Yeast havesting

I have been washing my yeast and it have been going fine but I was wondering when I should transfer to the secondary to get a decent amount of yeast. I usually have been waiting about 2 days after there is little to no activity on the air lock. My Gravity reading is usually with in 90-95% of what the final is. But on my last batch I did not get much yeast off the harvest and there is a ton of yeast in on the bottom of the secondary. Do I need to wait long? Is it just different yeast that takes longer to settle?

Thanks
Ryan

I'm not a big fan of harvesting yeast in a primary+secondary fermentation set up. Generally, you want to harvest a full diversity of yeast, and the two different yeast cakes in your primary and secondary will have different phenotypic characteristics. Primary yeast will be the relatively early flocculators, and secondary yeast will be the relatively late flocculators. When harvesting, you generally want a good mix of both to preserve the character of the strain.

If you are set on using a primary and a secondary, your best bet would probably be to do a longish primary and to harvest the yeast from there.

MalFet said:

I'm not a big fan of harvesting yeast in a primary+secondary fermentation set up. Generally, you want to harvest a full diversity of yeast, and the two different yeast cakes in your primary and secondary will have different phenotypic characteristics. Primary yeast will be the relatively early flocculators, and secondary yeast will be the relatively late flocculators. When harvesting, you generally want a good mix of both to preserve the character of the strain.

If you are set on using a primary and a secondary, your best bet would probably be to do a longish primary and to harvest the yeast from there.

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Agreed. I usually harvest yeast out of the primary after my beer has been in there 4-6 weeks, and make sure you stir/swirl the yeast cake well so you get ALL layers (the early flocs will be on the bottom, the later on the top)

I have only been harvesting from my primary. I usually transfer after about 1-2 weeks. I thought you did not want to sit on the yeast cake longer then you had to. How long would you recommend to let it sit.

Thanks for the response

MalFet said:

If you are set on using a primary and a secondary, your best bet would probably be to do a longish primary and to harvest the yeast from there.

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This is certainly contrary to commercial best practices where yeast is harvested very shortly after terminal gravity is reached. Why let it sit there and be subject to co2 and alcohol toxicity and continued metabolic activity in a nutrient poor environment?

If your reasoning were correct, wouldn't you also want to let your starters sit around for a month so you get more of the late flocculators (which are mostly petite mutants anyway)?

remilard said:

This is certainly contrary to commercial best practices where yeast is harvested very shortly after terminal gravity is reached. Why let it sit there and be subject to co2 and alcohol toxicity and continued metabolic activity in a nutrient poor environment?

If your reasoning were correct, wouldn't you also want to let your starters sit around for a month so you get more of the late flocculators (which are mostly petite mutants anyway)?

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Sorry, I should clarify: by "longish primary", I certainly don't mean a full month. "Longish" here is relative to what he is doing now, not relative to a primary-only system.

The OP says he is getting more yeast volume in secondary than in primary. If he is getting that much volume from petite mutants, something is very wrong with his yeast population. More likely, he's transferring when there is still a significant amount of healthy yeast in suspension, predominantly high attenuators. Ideally, he would harvest when the bulk of his yeast had settled. Pinning this to terminal gravity will work better for some strains than others (and for some fermentation configurations than others). Would you disagree?

In ad hoc experiments, I saw significant character changes from too-early harvesting in as few as two or three generations.

flyhigh said:

I have only been harvesting from my primary. I usually transfer after about 1-2 weeks. I thought you did not want to sit on the yeast cake longer then you had to. How long would you recommend to let it sit.

Thanks for the response

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The primary vs. secondary thing is a very dead horse, so rather than beat it further, here is a link suggesting that the yeast cake isn't so bad: https://www.homebrewtalk.com/f163/secondary-not-john-palmer-jamil-zainasheff-weigh-176837/

That said, there are still plenty of people who always use a secondary for a variety of reasons, so it's not a unanimous consensus.

THanks for the info MalFet and the link about primary secondary.

Would there be any problems harvesting the yeast of the bottom of the secondary if it has been there for 2 -3 weeks. total of 3-4 weeks since I brewed it.

Ryan

flyhigh said:

THanks for the info MalFet and the link about primary secondary.

Would there be any problems harvesting the yeast of the bottom of the secondary if it has been there for 2 -3 weeks. total of 3-4 weeks since I brewed it.

Ryan

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You pretty much never want to harvest from secondary. Primary is usually fine, even if you are doing a secondary. If you are getting a huge amount of yeast sediment in your secondary, though, that's generally a sign that it wasn't done dropping out and probably should have stayed in primary a bit longer.