Yeast Harvesting after racking

[KTY]

I'm familiar with dumping the initial slurry until it turns creamy and collecting this until it turns powedery. But what about all the beautiful yeast left in the tank after racking? I'm dumping several gallons of beautiful slurry.

[dick murton]

Don't.

The yeast is likely to be atypical - that's why it hadn't flocculated as fast as the rest, in time for cropping for re-use. It will almost certainly produce atypical (generally slow) fermentations, with non standard flavours.

[rochefort12]

Reviving this old thread.

Does anyone go by their rule-of-thumb as to when yeast should be harvested?

What I've been doing for a long time would be to - harvest yeast a day before brewing(take a count) and feed it with wort - oxygenate it and pitch it the next day.

Would it be better to harvest the yeast 2-3 days after cold-crashing and storing it at 1-2C before prepping it for brewing?(feeding it with wort and oxygenating it)

I have tried the previous method and have ended up with yeast that fermented more aggressively. Any thoughts?

[Bull_MAC]

Actually just learned this. You want to store yeast between 2-4 deg C. Below 2 deg you risk the chance of freezing the yeast. Above 4 deg it can create alcohol toxicity, limited nutrients, depletion of glycogen, and less viability/vitality. You want to harvest it as soon as possible to avoid late yeast cropping. I'm not sure about the O2. I do know when storing yeast you want to limit the amount of O2 because it triggers the yeast to consume whatever glycogen it has and then produce lipids which you don't want. But if your adding the O2 with wort, I would assume the yeast consume the nutrients in the wort first. Then again, if your doing it a day before brewing, the next day wort will be oxygenated, so not sure if you are adding unnecessary O2 to the slurry.