Thinking about water bath fermentation

[sdufford]

For my second brew, I'm thinking about doing some sort of water bath fermentation. I would guess my first ale fermented around 72-75 degrees, which from what I gathered is a little on the high side. I was think of shooting for something around 65-68 degrees. How does this sound?

My other question is, will the the gradual yet consistent temp fluctuations from my crude water bathing be bad for the brew? I think I could keep it in the 65-68 range, yet I imagine it will be a constant 65 to 68 back to 65 cycle as I'm in and out my apt quite a bit.

Is this still gonna be better than a constant 74 degrees?

 

[iron_city_ap]

I've read that as long as you try to keep the yeast in the 70 degree range and keep the temperature from shifting more than 10 degrees/day you should be okay. Alot of it depends on the yeast you are using. There are some that are more temperature sensitive than others, but for the most part the 70/10 thing should keep you good for 99% of what you will be dealing with.

 

[doctorRobert]

There are some that will disagree with that and say 70 is way too high, even for hefeweizens. Also, are you talkin about ambient temps or wort temps? Wort can be 10 degrees higher than ambient temperature, in which I also think 70 ambient temp is too high.

 

[SenorD]

How are you planning on chilling the water? I've got a batch right now living in a half-filled bathtub with a fan blowing over it (ghetto, I know- temporary measure until I finish building my fermentation chiller), and it's maintaining at around 68 (8 degrees below ambient) just by evaporative cooling. If you're generous and consistent with ice usage, I'd imagine you could get it quite a bit lower.

That said, I don't think a 3-degree temperature swing will hurt your yeast. Bear in mind though that in an active fermentation, the wort can heat up by an impressive amount without being actively cooled.

 

[sdufford]

Well, a cup of water in my second bathroom where I fermented was holding around 72 degrees, I was thinking the wort/beer would only be a few above that. Didn't know it could be up to 10 degrees higher, that's quite a difference.

So all the more reason I should think about getting a water bath goin. So holding a water bath around 65 degrees would still place my actual wort temp in the lower to mid 70 range.

 

[joelmole]

If you want you can follow my first batch thread as I went with a water bath, which so far has been surprisingly successful. When it comes to fluctuations, I can say mine fluctuates between 63 to 65 degrees, usually doesn't hit 65 though, typically 64 and change when I change out the ice pack, which drops it back down to around 63, or maybe a bit lower. I have an analog thermometer clipped to the side of the cooler, but when I check on it every 6 hours or so I use a digital thermometer with .1 degree accuracy.

I didn't try the Rubbermaid tub route, so I don't have a basis for comparison, but anecdotally I think using a cooler really helps, should dampen ambient temperature fluctuations better, and will help maintain lower temps for a longer time. I cover the cooler with towels with only the carboy neck poking out, to help insulate the cooler better since I can't lower the lid. This also keeps the carboy in the dark, so I don't have to keep this in a closet to eliminate light spoilage.

Link to thread

 

[sprocketmaker]

Wow, is that wort being 10 degrees hotter true? As my garage is holdng petty close to 70-72 right now, which I felt was pretty good fermenting temps for my stout and hefe weisen... Should I be concerned with off flavor and other issues fermenting at these temps?

 

[Teromous]

So long as the yeast is in optimal temperature range it should work just fine. Many people use the towel + fan method...another thing you can do if you have any empty plastic bottles is to fill them with water and freeze them. Just replace them whenever you get home or notice they're melting. Make sure it doesn't get too low though

 

[944play]

Wow, is that wort being 10 degrees hotter true?

Absolutely. In a closed system with a normal-gravity beer it's more like 25ºF.
https://www.homebrewtalk.com/f14/in...rmenting-primary-produces-101334/#post1108396

So take 10L (2.6 gal) of a 13ºP (1.053) wort, ferment it to a 3ºP (1.012) beer, you have 140 kcal heat produced. In a closed system, that would heat the beer by 14ºC (25ºF) by my cocktail napkin.

 

[Yooper]

Wow, is that wort being 10 degrees hotter true? As my garage is holdng petty close to 70-72 right now, which I felt was pretty good fermenting temps for my stout and hefe weisen... Should I be concerned with off flavor and other issues fermenting at these temps?

Yes. Unfortunately, if your garage is 72ish, your fermenting beer could be anywhere from 75-82 degrees. Way too high for good flavor in most ales.

It seems like the hotter the fermentation starts, the hotter it gets. For example, if you pitch the yeast into 62 degree wort into a 62 degree room, it may never get much above 65 degrees. But yeast love warmer temperatures, and start fermenting faster. That creates even more heat, which makes them go even crazier, and pretty soon you have a "hot" fermentation going, sometimes even explosive.

A water bath helps a lot- even if it's not much cooler, in my experience. Here's why- it takes LONG time for 5 gallons of wort and 4 gallons (more or less, depends on your water bath) to change temperature. So, even if the room gets warmer while you're off at work, it doesn't seem to affect the temperature of that much liquid that quickly.

I like to toss a frozen water bottle or two into my water bath, too, which really helps. I keep a floating thermometer in my water bath, so I can get a quick idea of fermentation temperature.

 

[sprocketmaker]

My beers are in secondary... Phase, and gave been fir almost 3 weeks... Primary ferm was over a month ago, in the house at a more manageable temp (mid 60's) for their first weekish. We did experience an early heat wave, where indoor temps got into the mid 70's, that is why I moved everything, two fermenting beers and 50 conditioning bottles into the garage, where temps were holding 5-10 degrees cooler. The IPA in the bottles, was tasted this last weekend, with a satisfactory result. Hopefully the other two beers will fair as well.