How to top crop yeast from a carboy.

[Bah]

The yeast at WL is packaged in the spent wort it was grown in. Before it got to packaging a given culture of yeast may have a few more sugars to ferment left in the wort, i.e. it was sent through QC before the gravity of the wort it's grown in fell to a minimum, but really not too many. There's plenty of deliberately placed, and naturally occurring nutrients in the malt that they use to grow it in, but there's no separate step/addition before packaging.

Besides wouldn't the liquid/beer that you're getting along with the solids be potentially still a source of nutrients since the beer you're top cropping from isn't fully finished? I'm pretty sure though that the viability would be higher, especially right away, and would deteriorate over time, just like in a fresh vial.



Brad Hammerson
Former WL Lab Technician
bradhammerson@gmail.com

[hopshead]

Here is another top cropping question: when repitching yeast from slurry, the general guidance is to repitch yeast from regular strength beers (i.e. its best not to repitch yeast from a double ipa for an Apa). Does top cropping yeast reduce the ill effects of high alcohol? My guess is yes because if you top crop the yeast, lets say 48 hours after pitching (when the beer is at high krausen), the alcohol wouldn't be as toxic (because it isn't completely fermented) at this point in time, would it?

[Bah]

Hopshead may be onto something, I was kinda thinkin about that too. Has anybody tried it/done an experiment?

[hopshead]

Well, I am finally committed to doing my own top cropping. When should I collect the yeast? Is there a general rule (i.e. what the krausen looks like or number of days into the ferment). Or, does it not matter when you top crop?

[ApresSkiBrewer]

Try to top crop the whitest fluffiest stuff... not any of the brown gunk (that has a cool german name I can't remember right now).

I agree that logically, you could harvest from higher gravity brews because the yeast hasn't been in contact or overly stressed by the alcohols yet... but the one thing that might still play a factor is high hopping rates (at least in ipa's iipa's and so forth).


On a side note... I've poured yeast from the bottom of my primary into an Erlenmeyer and kept it in the fridge for over 3weeks... and with a starter, had absolutely no issues.... and probably overpitched now that i think about it. My process was as clean/sanitary as possible... but far from a closed system - so just food for thought. Granted I didn't plan on keeping the beer around for 2-3 years, I knew it would be gone within 2 months.

[mattmacleod]

Try to top crop the whitest fluffiest stuff... not any of the brown gunk (that has a cool german name I can't remember right now).

"Braunhefe" I think (there or thereabouts).

[hopshead]

I top cropped yesterday and I think I got enough yeast to reuse. I'll make a bigger starter anyway to make sure:

[Bah]

I top cropped yesterday and I think I got enough yeast to reuse. I'll make a bigger starter anyway to make sure:

Awesome dude, let us know what you think of it, especially if you end up trying to go from a big beer to a small one after a couple generations or whatever.