Washed yeast storage and botulism

[albannach]

I searched and surprisingly couldn't find anything on this topic.

With washed yeast (washed using boiled and unaerated water and stored in canning jars in the fridge) do you have to worry about botulism growing in there? I just freaked out today and realized that it's an anaerobic environment and has a neutral pH. Thoughts?

 

[Yooper]

I searched and surprisingly couldn't find anything on this topic.

With washed yeast (washed using boiled and unaerated water and stored in canning jars in the fridge) do you have to worry about botulism growing in there? I just freaked out today and realized that it's an anaerobic environment and has a neutral pH. Thoughts?

No. You store the washed yeast in the fridge.

 

[conpewter]

No. You store the washed yeast in the fridge.

Exactly, botulism won't grow/produce toxin at lower temps. This topic comes up a lot when people talk about canning wort, and the no-chill method for wort cooling. Both of which are safe as long as they are done correctly.

 

[Schlenkerla]

I have a jar of yeast from a washing that has floating mold nodules on it right now. I was pissed to see this. It was my special homegrown strain.

I have done this 6-8 times without trouble.

I boiled the lid, jars, water and I still have something that infected the SOB. It was in the fridge from day one too.

You can buy this from NB. I will soon. (See yeast nutrients) NORTHERN BREWER: Yeast Handling Supplies

Chlorine Dioxide Tablets. Chlorine dioxide tablets can be used to kill bacteria in the slurry when harvesting yeast for reuse, without the negative impact of an acid wash on cell health. Chlorine dioxide isn't a substitute for good sanitizing, so keep all yeast handling equipment clean!
To use, collect slurry from the fermenter, add cool sterilized water to approximately double the volume, swirl vigorously, and then allow trub to separate. Decant the top (yeast) layer into a sanitized flask, add one crushed chlorine dioxide tablet to the yeast layer, and top up with more cool sterile water to bring the volume to 1 liter. Allow to rest for several hours, then decant the clear top layer — the yeast can then be directly pitched into a new batch. Includes 20 tablets.

 

[albannach]

If I kept washed yeast for many generations, chlorine dioxide would be the way to go. For now I just extend to use of a strain to 2-3 batches before buying a new smack pack or vial.

Good to know that botulism won't grow in the fridge.