Chiller Ideas

I am moving up to a keggle from my aluminum Turkey Fryer pot, and need to do something for a chiller. I am planning on putting a false bottom w/ weldless fitting into the keggle. My thought is to get a 50' Length of copper line (3/8") and coil it up in a spare cooler, and then fill the cooler with heavily salted ice water. Once the boil is complete, kill the heat and run the water through the coil into my now retired aluminum pot, sanitized of course. I am thinking I will probably still use this pot for heating my mash/sparge water anyway, which would sanitize it without having to go through any extra steps. To keep the water in the cooler moving, I would just drop in a spare bait tank pump with no hoses attached, should keep it swirling quite nicely. To control the speed of flow, I would just put an adjustable ball valve on the output side of the coper coil. My reasoning for going this route is that in SC in the summer, our water temp gets up there making a normal immersion chiller pretty ineffective without using a pre-chiller, which this would get around.

Sounds good in principal. I'm guessing you would need to move the wort rather slowly and have some method to add more ice as the process proceeds.

arturo7 said:

Sounds good in principal. I'm guessing you would need to move the wort rather slowly and have some method to add more ice as the process proceeds.

Click to expand...

with salted water, the initial temperature should be pretty cold, and with enough water volume in the cooler I don't think it would be too hard to keep things in check.. To control the flow I would just use a ball valve on the output side of the chiller, and adjust it to the ideal setting. This would also make sanitizing the inside of the coil easy, just run starsan through it out of a bottling bucket until it comes out, and close it off and let it sit for 20 minutes or so. My only real reservation is how to clean out any solids that may stick to the inside of it. I am fairly sure that a good soaking in oxyclean followed by a relatively high flow rinse would do the trick.

Sounds like a plan to me.

One thing though, people underestimate HOW much salt you need to make a difference. Say you have, oh, 15 quarts of ice and 15 quarts of water in your cooler. 15 quarts of water is 14.2 liters. 1 pound of salt is 7.76 moles. You get 15.52 moles of sodium+chloride ions when you dissolve it, and 15.52/14.2 = 1.09. The freezing point depression constant for water is 1.9, so you will get 1.9*1.09 = 2.07*C freezing point depression per pound of salt.

This means that with a pound of salt, you get a water/ice mixture that freezes at 28.24*F.

3.7*F difference in freezing point isn't much, and won't help a great deal when cooling your wort, (your end wort temp should be around 70*F, so we're talking about 4/70, or about a 6% improvement in heat transfer). You'll probably want 3-5 lbs salt to make any appreciable difference.

Short version: Just use ice water, or start buying salt in bulk.

You'll need about 40lbs of ice and you'll have to constantly stir the icewater to get the warm water away from the coils.

Two words....Counterflo chiller

just looking at the physics of it, I don't see how a counterflow would be any improvement over this setup. By having the bait tank pump in the cooler, all of the liquid will remain constantly stirred. Throw in a few frozen water balloons, and a couple of big scoops of water softener salt, and the water should get down to around 25 degrees. Short of pre-chilling the water and pumping it through on a counterflow chiller, this looks like it would be far superior to a counterflow using 70 degree + tap water.

The physics Bobby is talking about relate to the amount of ice you need to melt to chill 5 or 10 gallons of wort.

Some more physics here: Wort from 100 to 20 degrees C is an 80 degree difference. Heat capacity of water is 4.19 J/g/K, so to take 5 gallons of wort down it's 4.19*(5 gallons * 3790 grams/gallon)*(80 degrees C) = 6352 kJ.

To get 6352 kJ purely by melting ice, you need 6352 / 334 = 19 kg of ice. That's around 42 lbs. For a 10 gallon batch, 84 lbs. Of course, your ice will be below room temp, but you won't be starting with 0 degree water either...so whatever, either way, it's quite a lot of ice required, (I could do all the math, but that's boring...). When The Pol did this, he found he needed around 40 lbs.

A counterflo has the advantage of using warmer water to cool down the hottest wort, and colder water to cool down the cooler wort, (because your chilling water runs counter to the wort). It's more efficient this way. What would probably work best, with the least amount of hassle for you and least amount of buying ice and salt, would be a counterflow, with the inlet chilling water first running through a small prechiller in your ice cooler.

I use a pond pump in a cooler and recirculate through the CFC less waist water that way. My suggestion was that you already have almost all of the components in your plan minus a hose and some misc fittings. You can also go from 50' of 3/8" down to 25'. YMMV.

Here in AZ the temp of our ground water during the summer can get into the 90's pretty easy, so made an immersion chiller that uses tap to bring the wort down to around 100*F then recirculates through a bucket of ice water for the last 20*F.

On my primary test I cooled 5 gallons of 115*F water to near 80*F with around 10lbs of ice.

With your setup I'd definitely try and find a way to use tap water for at least the first part of your cooling cycle before switching to ice.

The ice thing shouldn't be too big of a deal, full cooler from work (free) plus about a dozen frozen water balloons. Truth be known, this is probably big time overkill, just trying to be able to do a full boil, and cool it efficiently, without having to buy another pot. I am shooting for 6 gallons finished, which I am guessing will put me starting at around 9 gallons total starting volume. All of the immersion chillers I have seen look like they would be horribly inefficient in a keggle below half full, and most won't work at all without major modification.

Does anyone know of one specifically made for a keggle that the majority of the coils sit lower in the pot?