Automated all in one systems versus a conventional stand... convince me ?

[brewman !]

I agree that a 2 stage chiller is the way to go. Regards, don't circulate the ice water used in the 2nd stage. Pump it through very slowly. The principle is the same whether its done in a single or dual stage system.

 

[orangehero]

Wouldn't the ideal be to stop recirculating as soon as the ice has all melted?

 

[brewman !]

Wouldn't the ideal be to stop recirculating as soon as the ice has all melted?

Nope.

Lets say your wort is sitting at 55F after chilling with tap water.

If you recirculate until the ice has melted, you've taken your cooling water from 32F solid-liquid slurry to 32F liquid.

If you pump the ice water once through, you've taken your cooling water from 32F solid-liquid slurry to 52ishF liquid.

See the difference ?

The chilling water is much warmer if you pump it once through. For every BTU you heat the chilling water, you are cooling the wort by the same 1 BTU. Thus if your CFC warms the chilling water to a higher temp by pumping the chilling water once through, it must be making the wort much cooler. And, in fact, it does.

 

[schematix]

I agree that a 2 stage chiller is the way to go. Regards, don't circulate the ice water used in the 2nd stage. Pump it through very slowly. The principle is the same whether its done in a single or dual stage system.

OK so we can agree that cooling in stage 1 (212F -> 80-120F*) using tap water is the right thing to do. Without question it makes the 2nd stage using ice (a relatively expensive and hard to come by commodity in the quantities required here) much easier if you pre-chill with an essentially limitless resource.

Can you explain your logic behind not recirculating your ice water chill loop in the 2nd stage? In my experience i just can't store enough ice cold water to take my wort down to lager temps after the first stage. Recirculating let's me reclaim chill water that is still cold (colder than fresh tap water).

*depends on your ground water temp and tolerance for sending water down the drain

 

[brewman !]

OK so we can agree that cooling in stage 1 (212F -> 80-120F*) using tap water is the right thing to do. Without question it makes the 2nd stage using ice (a relatively expensive and hard to come by commodity in the quantities required here) much easier if you pre-chill with an essentially limitless resource.

FWIW, what is the temperature of your tap water if your wort is only cooling to 80-120F ?

Can you explain your logic behind not recirculating your ice water chill loop in the 2nd stage? In my experience i just can't store enough ice cold water to take my wort down to lager temps after the first stage. Recirculating let's me reclaim chill water that is still cold (colder than fresh tap water).

If you circulate the wort once through and you circulate the ice water once through and you do so at a speed that you don't run out of either, theoretically with a counter chiller 5 gallons of ice water will go from ice water to 80F while 5 gallons of wort goes from 80F to ice cold. In the real world it will probably take 8 gallons. This assumes that both liquids are going once through, that you have an efficient chiller and you flow the liquids through at a speed that allows the heat exchange to occur. You know this is happening when the outlet temp of the ice water is high and the outlet temp of the wort is low. Ideally you will have thermometers on both outlets to monitor this while running the chill process.

I don't know how to explain the thermodynamics. One liquid goes from ice to hot and the other liquid goes from hot to ice. If you start recirculating either liquid then the temperature differentials get messed up and the ice water doesn't get hot and the hot wort doesn't get cool.

As soon as you recirc the ice water, its temp goes up. You can no longer get the wort ice cold.

As soon as you recirc the wort, you aren't heating the ice water up as much and you aren't getting full thermodynamic value from it.

I suggest you hook your CF up to 2 taps and play around with it. Put a very hot tap on the wort side and a very cold tap on the hot side. Play around with flow rates and watch the exit temps.

Like I said, it should only take 8 gallons of ice water to get 5 gallons of wort really cold if you are doing things right.

The other thing to watch is the directions. The fluids need to flow in opposite directions, thus the term "counter flow".

 

[orangehero]

Nope.

Lets say your wort is sitting at 55F after chilling with tap water.

If you recirculate until the ice has melted, you've taken your cooling water from 32F solid-liquid slurry to 32F liquid.

If you pump the ice water once through, you've taken your cooling water from 32F solid-liquid slurry to 52ishF liquid.

See the difference ?

The chilling water is much warmer if you pump it once through. For every BTU you heat the chilling water, you are cooling the wort by the same 1 BTU. Thus if your CFC warms the chilling water to a higher temp by pumping the chilling water once through, it must be making the wort much cooler. And, in fact, it does.

