WLP568 double ferment???

[millsbrew]

I had this yeast on hand for 3-4 months. I have built up a starter 2 times for 3 batches (basic saison, braggot, and a this batch was a Belgian single). The Belgian single had 22IBU (the highest of the 3 batches) and an OG of 1.050 (the lowest of the 3) which included 0.33# of sugar. The saison (OG 1.061) was fermented at 76dF, the braggot (OG 1.075) started at 69dF then raised to 74dF over a few days. Both of those finished fermentation in 9 and 10 days respectively. I pitched the single at 68dF, on day 4 I started raising it 1dF every 12 hours. I hit 73dF the evening of day 6.

After 8 days, I took my conical out of the ferm chamber to keg the single. The airlock had not been bubbling on days 7 and 8. I opened the lid and there was still a slight krausen. So I figured I would come back in a couple hours to finish kegging. My basement is 68dF. Well I got sidetracked and went back day 9. The krausen was bigger. Still going on day 10.

Is it possible for my beer to start a second fermentation? I have sours around in glass but this is in my SS conical and Brett wouldn’t show a krausen on day 7.

TL;DR - How on earth is a 1.050 still fermenting on day 10???

 

[Vale71]

This is a known diastaticus strain. Search for diastaticus in the forum and you'll find tons of useful information about it.

 

[millsbrew]

Thanks. I knew it was STA1. Didn’t know about the diastaticus. Sucks cuz I was going to do a split batch with Brett C.

 

[isomerization]

Thanks. I knew it was STA1. Didn’t know about the diastaticus. Sucks cuz I was going to do a split batch with Brett C.

STA1 is the gene that encodes glucoamylase. The presence of this gene leads to classifying yeast as diastaticus. They are one in the same. Caveat, sometimes the gene is not actually expressed, leading to false positives. I’d guess your strain is a true positive

See this for more info:
http://beer.suregork.com/?p=4068

 

[brownni5]

Thanks. I knew it was STA1. Didn’t know about the diastaticus. Sucks cuz I was going to do a split batch with Brett C.

Why can't you? I've added Brett to some pretty dry stuff and have gotten good results.

Not saying I understand the phenomenon you saw. That in itself isn't explained as just being a diastaticus strain. At least in my experience that's not how they work.

 

[Vale71]

Thanks. I knew it was STA1. Didn’t know about the diastaticus. Sucks cuz I was going to do a split batch with Brett C.

Pending further genetic research it's safest to assume that all STA1 strains will overattenuate to some degree or other. If one is not OK with that one should pick a different strain to avoid surprises.

 

[brownni5]

Pending further genetic research it's safest to assume that all STA1 strains will overattenuate to some degree or other.

I would say that they attenuate exactly as much as they intend to. Overattenuation is in the eye of the beholder.

What gets me is when a yeast lab lists it as diastaticus or STA1 positive, and then lists expected attenuation at 75%, that's where people get in trouble.