When to add wort for yeast step up?

[Bugaboo]

Just starting to make ten gallon batches and also just made a stir plate. I'm planning on using a smack pack in two liters of wort and then adding two more liters to get the population up for two five gallon batches. I no-chill brew so my starters are made with real wort, so I'm not decanting the liquid then adding the cake. I simply shake everything up and add it all.

My question is when do I add my second two liters. At high krausen or after krausen and activity is done?

 

[MalFet]

Let the yeast build up glycogen reserves before the second dose and you'll get the most population growth. So let the starter wait as long as you can (up to 48 hrs) before adding the second batch.

And just out of curiosity, what does no chill have to do with not decanting? (Don't get me wrong, I've got no gripe with either no-chill or no-decant. I just don't follow the association you made between them.)

 

[jeffmeh]

I suspect his rationale is that it is the same wort as the brew, unlike making a starter in light DME for a brown ale.

Personally, if it is a big starter on a stir plate, getting oxygenated, with no hops, I would decant it rather than have it affect the taste of the batch. Alternatively, I would just oxygenate the starter wort before pitching the yeast, then skip the stir plate and let it ferment like a mini-batch, and pitch it into the real batch at high-krausen.

 

[MalFet]

I suspect his rationale is that it is the same wort as the brew, unlike making a starter in light DME for a brown ale.

Personally, if it is a big starter on a stir plate, getting oxygenated, with no hops, I would decant it rather than have it affect the taste of the batch. Alternatively, I would just oxygenate the starter wort before pitching the yeast, then skip the stir plate and let it ferment like a mini-batch, and pitch it into the real batch at high-krausen.

Ah, gotcha. The no chill gives him the time to use a beer's own wort. I've always given my starters a lot more time than that, but if you're planning to pitch at high krausen anyway the 12-16h is enough. I like your suggestion about aerating the wort and skipping the stirplate.

Not intended as a derail: I wonder if there have been any reasonably controlled studies comparing pitching at high-krausen vs. pitching after a cold crash. I've searched around a bit but haven't seen anything. My gut tells me to cold crash and decant to build up glycogen/trealose, but I don't have any real science behind that.

 

[jeffmeh]

Ah, gotcha. The no chill gives him the time to use a beer's own wort. I've always given my starters a lot more time than that, but if you're planning to pitch at high krausen anyway the 12-16h is enough. I like your suggestion about aerating the wort and skipping the stirplate.

Not intended as a derail: I wonder if there have been any reasonably controlled studies comparing pitching at high-krausen vs. pitching after a cold crash. I've searched around a bit but haven't seen anything. My gut tells me to cold crash and decant to build up glycogen/trealose, but I don't have any real science behind that.

I cannot help you with the biology, but from my reading and experience either method I outlined above works well. I do no-chill, and usually pitch at high krausen when using a liquid yeast. I have also missed the high krausen window and then decanted. I could not tell the difference, but that is hardly scientific.

 

[tomasej]

From the research I have done I would recommend to add at high krausen. Also, I have heard from some old salts that adding a drop of olive oil to your starter gives it oxygen. Like jeffmeh I have no scientific proof. Just tribal knowledge.

 

[MalFet]

From the research I have done I would recommend to add at high krausen. Also, I have heard from some old salts that adding a drop of olive oil to your starter gives it oxygen. Like jeffmeh I have no scientific proof. Just tribal knowledge.

Care to point to any of that research? I've seen plenty of claims to both sides, but none of it substantiated by other than anecdotal tests.

As for the olive oil, oh no not this war again! :cross: The master's thesis that first described using olive oil was interesting, but Kaiser and others made some rather sharp criticisms of its methods.

 

[Bugaboo]

I'm going to add my step addition of wort at high krausen. I'm sure that will work. Haven't thought about yeast life cycle since I've been in a particular routine. I know that yeast reproduce during both respiration and fermentation, so I would think both krausen and after krausen would be good. At high krausen is just faster.

To me olive oil seems like it would just kill your head retention.

 

[MalFet]

I'm going to add my step addition of wort at high krausen. I'm sure that will work. Haven't thought about yeast life cycle since I've been in a particular routine. I know that yeast reproduce during both respiration and fermentation, so I would think both krausen and after krausen would be good. At high krausen is just faster.

To me olive oil seems like it would just kill your head retention.

Yeah, I don't think there's any doubt that both approaches work fine. Just curious about any tests that might have compared.

The olive oil, whether it is a good approach or not, is supposed to be added in quantities of hundredths of a drop, so it doesn't kill head retention. There are plenty of other criticisms to be made though.

 

[tomasej]

Care to point to any of that research? I've seen plenty of claims to both sides, but none of it substantiated by other than anecdotal tests.

As for the olive oil, oh no not this war again! :cross: The master's thesis that first described using olive oil was interesting, but Kaiser and others made some rather sharp criticisms of its methods.

I'm not sure what your asking when you say "care to point to any of that research". Since my work isn't published I suppose you would have had to be standing next to me to view the results. As far as the olive oil goes I would not recommend it when your fermenting but putting a drop in your yeast isn't going to hurt retention. Just pour off a little of the beer when your starter is done and the oil which rises to the top will be gone. Again, I'm speaking from experience and have no scientific proof. When did we all become scientists all of a sudden.

 

[MalFet]

I'm not sure what your asking when you say "care to point to any of that research". Since my work isn't published I suppose you would have had to be standing next to me to view the results. As far as the olive oil goes I would not recommend it when your fermenting but putting a drop in your yeast isn't going to hurt retention. Just pour off a little of the beer when your starter is done and the oil which rises to the top will be gone. Again, I'm speaking from experience and have no scientific proof. When did we all become scientists all of a sudden.

As you like it sir. Didn't mean that to be a snarky comment. When you said "my research", I wasn't sure if that meant your own experimentation or your readings on the web. Either would have been what I was looking for so long as it involved actual controlled, comparative experimentation rather than just anecdotal experience.

Anytime you or I do a controlled comparative study, that's "being scientists", I'd say. Much of the major conventional wisdom of homebrewing have been subjected to controlled comparason at some point or another. The olive oil thing is a great example; I can't find the thread right now, but someone out there brewed 4 or 5 simultaneous mini-batches, innoculated them with different amounts of olive oil, and compared the results. Basic brewing radio just did a similar comparison of different speeding techniques, and the science section on this forum has dozens of other examples.

Not all this "research" is NIH quality, of course. Nor am I critizing you for not having done it; I certainly haven't either. But I don't think it's all that preposterous to say that controlled experiments on this topic _could_ exist.

Edit: found the olive oil experiment.