Cool Brewing Fermentation Cooler, dialing it in

[Mothman]

I'm waiting on delivery of a Cool Brewing Fermentation Cooler to finish my collection of brewing gear.

When I do my first brew, I'll be using a fermentation bucket in the cooler, and plan to monitor the temperature either through a stick-on thermometer, or by taping the probe of a digital cooking thermometer to the bucket.

I anticipate that the temperature will fluctuate some as I'm working out how many ice packs to use, or if I'll even need ice packs (depending on what room I end up using, our laundry room tends to be quite cool).

My question is, how much am I going to stress the early fermentation if it takes me a day or so if fiddling with the ice packs, trying to dial in the appropriate temperature?

The hope is that even with fluctuations, I'd stay within a recommended range of whatever yeast I use, but I might have it stray outside of that range temporarily if I'm not totally on the ball.

Going in blind, I have no idea whether to start with a couple liters of ice, a couple gallons, or something in between.

 

[cubalz]

You said "finish my collection of brewing gear". I have never heard of such a thing, there is always something else... If anything I would err on the side of over cooling it which really has the only effect of slowing the yeast fermentation. Once you get it right they will kick back in. The first 3 days of fermentation are the most critical as that is when it is the most active and therefore causes the heat to rise within the carboy.

 

[Mothman]

Hahaha, I should have said, "got enough stuff to start actually brewing, so I can temporarily halt going to Canadian Tire to get new oven mits, and returning with $75 worth of odds and ends that seem suited for use in brewing".

Thanks for the over-cooling advice... I didn't connect the dots to understand that I wouldn't hurt anything by overshooting the on the cold end.

 

[BeerAddikt]

I use frozen 2 liter bottles in my bags. Each bottle drops the temp approx 5 degrees from ambient level and will melt completely at around 24 hours and need to be swapped (I tend to cycle them every 12 hours just to minimize fluctuation.)

At the moment ambient temps in my house are around 68 so I only add a single bottle at about the 24 hour mark when the fermentation really kicks into gear and raises the wort temp up to around 70. After about 48 hours (24 hours with frozen bottle in bag) I usually remove the bottle as things start to wind down. Temps fluctuate between 65-68 based on my current usage pattern.

In the summer I usually have to keep 1-2 bottles in the bag at all times to hold temps between 64-68 degrees (ambient temp is between 70-75 in the summer). It won't take you long to dial it in. Just watch out for the active fermentation period when the wort temp naturally rises and more bottles may be needed.

 

[Mothman]

Hey BeerAddikt, thanks for the first hand info.

Couple follow-up questions for you...

1 - you mention you usually remove the ice entirely at this time of year, once things settle. At that point, is there any benefit to keeping the wort inside the cooler? Do you think keeping it in the cooler, with no ice, helps 'cushion' it against minor ambient temp. fluctuations through the day?

2 - what do you use to monitor your temp's?

 

[tgolanos]

Hey BeerAddikt, thanks for the first hand info.

Couple follow-up questions for you...

1 - you mention you usually remove the ice entirely at this time of year, once things settle. At that point, is there any benefit to keeping the wort inside the cooler? Do you think keeping it in the cooler, with no ice, helps 'cushion' it against minor ambient temp. fluctuations through the day?

2 - what do you use to monitor your temp's?

From my own experiences:
1- There's some cushioning, but not much. The temps in my cool bag can easily reach ambient if I don't swap the ice out every 24 hours. In summer in Sydney, that can easily mean 26°C-30°C in the coolest room of house. This is OK (IMO) for storage post-fermentation, but not during active. In winter, I use less ice but enough to maintain a temp of about 10°C inside the bag.

2- I just use my stick-on thermometers. I know they're not 100% accurate but I can make some logical assumptions as to current and fermentation temperatures. I know with 5 2L ice bottles, the strip reads 10°C in summer, meaning my active fermentation temp is around 12-15°C. I add more ice as needed to keep my beer within yeast range.

This being said, don't be afraid to play with your ice amounts and adjust as necessary. Just make sure you have enough room in your freezer for the correct amount of bottles.

 

[Mothman]

Great info, thanks.

How long should a person wait for the temperature to stabilize after changing the amount of ice, before checking what the new temp. is?

