Wort Chillers, SS vs Copper

[edco76]

So I'm probably about to order a wort chiller. I looked at Morebeer, because they have free shipping, and I have some Paypal money available.

They have a SS for 59.99 and a copper for 69.99

What are the real pros and cons between the 2?

I have a 10g aluminum pot that I will be doing 5g full boil extracts in, if that matters. And I'll be outside.

 

[dkevinb]

Copper is much, much better at conducting heat, so it will chill more efficiently. You can make your own copper IWC very easily, but copper is not cheap. Still, you'll save a few bucks.

My ugly homemade 20' chiller:

 

[sandyeggoxj]

I would highly recommend going with something that has a 1/2" diameter. If you want stainless then stainlessbrewing.com and buy the 1/2"x50' for a hundred bucks.

 

[doug293cz]

I have a 25 ft x 3/8" (OD) SS IC, and it works quite well. It is also more tolerant of rough handling than a copper coil. The water coming out the exit gets quite hot, so heat is transferring adequately.

IC's are much more complicated to analyze than counterflow chillers. One of the most important things for improving the efficiency of an IC is to have a high level of wort agitation. Otherwise, the wort next to the coil cools rapidly, and heat flow from the bulk of the wort into the IC slows down drastically. Overcoming this effect is the reason for moving the coil around in the wort continuously, or stirring/recirculating the wort. Poor homogenization of wort temps while chilling can have a bigger effect on cooling time and efficiency than the metal of the coil does.

I'm not aware of any well controlled studies of otherwise identical IC's made of Cu vs. SS. I would like to see some if they exist. It would also be interesting to see studies of 3/8" vs 1/2" IC's. A well controlled study would not involve the use of manual agitation of the IC or wort, and require controlled water temps and flow rates.

Brew on

 

[Rev2010]

Copper is far more thermally conductive than stainless steel. That's why wort chillers have for the most part always been copper. Here's two quick Google links showing the thermal conductivity of copper vs. stainless steel:

http://www.tibtech.com/conductivity.php

http://www.engineeringtoolbox.com/thermal-conductivity-metals-d_858.html

And on this Wikipedia page: "Copper has a thermal conductivity of 231 Btu/(hr-ft-F). This is higher than all other metals except silver, a precious metal. Copper has a 60% better thermal conductivity rating than aluminium and a 3,000% better rating than stainless steel" http://en.wikipedia.org/wiki/Copper_in_heat_exchangers - also one of the reasons you see Stainless steel pots with an aluminum sandwich layer in the bottom as aluminum is also a far better thermal conductor than steel.

Now, I'm not a metal scientist at all, so I'll say straight up I have no scientific basis in materials but it seems quite obvious Copper is far more conductive thermally than steel. Sure steel will work fine and still cool your wort down, it just won't chill it as fast as copper of equal length and diameter will. And as mentioned above, circulate your wort for the quickest possible chill. I simply use a sterilized spoon to stir the wort. I used to stir the wort with my chiller but eventually I wound up loosening the worm clamp on one end without realizing it and had it come loose and start spraying water. So word to the wise... don't use your wort chiller to stir the wort use a spoon.


Rev.

 

[jbb3]

Copper all the way. My DIY chiller cost me about $45 bucks. 3/8"x50' copper refrigeration tubing, a garden hose fitting, a few stainless steel worm clamps and I'm all set.

Whatever you do, don't buy a 25' chiller. It will cool the wort eventually but will not perform like you want it to and you won't be happy with it in the end.

 

[NewJersey]

I started with a 25' copper IC and then bought a 50' SS IC. I have the copper one feed the SS one for like 5 minutes and then immerse the copper one in ice water. From boil to pitching in ab i ut 10 minutes. Debate copper vs SS thermal conductivity all you want. The SS is stronger and easier to clean.
I also pretty much stir the whole time btw

 

[Rev2010]

I use a 25' IC and have no problems with the time to chill. In winter when the ground water is very cold I chill to my pitching temp, say 60F, in 8 minutes. I've timed it. Fall and spring it takes 11 minutes average. Works for me.


