Crash cooling issue

[OnTheFlyBrewing]

Equipment:

• 1/5 hp Ss Brewtech glycol chiller
• 7 gallon Ss Brewtech unitank

My first brew has gone fairly well, but I'm at an impasse. After three weeks in the unitank, I want to crash cool the beer to drop the yeast/proteins from suspension. However, the lowest I can get the beer is about 38ºF.

Here is what I've done to check my equipment.

• Verified temperature of glycol.
• Verified temperature reading of unitank temp controller which commands the pumping of the glycol.

I have read how this is an issue with lower ABV beers (mine is in the Centennial Ale recipe from this forum around 4%).

• I have tried bringing up the glycol temp to 33ºF so that there should be no freezing on the chiller coil.
• I have tried to step down the temperature.

Nothing seems to work. It always stalls out around 38-40ºF.

I want to bottle this, but I don't know where to go from here.

Any other ideas?

Thanks,
Greg

 

[CodeSection]

Obviously, ambient temperature and insulation will have an affect. With that said, the SSB 1/5 HP Glycol Chiller has one of the lowest BTUs...it is only rated 1450 BTU. At least is has a larger reservoir than most.

When reading the unit's quick start up guide on page 4, it indicates you can only set the glycol reservoir temperature between 28F - 32F. Since there is roughly a 10F delta between the glycol temperature and what you can crash to, the best you can crash to is around 38F-42F.

https://cdn.shopify.com/s/files/1/0...ler_quick_start_guide.pdf?5712410923823710477

Thus, your unit is working according to its specs. You might try more insulation or a blanket around your fermenter, but I'm afraid you will not get much better.

Where did you buy the unit? Does the company of a 60 day return policy (like MoreBeer) that will allow you to return it for a full refund less shipping?

Good luck!

 

[Vale71]

You can set the temperature lower but all this will get you is ice forming on the coils and the result will be a runaway system. That's why SSB recommends setting it between 28°F and 32°F.

Unfortunately there is no easy solution. The surface of the coil is quite small combined with rather poor insulation this means you won't be able to go lower than that. The issue is worse the smaller the fermenter is and the 7 gal is the smallest of the line so it's hit the hardest.

The only practical workaround would be to greatly improve the insulation by placing the whole fermenter in an insulated box but that kind of voids the advantage of using a glycol chiller.

 

[CodeSection]

I always went with another member's observation that you can easily lower the glycol setting and avoid pop cycles forming around the coils when you use the formula of roughly .8 times the ABV percentage which will give a number to subtract from 32F.

https://www.homebrewtalk.com/forum/threads/freeze-point-calculation.601284/

As an example, a brew with an estimated ABV 5%, .8 x ABV 5 = 4F; 32F-4F=28F. So, SBB lower range is based upon ABV 5%. I typically brew 7-9% brews, so my glycol setting is lower.

https://www.homebrewtalk.com/forum/...s-penguin-vs-any-others-not-diy.668671/page-2

The above seems conservative based upon a quick google search....but I will stick using the .8 formula.

https://www.quora.com/How-can-you-calculate-a-beers-freezing-point

https://shotgundentist.com/blog/usefull-tools/alcohol-percentage-to-freezing-point-calculator/

 

[OnTheFlyBrewing]

Well...that's not the kind of reply I was hoping for.

I bought the chiller direct from SsB. This is all very disappointing. My science/physics understanding is reasonably good for the average person, but I am having trouble wrapping my brain around this. The fact that I can chill the glycol to below freezing, then circulate it through the unitank chiller coil almost continuously, and it will not drop the temp below 38ºF is perplexing. Add to this that the glycol chiller maintains the glycol temp very close to whatever I set. It does not seem like there is a problem with the output of the chiller. What does make sense to me is the idea that there is insufficient insulation to reduce the heat exchange with the ambient air.

SsB has a knowledge base addressing the formation of ice on the coil inside the fermenter, and they recommend stepping down the temp slowly with periods in between the chilling to allow the ice to melt.

This is very frustrating.

 

[OnTheFlyBrewing]

I always went with another member's observation that you can easily lower the glycol setting and avoid pop cycles forming around the coils when you use the formula of roughly .8 times the ABV percentage which will give a number to subtract from 32F. As an example, a brew with an estimated ABV 5%, .8 x ABV 5 = 4F; 32F-4F=28F. So, SBB lower range is based upon ABV 4%. I typically brew 7-9% brews, so my glycol setting is lower.

This is what I've used also. With a 4% ABV, I should be able to circulate glycol that is as low as 28.8ºF without freezing the water in the beer. I've tried setting it at 29.5ºF just to be sure, but still cannot lower the temp.

Befuddled.
Greg

 

[OnTheFlyBrewing]

I asked SsB support, and they replied with...

Hey Greg,

Thanks for reaching out. Generally, ambient temperatures can really affect cooling capabilities. The general rule is if the chiller is reading 28F you would expect a delta of 6-10F on average. Basically the difference of a 6F ~10 F inside the vessel from what the glycol is reading. This delta range can be helped with lower ambient temperatures outside of course. Other factors such a glycol to water ratio, line length, line insulation, temperature calibration on both the FTSs and the glycol unit, and again ambient temps. For the glycol, we recommend a temperature of 28-30F with a 35% Glycol to 65% water @ 24.75 brix, this is really the real sweet spot to achieve the best thermal energy exchange. If you are encountering a freezing coil inside of the tank it may be best to step the temperature down 1*F at a time to prevent ice from insulating the chiller coil.

Even if you added additional insulation and doubled your chillers BTU/hour, you would likely not get a significant change in your temperature floor. Considering serving temperature is usually 38F, getting down to 37F is plenty cold!

Cheers!

 

[Jtvann]

Another thing to look into is your batch size. To reach the coldest temps possible, you need as much of the chiller coil in contact with liquid as possible.

I was able to get my DIY chiller and 14g unitank down to 35 degrees without continuous recirculation. This will be my first day using my 1/5 HP Ssb glycol chiller. I'll let you know if I have any better luck in about 2 weeks.

Previously i kept my reservoir set at 28 degrees.

 

[CodeSection]

As @Jtvann asked....https://www.homebrewtalk.com/forum/threads/ss-1-5-chiller.675367/

 

[Jtvann]

I'll add to that, you notice that the controller was not running when the picture was taken. I don't know how cold the chiller can cool the unitank, but it hit 35 for me easily.

Big key that helps, keep the unitank full. I put at least 12 gallons in. I minimize trub dumping.

 

[OnTheFlyBrewing]

Ran the chiller on my second batch, an Irish Red Ale. Crash cooled it right to 33ºF without a problem. I feel that this is largely due to the alcohol content of this second beer. First one where I had trouble was only around 4%, but this Irish Red Ale is about 6%.