Fermentation Performance of Refrigerated Yeast Slurry

[Tinpanharry]

Woodlandbrew Thank You! I am buying your book tonight to support everything you do and all of the time you put in to help us improve our homebrew.

Cheers to you

TPH

 

[WoodlandBrew]

Thanks! I appreciate it!

 

[Tinpanharry]

Awesome work Woodlandbrew! Legend-(wait for it....) - Dary!

 

[fakeuser]

This thread might be relevant for you:
https://www.homebrewtalk.com/f163/d...tarter-then-why-not-farm-yeast-freeze-269488/

https://www.homebrewtalk.com/freezing-yeast.html

If I can remember correctly, the TLDR is:

7.5% glycerin/yeast slurry performed best.
Cool slow if possible, left for 1-3 days in a fridge then in the freezer in an iso-propol bath to buffer cooling.
Use froze free if possible, if not use gel packs / insulation.
Thaw rapidly in 37C hot water, tip off solution.
Pour in an overnight starter.

I think I read the slow cooling has something to do with a build up of trehalose to protect the yeast, I've only seen in one other place the question asked whether or not it is possible to add it to the solution itself but it hasn't been answered.

(tested for up to 15 months storage).