Your explanation doesn't make sense. The chilling water coming back from the heat exchanger, right out of the heat exchanger, has absorbed the heat from the wort and thus will be at a higher temperature, regardless of whether you dump it back into the icewater container or use it to water your lawn.

I'm by no means an expert in thermodynamics, but as I understand it you would need much less water and ice as the heat coming back would be absorbed by the melting ice. Depending on how fast you recirculate the temp of the ice water won't increase until you've melted all of the ice. You can think of it as another water heat exhanger feeding coolant to your wort heat exhanger.

 

[brewman !]

I'll leave you guys figure it out.

 

[schematix]

FWIW, what is the temperature of your tap water if your wort is only cooling to 80-120F ?

It varies seasonally. This February I measured it at a chilly 40F. With that water I was able to get 10G to 48F in the ferm with 0 ice (2 stage, but 2nd stage was direct to ferms)! This is the temp I want to be at for lagers (most of my brews). Two Septembers ago I measured the tap water at 80F (highest it got). The reason I stop my first stage at 80-120F is because the efficiency is so poor after that point that it takes me another 10 minutes (and another 25-35G of water), to drop the wort another 20-30 degrees. As you have alluded to, temperature differential is key here.

If you circulate the wort once through and you circulate the ice water once through and you do so at a speed that you don't run out of either, theoretically with a counter chiller 5 gallons of ice water will go from ice water to 80F while 5 gallons of wort goes from 80F to ice cold. In the real world it will probably take 8 gallons. This assumes that both liquids are going once through, that you have an efficient chiller and you flow the liquids through at a speed that allows the heat exchange to occur. You know this is happening when the outlet temp of the ice water is high and the outlet temp of the wort is low. Ideally you will have thermometers on both outlets to monitor this while running the chill process.

I don't know how to explain the thermodynamics.

Here's a good link that describes the thermodynamics: http://web.mit.edu/16.unified/www/FALL/thermodynamics/notes/node131.html

I don't disagree with your statement that what you're doing is most efficient in terms of heat transfer, but in my experience it requires a significant quantity of ice water to make it work. By recirculating the ice water you allow yourself to not need as big of a tank to hold all that ice water, or even have to control your flows precisely enough such that you don't run out.

I'm going to study up on that webpage a little more and see if i can put some real numbers to this. Should be enlightening.

 

[brewman !]

It varies seasonally. This February I measured it at a chilly 40F. With that water I was able to get 10G to 48F in the ferm with 0 ice (2 stage, but 2nd stage was direct to ferms)! This is the temp I want to be at for lagers (most of my brews). Two Septembers ago I measured the tap water at 80F (highest it got). The reason I stop my first stage at 80-120F is because the efficiency is so poor after that point that it takes me another 10 minutes (and another 25-35G of water), to drop the wort another 20-30 degrees. As you have alluded to, temperature differential is key here.

Something is wrong here. With a CFC, you pump the wort through once. You pump it slow enough that it comes out at a temp near the incoming coolant temp. You don't recirculate the wort back to the kettle. It goes through once, period, end of story.

I don't disagree with your statement that what you're doing is most efficient in terms of heat transfer, but in my experience it requires a significant quantity of ice water to make it work.

That is because you are recirculating the ice water !!!!

By recirculating the ice water you allow yourself to not need as big of a tank to hold all that ice water, or even have to control your flows precisely enough such that you don't run out.

Believe me, 8 gallons of ice water will make 5 gallons of wort very cold. You are pumping the wort through too fast for it to transfer heat to the chilling liquid.

Good luck.

I'm going to study up on that webpage a little more and see if i can put some real numbers to this. Should be enlightening.[/QUOTE]

 

[schematix]

Something is wrong here. With a CFC, you pump the wort through once. You pump it slow enough that it comes out at a temp near the incoming coolant temp. You don't recirculate the wort back to the kettle. It goes through once, period, end of story.

I do in fact recirculate the wort back to the kettle. This has several advantages outside the scope of this discussion. Do you have any idea how much ice water it would take to cool 10G of boiling wort down to 50F in a single pass? There is little difference between tap water and ice water when your delta T is high. Might as well take advantage of cheap tap water for cooling until your delta T gets small so you don't need as much ice.

 

[schematix]

Wouldn't the ideal be to stop recirculating as soon as the ice has all melted?

Ideal would be to not run out of ice....

If you did then it would depend upon how much more water you needed to cool the wort.

