Fermentation Temperature Question

[houstonbg]

I'm currently brewing Mr. Beer's "Classic American Light" recipe and am a little worried about the fermentation temperature. The instructions say to keep it at 65 - 75°F, and 75°F is what I keep my apartment set at.

However, that's at the top-end of the range and I know heat is thrown off during fermentation.

I have a number of questions, but mainly I'm curious to know whether or not my worry is warranted, how much heat is given off during fermentation, and the easiest way to cool the beer down to temperatures at the lower-end of the range without access to a temp controlled fridge.

The batch is roughly 12 hours old, by the way. I don't know if that's pertinent information, but I figured I'd let you know.

Any and all help is greatly appreciated!

 

[jekeane]

Fermentation temps are likely the number one difference between a good beer and bad beer, when everything else is equal. In general you want to keep a yeast in the lower third of its temp range. If ambient temp is 75 you can bet you beer will be closer to 80 during peak fermentation. You have a good chance of making rocket fuel or some other yuck at that high a temp.

Getting a Rubbermaid tub and make an ice bath of some sort would help your beer a lot. google mr beer swamp cooler for ideas.

 

[houstonbg]

Fermentation temps are likely the number one difference between a good beer and bad beer, when everything else is equal. In general you want to keep a yeast in the lower third of its temp range. If ambient temp is 75 you can bet you beer will be closer to 80 during peak fermentation. You have a good chance of making rocket fuel or some other yuck at that high a temp.

Getting a Rubbermaid tub and make an ice bath of some sort would help your beer a lot. google mr beer swamp cooler for ideas.

Thanks for the info, jekean! Quick question: Is 5 degrees a fair addition to ambient temp to gauge temp during peak fermentation? I imagine it varies, but does the 5 degrees generally hold true anywhere in that range, i.e. at 65 degrees ambient, it's likely 70 at peak fermentation?

 

[number40fan]

Yes, 5° is a good gauge to use.

 

[jekeane]

I believe 3-5° is the general estimate throughout fermentation. There will even be a gradient on from the center of the beer to the outside of the fermenter. That gradient is likely small with MR beer but with a 5 Gallon batch i can be 1-2° between center and the fermometer. I imagine when you get into 10-20g batches that temp difference could be quite significant. That's why interior thermometers are the bees knees.

 

[Calder]

I believe 3-5° is the general estimate throughout fermentation. There will even be a gradient on from the center of the beer to the outside of the fermenter. That gradient is likely small with MR beer but with a 5 Gallon batch i can be 1-2° between center and the fermometer. I imagine when you get into 10-20g batches that temp difference could be quite significant. That's why interior thermometers are the bees knees.

With all the churning going on at the height of fermentation, it will all be at the same temp; no temperature gradient.

 

[MindenMan]

As far as I can figure, any attempt at controlling fermentation temperature is a bonus. Granted, yeasts have their own optimal temperature ranges to produce the best results. A bath tub with water, a bath tub with water and a tee shirt, wet tee shirt and a fan, all are of some help. The results might not be the best possible, but they won't be the worst possible eithier.

 

[stevehardt]

Back in my Mr. Beer days (I loved that LBK), I just kept a towel over the LBK (helped keep the light off it) and kept a few cooler packs leaned up against the LBK. Kept my temps down nicely. Mr. Beer also sells some stick on thermometers. No exactly pin point accurate, but always seemed to help me keep my temps reasonable. Worked well and was a lot easier than a swamp cooler, etc.

Hey, congrats on your first batch. Welcome to the hobby. And you can make some damn good beer with Mr. Beer!