Counterflow - What could we possibly be doing wrong?

[jwbeard]

So we bought an all-copper convoluted CFC from Midwest Brewing Supplies, and are getting dreadful performance from it. Even at a trickle from the kettle, with the valve barely open, we're hard-pressed to get 72 degrees (much less the low 60s that all the CFC threads seem to report). Hose is on full, and the runoff feels cold (implying incomplete thermal transfer). Turning down the hose raises the temperature, turning up the wort does too (I thought maybe it was flowing too slowly to properly take advantage of the convolution).

Hose-in is connected at the bottom of the CFC next to the wort-out; hose-out is at the top next to the wort-in.

Today we even put my old immersion cooler inline into a bucket of ice with the runoff going to the CFC. It got us another degree or two but no appreciable increase...

I'm worried about DMS, since it's taking 90 minutes to empty a 10 gallon batch (ridiculous).



Flow rate is deceptive above... Looks like its actually doing something interesting. It's not.

Please, tell me I'm being an idiot and am missing something obvious... This is ridiculous.

 

[Yooper]

I'm surprised with a prechiller that it didn't cool fast. What is your tap water temperature (right out of the tap)?

Edit- I misunderstood and you don't have a prechiller. If you ground water is warm at this time of year, a prechiller is a good idea. That would be your IC in a bucket of ice water for your tap water before it hits the CFC.

 

[bucfanmike]

are you running the water and wort in opposite directions? If you are running them in the same direction you wont see much cooling, just like you are describing

 

[bucfanmike]

i see the way you have it standing up, water out is at the bottom, if that is also where you have the wort exiting it wont work.

 

[airving]

I'll ask the easy question: What's your water temp? The farther below your target temp it is, the quicker it will be to cool. I recently had mine going full speed (water from hose wide open and kettle through pump through CFC back to kettle) and got from boiling to ~160 in 25 minutes. But my water isn't very cold...

 

[jwbeard]

The wort goes in the top and out the bottom; the hose water goes in the bottom and exits the top. Current water temp is 60...

And yes, there's a pre chiller- hose goes to IM, which was in a bucket of ice; then from the IM to the CFC.

 

[Golddiggie]

If you have a pump, you could run the wort through the chiller, back into the kettle (at full speed) to do a recirculation chill. Do that until it gets closer to your target temperature, and then run it one last time through the CFC into primary.

I do this with my plate chiller. I can get 7 gallons to pitching temperature, in the middle of summer, in about 10-15 minutes. That's with a smaller diameter hose feeding the chill water to the plate chiller (I'll be getting some 3/4" ID hose before I use it again). I do the recirculation for 5-8 minutes (depends on the season, and ground water temperatures) and then switch over to running into primary. I then use gravity to feed the chiller, with occasional hits from the pump. The gravity feed method does extend the chill time a bit, but it's better in the warmer months here. During the cooler/colder months, my chill time is about half of what it is in the summer.

BTW, what's the ID of the water hose you're using??

 

[Ryush806]

This may sound like a stupid question....have you tried collecting any of the wort after it's been chilled and used a thermometer to check the temp? The reason I ask is because it's possible at that flow rate that the actually thermometer side of your thrumometer (is that what it's called?) is not actually being touched by the wort. It could be that it's just measuring the air getting up into the device.

I prefer to use a valve after the thermometer to control flow instead of at the kettle because that way it ensures that the CFC and thermometer stay 100% full. This way you get an accurate temp reading and use all of your available heat transfer surface area to cool your wort.

 

[jwbeard]

If you have a pump, you could run the wort through the chiller, back into the kettle (at full speed) to do a recirculation chill. Do that until it gets closer to your target temperature, and then run it one last time through the CFC into primary.

Pump is one of the next purchases. CFC and mash tun put a dent in the available funds...

BTW, what's the ID of the water hose you're using??

3/8" lining for the hose-in, I believe. It's from the tubing I had connected to my IM, which is 3/8 OD copper.

 

[jwbeard]

This may sound like a stupid question....have you tried collecting any of the wort after it's been chilled and used a thermometer to check the temp? The reason I ask is because it's possible at that flow rate that the actually thermometer side of your thrumometer (is that what it's called?) is not actually being touched by the wort. It could be that it's just measuring the air getting up into the device.

Not a stupid question at all - its actually a bit hotter, so you're probably correct about the measurement issue. The collected wort measured at 76 degrees in the carboy using the thermometer attached to the outside.

 

[Ryush806]

I think I would try using a hose clamp or your fingers to apply some back pressure (like a valve on the outlet would do) to make sure the CFC stays full during operation. If only a little trickle is coming out of the kettle and there's no back pressure then only the very bottom part of the copper tubing will be full of wort. You'd have ~75% of your heat transfer surface not doing anything.

Also, does your kettle have a dip tube? If so there might be some air trapped in the line that can't get out. You can either use an autovent or just bleed a very small amount of wort out of the kettle first before you attach the tubing to make sure the dip tube is cleared of air.

