Pitching on a very old mixed cake

[jordanfrenzy]

Hi All,

I decided I wanted to re-use an old yeast cake from a sour to ferment 3 "side gallons" from an 8 gal batch. I figured it would be a mix of the dregs (Brett B) and the original saison yeast I first fermented with.


I, very stupidly, did not think about the fact that this cake is nearly 10 months old.

Brew date was 12/14 and today on 12/18 I pulled a sample. There was already a pellicle forming, but the beer was very sweet still. (OG was around 1.042) I pulled some Belgian yeast I had on hand and added it to the fermenter.

My question is what are the risks here for a beer that sat 4 days with minimal fermentation? Botulism? How would I identify that?

 

[Hopper5000]

If there was a pellicle forming then that means the bugs were working. I wouldn't worry too much about anything negative like botulism in there. It's good you pitched some more yeast in there as the old cake probably had minimal viability at that point. However, some of the "bugs" have a very long shelf life.