SS Brewtech Unitank carbing equipment

[TGFB]

Steeping (my awesome pun..) up my game to carbonate in a unitank. The question is if anyone has done this without using a $1K glycol chilling system. My plan to reach carb temp. was to use a (good) cooler with ice and pump through while carb. (hopefully hitting the target temp of upper 30's). Has anyone tried this?

Then, saw a cheap freezer, so thought of rigging a up cooling coil in the freezer with a glycol mix, and running that through the immersion chiller, and that would get me down to carb.temps. The max pressure for the tank is only 15 psi. My plan is to bottle the beer after carbin ( Having kegs around the house was not conducive to responsible imbibing! )

Has anyone tried this? any ideas that wont break the bank?

Really dont want a large freezer running all the time, or starting and shutting down every month or so, starting up a small freezer (1.1 cu ft) isnt so bad.

Any experience would be appreciated. Thanks!

 

[Bobby_M]

You will not be able to maintain beer temps in the 30's with an air to liquid method of cooling glycol. Without getting that beer ice cold, the bottling process is not going to work. Stick with bottle conditioning.

 

[TGFB]

Thank you for the reply. Are you saying that it needs to be a closed system to use glycol and cool the beer to bottling temps? i.e. penguin chiller?
Nothing to motivate imagination and inspiration then being told it cant be done.

 

[Bobby_M]

I'm exposed to a lot of people that have tried a lot of things. In the case of a tank sitting in 25F air (in a freezer), the first obstacle is heat transfer. The incoming warm glycol doesn't have a lot of surface area to shed heat into the air. The next way to thing of it, erase the air transfer... Fill up a chest freezer directly with the gycol. That's when you find out the compressor on a chest freezer isn't up to the task either. Saying either of these methods don't work will find the people that have had some level of success. Sure, there is probably a fermenter in a certain ambient temp that can be cooled to fermentation temps. It's not going to work for what you are specifically trying to do.

 

[TGFB]

So the returning warm glycol is the overpowering variable that will stress the cooling ability of a standard freezer or freezer fridge combo.
The fermentor heat sinks, beer temp. and ambient air will elevate temps beyond the ability of air cooling in the fridge or freezer. Makes sense. the recycled coolant will not have enough time to cool to satisfactory temperatures before returning to the fermentor chiller because air transfer is inefficient in the freezer.
So one way to mitigate this is to increase surface area.
Also it would be more efficient just remove the glycol system entirely, and put the unitank in a freezer and turn it on when it is time to carbonate. at some point it will get down to 40F.
seems easier to transfer to a keg, carbonate, then bottle.

 

[Vale71]

Fill up a chest freezer directly with the gycol. That's when you find out the compressor on a chest freezer isn't up to the task either.

That's not necessarily true. If the freezer is large enough it will most definitely have enough power to cool a single tank all the way to lagering temperatures, possibly even two depending on fermentor size and ambient temperature. The downside is you'll need a lot of glycol to fill such a large freezer almost to the brim to provide adequate contact with the freezer walls where the cooling coils are.

 

[Bobby_M]

That's not necessarily true. If the freezer is large enough it will most definitely have enough power to cool a single tank all the way to lagering temperatures, possibly even two depending on fermentor size and ambient temperature. The downside is you'll need a lot of glycol to fill such a large freezer almost to the brim to provide adequate contact with the freezer walls where the cooling coils are.

It's not necessarily true but practically and empirically true. I put 19 gallons of glycol mixture into a 7 cubic foot chest freezer and the temp of the whole bath rose to 40F while trying to hold one insulated 1/2BBL unitank at 36. It is true that it was not full to the top so it was missing contact with half the walls. It's cost prohibitive to fill it.

 

[speavler]

My first cooling system consisted of a bucket of glycol in a freezer with a pump. I could get into the low 40's while cooling a 7 gallon chronical BME. You might be able to do it if you have low ambient temps, a very large bucket of glycol and/or have the chilling coils in direct contact with the glycol. Air cooling isn't efficient enough.

 

[Vale71]

It's not necessarily true but practically and empirically true. I put 19 gallons of glycol mixture into a 7 cubic foot chest freezer and the temp of the whole bath rose to 40F while trying to hold one insulated 1/2BBL unitank at 36. It is true that it was not full to the top so it was missing contact with half the walls. It's cost prohibitive to fill it.

On the other hand I've had great success with a 5 cubic feet chest freezer and a 14 gal Unitank. I can cool it until the beer starts freezing on the coil at about 1.0-1.5°C and the freezer still only runs intermittently. Of course I did look for the freezer with the best insulation and the most powerful cooling unit in that size group. The overall cost including 25 liters of propylene glycol amounted to less than a third of what the SSB glycol chiller would have cost me. Since I never plan on owning more than one fermenter the greater cooling power of the chiller would have just amounted to wasted money for me.
One added advantage of having such a huge heat sink (80 liters of glycol mix that can be pre-cooled down to -10°C) is that I can cool the wort to a somewhat higher temperature than what I intend to pitch at saving time and water and then quickly cool it, literally in a matter of minutes, to pitching temp.

 

[Bobby_M]

Yeah, it sounds to me like there are a dozen variables to setups like this. Some of which only matter a little but everyone's mileage will vary. If you only plan to use one fermenter, there is almost no reason not to stuff the whole thing into a fridge. I hate the condensation that exposed cooled FVs make.

 

[TGFB]

Thanks for all the input, this has been very helpful.
The idea of surface area got me thinking. Thought about filling the entire 3 cuft. freezer with copper coil leading to a glycol bath (but that still has the air exchange inefficiency) Get the initial temperature of the fermentor down to the 50's with an ice bath, then switching and pumping through the mini freezer to start carbonation. Hoping it would be able to overcome and maintain the 40/sub 40 temp.
Then found a glycol build with a disassembled a.c. unit and a cooler. The ac fin & coil system would dramatically increase surface area for heat exchange, and bypassing the thermostat, will make it run until the desired temp is reached (hopefully). And also the heat sink Vale has mentioned. The larger(glycol pool), the cooler, the better.
It is a 5000BTU unit, and it is only 5-6 gallons.
A quick estimate of BTU (1F/1pound water) needed would be 42 pounds of beer 30F, 1251 BTU. that is with out figuring out all the heat sinks and inefficiency. gives me a fudge factor of about 75%. Not bad odds...

 

[TGFB]

It has been a while, but going through the old posts, figured I would put this pic. up.
Its worked out. I usually only go to about 38* but wanted to try going lower. This is today and 12 psi. After doing this a couple times,
found this video.