Rescue Yeast?

[Brew-Jay]

I've got a Belgian Saison (WLP568) fermenting in the garage. It's been there for about two weeks. The problem is that it has been very hot in So. Cal lately and the fermentation has undergone some bad temperature swings. I know 568 does ok with higher temps but I'm worried that the variation might cause some off favors. I have an extra vial of 568 in the fridge that I might not otherwise get a chance to use. Should I pitch it and let the little guys clean up after their brothers?

 

[iambeer]

I don't think so, but you can start planning on how to control the temperature for the next batch. It's really worth it--or I mean, it's necessary.

 

[Calder]

It would be a waste of yeast. With the alcohol and lack of O2 (and no you don't want to aerate now), a lot of the yeast will die from the shock, and the rest will not reproduce. You have billions more viable cells in the beer already than you would get from pitching a new vial.

Keep it in the fridge. In a year when you want to use it again, you can make a starter and it will wake up. You will need to use a starter, as you will lose a lot of the cells over a year of storage and straight pitching an old vial is seriously under-pitching and will have problems.

A simple method to control temperature swings is to get a really big plastic bucket (think cheap from Walmart), place the fermenter in the bucket and then fill the bucket with 10 to 15 gallons of water. The larger the liquid volume the slower the temperature change. It will also act as a heat sink and limit the temperature rise of the wort due to fermentation generated heat.