[100% Brett] Active fermentation but little reduction in gravity

[Microphobik]

Hi all,

I am fermenting my first 100% brett beer. It's a pretty typical American Pale Ale (OG 1.052) that I split into two 5 Liter carboys (4 Liters of wort) and pitched a vial of WLP645 into one, and WLP648 into the other. No starter but my hope was that it would be ok for just 4 liters.

It took about 48 hours to see any signs of fermentation, but once they took off they were both very vigorous with the Krausen blowing through the airlock on the WLP648. While still quite active, I noticed activity starting to slow down after about two days of vigorous fermentation. In my Sach beers this usually means things are a day or two away from terminal gravity, but this surprised me with Brett. So I took a refractometer reading (adjusting for fermenting wort in beersmith) and the calculator is telling me I'm only down to 1.045. That's a lot of sugar left for a fermentation that seems to be slowing down. Is this normal? Does Brett ferment vigorously through the growth phase but chew through the sugars slowly, or is something potentially wrong? I started at 70 degrees and have been nudging it a degree a day since seeing signs of fermentation. Just wondering what is normal.

Thanks for any advice.

 

[m00ps]

brett has different growth phases than sacch. I notice this whenever I do brett starters. They take much longer to go through the sugars

The 48hr lag time also probably is an indication you stressed the yeast. Just be patient and let it finish

 

[Microphobik]

Thanks. I didn't realize it at the time, but after reading up on it, it seems clear I under pitched by quite a lot. One of the beers (The Vrai) has chewed through most of the sugars by now and is around 1.011 and the yeast cake has compacted like a normal fermentation. However the Clausenii is behaving strangely and seems to have stalled out around 1.035. It is starting to clear and fermentation seems completely done, and yet the yeast cake has not compacted and there are plenty of sugars left. It also smells and tastes quite bad, like rotten pineapples. The Vrai also has a rotten pineapple taste but in a much more pleasant way, if that makes any sense.

I have had a number of commercial 100% Brett beers and they were all very clean, with just a trace of Brett character (which I realize is normal). But even the better of the two beers seems a long way from clean. Does it take a long time for the flavor to mellow, or does this indicate that these batches are possibly ruined because of the under pitching? I'm having a hard time visualizing something that tastes like rotten pineapple juice transforming into a relatively clean beer. But I don't know what's normal here.

 

[m00ps]

The flavors will definitely change. Hopefully they will get more clean. Brett seems to be really funky while it is fermenting, at least in the smell. Ive found with my brett beers, the more strains you have, the better.

I might try getting some 100% brett commercial beers and either making a starter from their dregs or adding them right into the fermentor

 

[Microphobik]

Thanks. I had it in my head that it would be fun to keep a bunch of isolated Brett strains, but I think mixing them is going to be the way to go, as you suggested. I may just pull off the dregs from my vrai beer and add them to the Clausennii beer and see if that doesn't help it along. Thanks for the perspective.