 

[Golddiggie]

Pump is one of the next purchases. CFC and mash tun put a dent in the available funds...



3/8" lining for the hose-in, I believe. It's from the tubing I had connected to my IM, which is 3/8 OD copper.

Get some garden hoses for the water going in. Best with 5/8" or 3/4" ID there (larger ID, more GPM flow). I've been using either 1/2" or 5/8" ID hoses for my chiller, but I'll be upgrading soon (to 3/4" ID). If you put the smaller ID on the our end of the chill water, that should give the water more loiter time, to increase the cooling capability.

Before I got the pump, I tried using gravity to feed the wort to chill. As the seasons became warmer, it was harder and harder to get a decent chill time. That's when I picked up the pump and started using my current method. Granted we don't get as hot out here, for as long, as you do in CA, the ground water temp can get up there. It can take a lot of effort to get the wort chilled to where we want it due to this.

 

[PowellsPub]

This is the other guy brewing with jwbeard today...

I think you may be right about air in the CFC and us only getting a portion of the heat transfer. I'm surprised nobody seems to have that problem. I'll look around and see if we can find an inline ball valve to attach to the end of the CFC.

Another question: Anyone connected the output of CFC to the input of immersion cooler in a bucket of ice water to drop the wort the last 10 degrees or so? Our problem using a prechiller is that we didn't get enough heat transfer to cool the water going into the CFC very much unless we had our water flow rate turned down too far..... I was thinking if I sanitize the inside of the immersion cooler, we could run the wort through it to cool a bit more than the CFC and keep our water running at a decent flow rate.

 

[Ryush806]

If you put the smaller ID on the our end of the chill water, that should give the water more loiter time, to increase the cooling capability.

I wouldn't do this. You get more "use" out of each gallon of water but the more water you have going through your chiller the better it will chill the wort. Heat transfer is dependent on the temperature difference between the two fluids. If you are sending more water through, it will always be colder and you will get better heat transfer. I don't mean to sound like a no it all but I'm a chemical engineer and deal with industrial heat exchangers everyday. High flow of the cooling medium is essential to efficient heat transfer.

Another question: Anyone connected the output of CFC to the input of immersion cooler in a bucket of ice water to drop the wort the last 10 degrees or so? Our problem using a prechiller is that we didn't get enough heat transfer to cool the water going into the CFC very much unless we had our water flow rate turned down too far..... I was thinking if I sanitize the inside of the immersion cooler, we could run the wort through it to cool a bit more than the CFC and keep our water running at a decent flow rate.

I think this would work. The only problem would be potentially losing a little bit of wort inside the immersion chiller. You'd have a big temp difference between your wort and 60 F water in the CFC and get a good temp difference between cooled wort and ice water in the immersion chiller. Swirling the immersion chiller will help with heat transfer, too.

 

[rmaloney86]

The way you are set up I'd say that there is a good chance your thrumometer isn't getting an accurate reading.

 

[Golddiggie]

I was talking about having 3/4" in, and maybe 5/8" out. I wouldn't make the difference any more than that. I'll probably not do that when I change over to 3/4" ID hoses for my plate chiller. I'd rather have same rate in and out in my system.

The size difference was recommended by a friend that has a good deal of engineering (real world experience too) knowledge. I'd still rather go same size in and out. But, I would also increase the hose ID size to something higher. With that, you could do away with the pre-chiller (made from the old IC). You could also use a pond pump in a bucket of iced water to feed the chiller. Just make sure you have a large enough bucket, and enough ice, to get things chilled right. Not sure if a 5 gallon bucket would be enough for this. You might need a 10-15 gallon drum.

 

[Dgonza9]

Just trying to clarify, are you taking 90 minutes to get down to 72 degrees? Or are you trying to get into the low 60's?

 

[makomachine]

You can only go as low as your ground water temp without a pre chiller....which is ~80F in my neck of the woods. 60F in California? You must live in the mountains somewhere.

 

[catalanotte]

So we bought an all-copper convoluted CFC from Midwest Brewing Supplies, and are getting dreadful performance from it. Even at a trickle from the kettle, with the valve barely open, we're hard-pressed to get 72 degrees (much less the low 60s that all the CFC threads seem to report). Hose is on full, and the runoff feels cold (implying incomplete thermal transfer). Turning down the hose raises the temperature, turning up the wort does too (I thought maybe it was flowing too slowly to properly take advantage of the convolution).

Hose-in is connected at the bottom of the CFC next to the wort-out; hose-out is at the top next to the wort-in.

Today we even put my old immersion cooler inline into a bucket of ice with the runoff going to the CFC. It got us another degree or two but no appreciable increase...

I'm worried about DMS, since it's taking 90 minutes to empty a 10 gallon batch (ridiculous).

View attachment 69222

Flow rate is deceptive above... Looks like its actually doing something interesting. It's not.

Please, tell me I'm being an idiot and am missing something obvious... This is ridiculous.

I read this whole thread and a bunch others as I am having the same problem. Did you find a solution?