Harvested yeast from trub - what's potentially viable?

[sven945]

After bottling a Scottish Ale, I stirred up the trub and poured a litre into a sanitised kilner jar and put it in the fridge. It's mostly a kind of dirty brown, with a very thin layer of lighter stuff on the top. Have I messed up and saved mostly gunk, and only the top layer is half decent yeast? Or is it okay?

In future I'm going to harvest from starters, it's just that i didn't have a stirplate when I made this one, so I couldn't overbuild enough to make it worthwhile.

 

[Yooper]

It's mostly yeast. You have a lot there, probably enough for several batches.

I use a yeast calculator at mrmalty.com and you can adjust the amount of trub from a little to a lot if needed, and it still helps calculate the amount of yeast needed for a batch.

 

[sven945]

Cheers. My paranoia was that I'd only managed to save that tiny top layer!

I put hops in bags, and try to leave as much solid mass behind after cooling, when tipping into the FV, so I shouldn't have *too* much other material.

 

[flars]

The thin layer of yeast at the top is just the last of the yeast to drop out of the remaining beer.

The yeast cells will retain viability longer when stored under the fermented beer as you have done.

 

[sven945]

Thanks very much. I've seen other people's equivalent pictures and there have been distinct layers, so I was just after some reassurance that I'd not wasted my time!

 

[eric19312]

It's mostly yeast. You have a lot there, probably enough for several batches.

I'm curious about the quantity of harvested yeast to use and have also gone to Mr Malty but that 1-5 slider seems extreme.

I get too much brewing information off podcasts and for years followed something I heard on basic brewing which I believe was 1/2 cup trub and cake from a fresh batch for 5 gallons.

Recently I listed to Denny and Drew's Experimental Brewing podcast and was amazed that Denny was advocating using about 1/3 of the primary yeast cake for a batch of normal gravity beer and maybe half the cake for a strong beer. That is a lot more yeast than I've been using.

Yesterday after kegging I swirled up about 1.5 gallons of beer, trub, dry hops and yeast, and put 1/2 gallon into a 12 gallon batch. Fermentation started promptly

Will have to see how it proceeds, any ideas of what to look out for (off flavors?) if I have significantly over pitched? The yeast is now a 3rd generation of US05. Last beer was pretty big 1.070 OG and FG was 1.012 for attenuation of 82%