Rev.

 

[Eugenio]

I remember reading somewhere that the weakest link in thermal conductivity is the capacity of wort to transmit heat, so that even tho copper is far better than SS at tranmitting heat, it all still moves at the capacity wort can handle. So Copper wouldnt be that significantly better than SS. I have to look it up, not sure where I saw it, or if I did saw it.

Anyways, I have a copper CFC, but I will be switching to SS soon. Just bought one, all I have to do is put it to use. Im doing this just because its stronger, doesnt tarnish as bad, and requires less maintenance.

 

[Wreck99]

Would the SS one from stainlessbrewing cover an entire 15-gal or 20-gal kettle? Looking to upgrade my kettle soon and I can say my 25' copper IWC takes forever to chill my 13-gal kettle...mostly because of surface area covered I think. There's alot of room between it and the walls of my wide kettle.

 

[dkevinb]

What are you guys doing to your wort chillers that they require so much cleaning and maintenance? I hose mine off and drop it into the kettle 10 minutes before the end of the boil to sanitize it. After chilling I drop it into the rope tote I use to collect the really hot chilling water, hose it off again and hang it up to dry. It's always clean and shiny. It's not a real high-maintenance piece of equipment.

 

[Rev2010]

What are you guys doing to your wort chillers that they require so much cleaning and maintenance?

Same here, I don't "clean" mine at all ever in over three years use. On brew day I sanitize the chiller in a bucket of StarSan before use. After I'm done with brew day I put the chiller in my bathtub and throughly spray it clean with my hand held shower head. I then dunk it a few times in the StarSan bucket just to make sure every area is rinsed, then I spray it down again to rinse off the StarSan. I let it air dry in another bucket. Been working fine for me.


Rev.

 

[sandyeggoxj]

Would the SS one from stainlessbrewing cover an entire 15-gal or 20-gal kettle? Looking to upgrade my kettle soon and I can say my 25' copper IWC takes forever to chill my 13-gal kettle...mostly because of surface area covered I think. There's alot of room between it and the walls of my wide kettle.

When you start getting into bigger batches don't be afraid of plate heat exchangers. Highly effective and not bad to clean.

 

[jbb3]

No special cleaning here (copper IC). As soon as I pull the IC out of the wort, I hose it down to get the crub off before it start to dry. Turn it upside down to let it drain and put it away when it's dry.

Next batch, as my wort is heating up, I'll give it a quick wipe-down with a sponge and a little soap and water, rinse it real good and set it aside. With 15 minutes left in the boil, I plunk it in and let the boiling wort sanitize it.

BTW, Can you make do with a 25' chiller? Yes, of course. But if you can swing it, you'll be much happier with a 50' chiller. Then if you start to move up to 10 gal batch size, you'l have it covered. Right now, I do 6.5 gallon batches as my fermenter has 7.9 gal capacity.

 

[doug293cz]

I remember reading somewhere that the weakest link in thermal conductivity is the capacity of wort to transmit heat, so that even tho copper is far better than SS at tranmitting heat, it all still moves at the capacity wort can handle. So Copper wouldnt be that significantly better than SS. I have to look it up, not sure where I saw it, or if I did saw it.

You're on the right track. Heat transfer systems are fairly complicated arrangements of serial and parallel heat paths, but all the separate parallel paths are usually made up of several serial elements. Heat flow systems are often modeled as electrical networks of resistors because the math is equivalent. If you have a bunch of resistors in series, the most limiting resistor is the highest value one. If you change one of the lower value resistors, even if you drop the value to zero, the overall path resistance doesn't change nearly as much percentage wise as the single changed resister did.

In a heat exchanger, the fluid tube material makes up only one of the resistors in a series path, and it may not be the biggest, most important resistor. So improving the thermal conductivity of the tube material may not have as big an effect as expected.

