Fermentation sliding scale

[LoudounBrew]

Alright. I checked a couple of threads on this, but I haven't quite seen a direct answer to my question. My basement is a constant 68 degrees - even in summer, so I have a warm cave of sorts.

So let's say that the best fermentation temp for a yeast is 66-70 degrees. From an ambient temp standpoint, I'm fine. But once the yeast gets rocking, temp inside the carboy is going to increase 4-10 degrees. If the room is 68, we're talking about a beer temp of 72-78 and that could be a problem.

On the batches that I've done, the thermometer on the side of the carboy goes from 68 to ~71-72 when fermentation is at its peak.

So couple of questions:

1. Does the thermometer of the side of the carboy tell me much or does it more or less give me the ambient temp?

2. If the beer really is going over 70 degrees for a couple of days, is that a concern or do we not need to worry about the production of off flavors during that early stage?

3. If that is an issue, should I do a swamp cooler for the first couple of days (I'd wait until the fermentation really got started) to bring the temp down five degrees or so below the ambient temp of 68 (i.e. 63 degrees combined with say 5 degrees from fermentation equals a perfect 68 degrees) and then take it out and just let the carboy sit in the 68 degree ambient after that, since there wouldn't be much heat being generated from the fermentation after three or four days?

The more I read the more I see about controlling the fermentation temp, so I'm getting concerned that the 68 degrees in my basement - which I thought was great for ales - isn't really 68 degrees, at least not inside the carboy.

Thanks for any help.

Brew well, brew often,
LoudounBrew

 

[iron_city_ap]

I always use a swamp cooler. In fact, I rarely drain them. I put in sanitizing tablets to keep the water from getting skunky. The water keeps the beer cool during fermentation, but it also insulates the beer against temperature fluctuations (power/heat/ac failure, swmbo gets cold and cranks the heat......) after fermentation is complete.

 

[Ryush806]

I would definitely use the swamp cooler. I was skeptical of how well they would work especially with the humidity where I live. It was very nice to see that I could drop the temp to 65 in the water sump while keeping the A/C set at 73. They are definitely the best way to go if you don't have the money or space for a spare fridge. You can even make one out of a $15 aquarium pump, aquarium tubing, and a 4 way aquarium splitter valve available at Wal*Mart.

 

[LoudounBrew]

Thanks for the help.

So let me get this straight, just to be sure. A room at 68 degrees for a yeast that asks for a temp of 68 isn't correct when the fermentation is going full steam. I need to bring that temp down - at least for the first couple of days - to counteract the heat generated by the fermentation.

Well, then, what's the fricking point of the thermometer stuck to the side of my carboy. I mean, I guess that it's useful after that first burst of fermentation is done (4-7 days), but it's not telling me much during those first few days. Is that correct?

Again, thanks for the help. I'm just trying to move to the next level.

 

[Ryush806]

That thermometer on the side is going to be a better indicator of the actual beer temperature than your thermostat, but the fact that it's on the outside of the fermentor means it's influenced by the colder room. My father and I actually use a controller with the temperature probe inside a thermowell inside the carboy. It usually reads about 3 degrees higher than the stick on thermometer during peak fermentation.

 

[LoudounBrew]

Thanks. That's about what I thought. So it looks my perfect 68 degree basement isn't perfect after all. I'll need to get the air temp around the carboy down ~4-6 degrees during the first three, four or five days to counteract the heat generated by the fermentation. A swamp cooler should do the trick. I already have a tub and a fan, so no big deal.

Man, I thought that I had it easy with the basement temp being 68 degrees. Live and learn, I guess.