repercussions for temperature fluctuation during fermentation.

Going on 10 days in primary. We are storing our beer in a Treehouse outside because that's where we brew, bottle, etc. Past couple nights it has dipped down to the 30s. What are the ramifications if your fermenting temp goes high or low? I know optimum temperature is room; around 60-70 degrees. Any input would be appreciated.

If you are hitting ambients of 60-70 as your highs then your yeast will take a long, long time to properly ferment. Each time the brew gets cold enough they go to sleep, then as it warms back up, they wake back up and have to start at work again. You would have lag times and breaks in fermentation. Your attenuation probably won't be great, from what I understand, but you would need to ferment a while longer to compensate.

Why can't you move it right inside? Stability would really help.

What type of beer and yeast are we talking about? You really need to bring that beer into the house. Severe temperature fluctuation will stress the yeast and cause them to throw off flavors, or not finish fermentation. Most ale yeast stop working and go to sleep once the temp starts heading much below the low 60's. Above the low 70's they can throw phenols and create harsher higher alcohols during fermentation. Temperature control during fermentation is one of the single most important things you can do to ensure your beer turns out it's best.

You're going to have all kinds of off flavors going on. You need to have either a steady fermentation temperature or a slowly rising one. Off-flavors like acetaldehyde (apple cider) and diacetyl (butterscotch) form during fermentation that get reabsorbed during vigorous stages that you are introducing to your beer. Not to mention you're going to have poor attenuation. Like it was mentioned earlier, when you let the beer cool down like that, the yeast are just going to want to drop out and go into survival mode.

Even lager yeast pretty much stop fermentation below 40F

Brewing in a treehouse? Are you 12?

Buy your beer a snuggie. Cold nights will make your beer sick.

dlaramie08 said:

Brewing in a treehouse? Are you 12?

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treehouses are awesome!

I doubt the op's treehouse looks like the one at DFH

Thanks for the help guys. Trust me we have discussed in length to keep carboy inside. I'm really not sure what made us keep it outside in the treehouse. Our mess up. Brewing an IPA btw.

atom said:

treehouses are awesome!

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