Did I Underpitch?

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Did I Underpitch?

  • I don't have a hemocytometer either, so I have no idea

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    2
  • Poll closed .

Jack Arandir

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Brewed a 10gal batch of Festbier today with 2 quarts of yeast harvested from an actively fermenting Pils last week. I don't have the ability to count cells, but seems like it should be a plenty large pitch. Here's my concern:

* In the jars, there was much less yeast than I expected: about 2mm of creamy sediment each.
* The Pils was still fermenting at 1.020 (I racked it to kegs to spund). So much of the yeast was still in suspension and had not settled at the bottom of the cone.
* When I dumped trub, I may have been too aggressive before harvesting the yeast. So I probably got less yeast in the harvest.
* The strain is WY2308 Munich Lager, a notoriously slow strain. So it'll be difficult for me to know if I actually did underpitch or if the yeast is just being its normal slow self.
* Based on a calculator I need 800B cells for a 10.75gal 1.052 fermentation.
* I plan to harvest and repitch this again for a second batch of festbier.
 
Last edited:
I decanted off about half the beer. It was extremely clear, so I think I got all the yeast into the fermenter.
You got all the yeast, yes, but there wasn't all that much.
Say, the settled out yeast contains 3-5 billion cells per ml. You'd need to pitch about 200 ml (!) of it to get around 800 billion cells.

Got any yeast ready to add, just in case?
 
Yes I have Diamond yeast I can pitch. That's probably the safest bet. It's just strange that I harvested so little yeast. I dumped a lot before harvesting because I didn't want to get a lot of hop matter into the pitch. Guess I dumped too much.
 
Yes I have Diamond yeast I can pitch. That's probably the safest bet. It's just strange that I harvested so little yeast. I dumped a lot before harvesting because I didn't want to get a lot of hop matter into the pitch. Guess I dumped too much.
It's a bit off a art (judgment) how much trub to dump, while at the same time keeping enough yeast behind. Is this a real conical or a brew bucket with a tapered bottom? Yeast tends to stick against the brew buckets' "cone" because the slope is not steep enough.

You could save out 3 jars when dumping:
  1. trub (+ some yeast)
  2. yeast (+ some trub)
  3. mostly pure yeast
Then use all or some of the 3rd, and if needed, enough of the 2nd to get your pitch rate.
 
It's a stainless conical - Spike CF15. I'm still tuning the processes, and yeast harvesting is one of them. Thanks for the advice - I'll try saving more jars this time. This beer is less hoppy so I'm less worried about hop matter in the pitch. What do you think about dumping trub midway through fermentation to improve the yeast harvest?

I pitched 2 packs of Diamond lager yeast for around 300-400B cells. I estimate the harvested yeast was around 200-500B cells, but it was fresh and healthy.
 
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