a 5 gallon carboy sat on the floor.  Plastic

tubing went from the outlet of the tap valve to the inlet of the

chiller.  More plastic tubing went from the outflow to the aerator wand

stuck in the carboy.



Stephen Hansen

Homebrewer, Archivist



=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

 Stephen E. Hansen - hansen@sierra.Stanford.EDU | "The church is near,

 Electrical Engineering Computer Facility       |  but the road is icy.

 Applied Electronics Laboratory, Room 218       |  The bar is far away,

 Stanford University, Stanford, CA 94305-4055   |  but I will walk carefully."

 Phone: +1-415-723-1058   Fax: +1-415-723-1294  |      -- Russian Proverb

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-



------------------------------

HOMEBREW Digest #1263                        Thu 04 November 1993



Date: Tue, 2 Nov 1993 8:36:29 -0800 (PST)

From: Jim Cave <CAVE@PSC.ORG>

Subject: Counterflow chillers





        There has been considerable debate recently on the relative merits of

immersion vs. counterflow chillers.  While I do not intend to try and convince

others to switch to the counterflow design, it is the one that I use for the 

following reasons:



        1) About 50% of the beers (all-grain) that I brew are lagers.  I prefer

very cold ferments to these beers (45 F).  For much of the year, I can get my

beer close to this temperature with this design.  During the summer months I

use an additional coil (after the counter current) which runs through an ice 

bath.  This drops the beer an additional 10 F.  This rapid drop in temperature

makes for remarkable cold breaks.



        2) Much of the trub falls out in the kettle.  I have a hop-back and a

second screen in at the outlet-valve to prevent the occassional errant hop from

entering the chiller.  I give the wort a quick stir to generate a whirl-pool.

The counter-current flows into glass carboys.  I then rack off the trub and

into glass carboys (Yes I rack off the trub; the breweries I have talked to 

estimate that they remore 95% or more of their trub prior to ferment).



        3) The unchilled beer remains well above 160F and is therefore sterile.

Gravity checks can be rapidly made at the exit of the chiller and gently re-

introduced to the boiler without fear of contamination.



        4) When 2/3's of the wort remains in the kettle, I throw in hops for

aroma (hot soak).  This gives excellent aroma.  A hop-back in-line with the 

chiller would be a better way to go but I have't come up with a rugged design

yet.

        5) With my boils, I always seem to end up with a gravity 4 or 5 points

higher than target (and correspondingly less volume).  I have recently come up

with a gentle way of adjusting gravity.  I fire up the sparge tank and boil 

water.  This is introduced with a tube into the boiler with the beer

(when the beer has nearly all gone through the chiller). This gently washes

the hops and trub of fermentable extract.



        One disadvantage that I see with the counter current chiller is that

the Irish moss addition is less effective, as it doesn't really enter the

collecting carboys. Consequently, the beer in the collecting carboys takes

longer to drop bright than it otherwise would in the boiler.  However, as I

mentioned, trub is also settled and filtered out in the boiler.



        I guess you pays your money and takes your chances!!



        Jim Cave 684-684-8081 "I brew.....I am" 



------------------------------