Brew on

 

[schematix]

Definitely copper. The cost is comparable to stainless, it's easier to work with, it's almost as corrosion resistant, it's a significantly better conductor than stainless. Only drawback to copper is that it doesn't match all the pretty stainless typically found in our home breweries.

For an immersion chiller, I'd go 50' of 1/2" copper, with a whirlpool.

Regardless of cooling mechanism, keeping the wort moving and mixed will dramatically improve cooling times because it maximizes temperature gradients.

 

[rhys333]

Glad I found this thread. I'd like to build a chiller this weekend for my new pot, but I'm debating on 25 or 50 feet. From the comments above, it seems people have success with both sizes. I do have really cold water, especially in winter, and I plan to stick with 5 and 6 gallon batches.

Folks with 25' copper chillers... how long does it take you to chill, assuming you whirlpool or agitate the chiller to maximize efficiency?

Thanks All.

 

[dkevinb]

Glad I found this thread. I'd like to build a chiller this weekend for my new pot, but I'm debating on 25 or 50 feet. From the comments above, it seems people have success with both sizes. I do have really cold water, especially in winter, and I plan to stick with 5 and 6 gallon batches.

Folks with 25' copper chillers... how long does it take you to chill, assuming you whirlpool or agitate the chiller to maximize efficiency?

Thanks All.

It takes about half an hour with constant agitation for me. My tap water temps are usually pretty high, though, living in SoCal. During the summer I use a pond pump to recirculate ice water after chilling to 100-120F.

If and when I do it over I'm going with a 50' chiller.

 

[Rootski]

For the record, I have both a SS and a copper IC. I pay very close attention while I'm chilling so I've made lots of observations.

The main thing is regardless of the metal used, if the wort isn't flowing, it's not cooling as quickly as it could be. You'd have to be constantly stirring without stopping to have any chance of noticing a difference between the same size chillers of the two different metals and even then I highly doubt you'd notice a difference of thermal conductivity over a distance of 1/32 of an inch of metal. Start water flowing and put your hand in the outflow water. It should begin to feel cool. Now stir the wort, and it gets hot. Stop stirring and see how long it takes to get back to cool. It'll probably only be a few seconds. That has WAY more to do with rapid chilling than the material used. Don't let thermal conductivity of the base metal sell you on one or the other.

I think the main reason copper has always been used is because it's easier to work with and easier to DIY.

 

[rhys333]

I think the main reason copper has always been used is because it's easier to work with and easier to DIY.

Whether SS or copper, this little tool will help with the DIY portion. It makes those tricky tight bends at the bottom of the coil and the two ends. Cheap too, and you don't need to use fittings or solder.

http://www.princessauto.com/en/detail/tubing-bender/A-p2910677e

 

[jbb3]

I think that's one thing we can all agree on. Keep the wort moving to maximize chilling performance!

 

[doug293cz]

For the record, I have both a SS and a copper IC. I pay very close attention while I'm chilling so I've made lots of observations.

The main thing is regardless of the metal used, if the wort isn't flowing, it's not cooling as quickly as it could be. You'd have to be constantly stirring without stopping to have any chance of noticing a difference between the same size chillers of the two different metals and even then I highly doubt you'd notice a difference of thermal conductivity over a distance of 1/32 of an inch of metal. Start water flowing and put your hand in the outflow water. It should begin to feel cool. Now stir the wort, and it gets hot. Stop stirring and see how long it takes to get back to cool. It'll probably only be a few seconds. That has WAY more to do with rapid chilling than the material used. Don't let thermal conductivity of the base metal sell you on one or the other.

I think the main reason copper has always been used is because it's easier to work with and easier to DIY.

This fits in with what was said here:

I remember reading somewhere that the weakest link in thermal conductivity is the capacity of wort to transmit heat, so that even tho copper is far better than SS at tranmitting heat, it all still moves at the capacity wort can handle. So Copper wouldnt be that significantly better than SS. I have to look it up, not sure where I saw it, or if I did saw it.

Brew on