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Oatmeal Stout won't stop fermenting

I brewed a NB Partial Mash Oatmeal Stout 5 weeks ago. It has had slow but steady fermentation since the beginning. After about 2.5 weeks at low to mid 60’s, I moved it to room temps to finish up. It never really did. Still lots of foam on the top and fairly slow airlock activity. Along with two other brews, I transferred to secondary on Friday night while brewing other batches. Yesterday, the other two were as I usually see them, no activty, just clearing.

But the Stout had a pretty nice layer of foam and somewhat steady airlock activity.

OC was about 1.051 and when I transferred to secondary it was 1.010. Should I let it keep going? Sample I tried was excellent and was the first time I think I fully understood “mouth feel” Really smooth.

How low should I let this go?

at one ten its probably done, have you checked it for more than two days in a row? if its the same then you’re done.


What is the downside to letting it go another week? If “done” means are fermentables are consumed, what is happening now?

At those temps you probably just had a really slow fermentation. Bringing it up to warmer temps likely kicked the yeast into high gear. I agree that at 1.010 you are likely reaching terminal gravity. You should leave the beer alone until the (obvious) activity ends. At that point you might want to help clear the beer by moving it into a secondary vessel. But that isn’t necessary.

The yeast will continue to clean up the beer a bit beyond the time you reach terminal gravity–consuming things like esters or fusel alcohols. You can safely leave the beer in primary for 4 weeks or so, if you like.

What is the normal terminal gravity for this type of stout? I am sort of new to stouts. Is it possible to make them too dry? Is it normal for them to go this low?

Dry stouts have low finishing gravities. Like 1.010, or perhaps a bit lower. If you hit 1.010 I’m sure it will be great. Of course, oatmeal stouts, from my experience, have bit more sweetness. But I’m sure you made a tasty brew.

It was really tasty when I transferred. It seems to be slowing back down now and cleaning up a bit. I just was not sure if there was a point where something like a stout can go too low and you want to stop the fermentation to keep it from getting too dry.

Thanks for the tips

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