Starter with Dry Yeast

[RLinNH]

Great work Bobby_M!!!

 

[Sir-Brews-Alot]

I think it mostly has to do with the OG of your wort. If there are enough yeast cells to ferment the beer, without the need to reproduce, then oxygen may not be required. BUT if the yeast do, in fact, need to multiply, then oxygen is most definitely needed. Which would support the idea of needing to oxygenate high gravity wort, but not low gravity wort.

The best idea is to just use Mr. Malty and figure out exactly how many yeast cells your wort needs and make your decision based on that. A 1.048 gravity ale, fermeted with dry yeast with 90% viability, requires 177 billion cells, which is a little less than a 11.5g packet of dry yeast(~200 billion). In that situation, pitching the entire packet, you would not need to oxygenate.

 

[ChillWill]

The dry yeast will reproduce without oxygen.

I think the idea to oxygenate 14 hours after pitching on a high og beer is excellent. Although when I do a big beer I like to use loads of slurry, ideally washed as you should get better attenuation from the yeast selected from this method (as the lazy floccy poop should fall out with the trub in the washing process).

But also you suggested, pitching to Mr malty figures is a good practice the majority of the time.

 

[rellot]

Looks like we have the classic contest between conventional wisdom vs experts (well Bobby M is not an expert, but his experiment is convincing).

facts can't persuade those who already know the truth.

 

[dogbar]

For some reason I can't watch the Bobby M video on my phone, but if active fermentation starts earlier with the nonaerated batch, then wouldn't the experiment again suggest that oxygenation matters? The lag phase, prior to active fermentation, is when the yeast are reproducing. If that lasts longer in the presence of oxygen, then either it's taking longer (plausible?) or you're seeing more rounds of reproduction, and thus a higher cell count (of healthier yeast, seems to be the gist of passedpawn's other link).

 

[Progfan2010]

John Palmer says to aerate the wort before pitching. And he never mentions either Dry or Liquid yeast.

 

[Andynewbom]

anyone used dry yeast and a stir plate to GROW the yeast? we do NOT have the ability to go buy yeast living in El Salvador, so we want to take one packet 11.5 grams of a safale yeast and 4x it using stir plate starters. it SEEMS that there is enough lipids to go 3-4x in each packet and since we need about 800B cells and each packet has about 200 B cells we need to 4x it cell count wise. our thought is this: do a smaller starter with the dry yeast and double it, then double that batch again to get to 800B cells and about 2-3 liters. we are trying this out but any thoughts on the concept? are we on the right track or stupid? we do not have any liquid yeast, cant buy more yeast easily and need to BOTH conserve yeast packets AND make a 70 liter batch. We will begin yeast farming after this. now that we have two stir plates and temperature controlled ferm chamber

 

[rellot]

shouldn't be a problem. i think the usual debate is whether or not to make a starter or add another package. The cell count in 11.5 grams is higher than in the usual liquid yeast container.

But if you just need more cells, propagate away. I don't know how big a starter to use though. Wyeast says if you take their smack pack (100 billion cells) and use a 2L starter, that will double it. So for 11.5 gram dry (20 billion per gram or 230 billion), I would think something like 1 gallon would double it. I don't know if wyeast means with our without a stir plate, though. That would make a big difference.

Mr. Malty says for 70L at 1.048 you need 623 billion or three 11.5 gram sachets. So I don't have any clue really how big a starter you need, or how much to step it up to. I guess I would just keep stepping it up and use the "repitch from slurry" button on Mr. Malty's calculator until you get enough.