If you needed more water than was remaining, you'd want to recirc until your coolant tank hit the same as the ground water temp, then divert that to the drain. Once you run out of water then you'd want to go back to tap water.

 

[brewman !]

Do you have any idea how much ice water it would take to cool 10G of boiling wort down to 50F in a single pass?

Yes I do. Theoretically, 10 gallons. In real life, 15 gallons.

You aren't getting this.

*ANY* CFC, if the fluids are pumped through slow enough, will transfer nearly 100% of the heat differential from one fluid to the other.

So the wort will go from near boiling to near ice and the ice water will go from near freezing to near boiling. In one pass.

Once this occurs, there is no use recirculating the fluids. Once the cooling water is near boiling, its no longer useful. Discard it. And once the wort is chilled near the coolng water, why dump it back into the boiling wort ? Its at the desired temp ! Put it in the fermentor.

The key is that both fluids go through ONCE ! And they go through slowly enough that the transfer occurs. If you go faster than the heat can transfer, then all bets are off. If you recirculate either of the fluids, all bets are off.

Don't believe me ? Hook your CFC up to 2 taps, one hot and one cold and play with the flows.

I once burnt my hand on the cooling water coming out of a CFC. In winter with 40F tap water, its easy to get 45F wort in one pass. Just adjust the flow rates.

BTW, the hot break is tremendous when you do this.

 

[orangehero]

You want to the coolant to be flowing as fast as possible.

 

[JKoravos]

The problem I always had with my CFC was I had to flow the wort really slow, even when I was blasting cold tap water through it, to get the wort temp down to pitch temp in one pass.

I don't know about what you guys are using, but mine wasn't very efficient.

Also, you should keep recircing ice water until the ice is gone, because you should be able to keep the ice bucket temp near freezing as long as there is ice in there. Usually we want to get our wort to 45-65F, so really as long as the water is less than that and you can get your flows right you can keep recircing.

 

[brewman !]

Good luck with your brewing endevors.

 

[schematix]

Yes I do. Theoretically, 10 gallons. In real life, 15 gallons.

I can't buffer 15G of ice water, nor can i make and store enough ice to make 15G of ice water.

You aren't getting this.

I completely get what you are saying, and I'm not saying that that you are wrong. I don't think you get what I'm saying. I'm saying it's much faster and uses far less ice to chill my way.

*ANY* CFC, if the fluids are pumped through slow enough, will transfer nearly 100% of the heat differential from one fluid to the other.

So the wort will go from near boiling to near ice and the ice water will go from near freezing to near boiling. In one pass.

True. But i'm not waiting an hour to chill 10G of beer, especially while its sitting near boiling. One of the many benefits of the wort recirc is that you chill the entire batch below DMS levels very rapidly. Also easy to perform a hop steep.

Once this occurs, there is no use recirculating the fluids. Once the cooling water is near boiling, its no longer useful. Discard it. And once the wort is chilled near the coolng water, why dump it back into the boiling wort ? Its at the desired temp ! Put it in the fermentor.

You're missing my original point here with using tap water first, THEN ice water. I only recirculate ice water once my wort is sufficiently cool such that the warmed cooling water IS STILL COLD. The process is overall faster if you have both flows as fast as possible. At max flow its not ready for the fermenter in 1-pass.

Don't believe me ? Hook your CFC up to 2 taps, one hot and one cold and play with the flows.

I once burnt my hand on the cooling water coming out of a CFC. In winter with 40F tap water, its easy to get 45F wort in one pass. Just adjust the flow rates.

Yep and that hot water goes right down the drain because its worthless. However, that ice water is still cold after a pass.

BTW, the hot break is tremendous when you do this.

You mean cold break.... yep and mine mostly stays in the kettle.

 

[killroy77]

Biab only results in cloudy beer if you fail to take other measures to clairify. Whirfloc , whirlpool, cold crash and you get crystal clear beer every time. Efficiency and a few small extra steps is the main difference.

 

[brewman !]

I'm out of this discussion. Good luck.

 

[JKoravos]

True. But i'm not waiting an hour to chill 10G of beer, especially while its sitting near boiling. One of the many benefits of the wort recirc is that you chill the entire batch below DMS levels very rapidly. Also easy to perform a hop steep.

Recirculating back to the kettle was one of my better brewing breakthroughs when it come to beer flavor. I noticed an immediate change in hop flavor and aroma when I went from single pass CFC to recirculating IC.