I'm very excited that this bag works well for you even in your summers. Here in the Okanagan Valley in BC, Canada, we get hot summers as well, and a mid-20C daytime indoor temperature isn't uncommon for us.

 

[ncbrewer]

I've had fermometers quit working when I cooled to 58F and got condensation on them (water resistant, but not water proof). I'm wondering if keeping the fermenter in the cool brewing bag with bottles of ice would create condensation (with normal ale temps of mid to upper 60's). Anybody have experience with this?

 

[tgolanos]

I've had fermometers quit working when I cooled to 58F and got condensation on them (water resistant, but not water proof). I'm wondering if keeping the fermenter in the cool brewing bag with bottles of ice would create condensation (with normal ale temps of mid to upper 60's). Anybody have experience with this?

I get plenty of condensation on the outside of my fermenters. I haven't noticed any negative effect on my beers (lager or ale) as a result. That being said, I regularly check my seals and bungs for signs of mold and rot. If your seals go, then there's risk from the condensation spreading bugs, I guess.

I wouldn't think condensation would cause your yeast to go dormant, anyway. Your issue there is too low temperature for your yeast.

How long should a person wait for the temperature to stabilize after changing the amount of ice, before checking what the new temp. is?

Hard to say. I'd guess no less than 12 hours and see how far your temperature dropped. Then check it again when you swap the ice out. Like anything in brewing, just keep good records and adjust as necessary. If it helps, I know from being impatient and checking more frequently than I should I can drop my temps 5°C in about 10 hours with 5 frozen 2Ls.

 

[Mothman]

I wouldn't think condensation would cause your yeast to go dormant, anyway. Your issue there is too low temperature for your yeast.

Just a note, ncbrewer was saying that his fermometer has stopped working (due to condensation?), not that his fermentation, or beer, was impacted.

If it helps, I know from being impatient and checking more frequently than I should I can drop my temps 5°C in about 10 hours with 5 frozen 2Ls.

I'm surprised by those numbers. Cool Brewing, in their FAQ (and I think also in discussion threads here at HBT), talk about a single 2L of ice providing around a 5*F drop below ambient.

You're only getting 1*C per 2L (1.8*F)?

 

[popsicleian]

After a lot of playing around, I have found that I get the best results by overcooling, then using a cheap fermwrap and temp controller to heat to my desired temperature. Much more accurate than trying to figure out the best combination of water bottles and freezer packs, with the added benefit that you're less likely to stall out the yeast when the temperature starts naturally dropping near the end of fermentation.

 

[tgolanos]

Just a note, ncbrewer was saying that his fermometer has stopped working (due to condensation?), not that his fermentation, or beer, was impacted.

Ah, that makes much more sense now. "Fermometer", not "fermenter" as I originally read. Not to self, don't answer forums until I've had a cup of coffee in the morning!

I'm surprised by those numbers. Cool Brewing, in their FAQ (and I think also in discussion threads here at HBT), talk about a single 2L of ice providing around a 5*F drop below ambient.

You're only getting 1*C per 2L (1.8*F)?

Could have to do with the summer weather? We've had a brutal one, so I wouldn't be surprised if the ice is melting too fast. I'll have to take a closer look come winter and see if the temps drop faster or more drastically. You've got me curious now.

Also, that's only after about 10 hours, so it's probably still dropping. I can easily maintain a temp of 10°C with the same amount of ice bottles.

 

[Mothman]

Also, that's only after about 10 hours, so it's probably still dropping. I can easily maintain a temp of 10°C with the same amount of ice bottles.

That's awesome.

 

[BeerAddikt]

Great info, thanks.

How long should a person wait for the temperature to stabilize after changing the amount of ice, before checking what the new temp. is?

I'm very excited that this bag works well for you even in your summers. Here in the Okanagan Valley in BC, Canada, we get hot summers as well, and a mid-20C daytime indoor temperature isn't uncommon for us.

I also use the stick on fermometers for temp measurements...accurate enough for me. I try not to over cool because I've had fermentation lag on me before due to temps getting near 60F. The main thing that I focus on is keeping the fermenter below 70F. At the moment I have a batch that's at 24 hours with a single bottle and it's at 64F.

My temps usually stabilize at around 4-6 hours. Depends on how much I'm trying to cool it down.

The only condensation that I get is from the melting 2 liter bottles but I make it a point to wipe up the condensation when I swap out bottles.