Big Yeast Starter

[benbradford]

I am intending on doing a 5 gallon batch a day for 5 days and ordering everything this week for next. I would like to take 1 wyeast and make a starter and split it five ways for these 5 batches, one each day.

Should I just make a big yeast starter? 2 cups dme, 1 gallon starter for instance, pitching wyeast and fermenting and then splitting 5 ways and maybe adding some yeast nutrients to that to build count?

 

[joety]

As intuitive as it sounds, I don't believe a five litre starter produces five times the yeast as a one litre starter. Check www.mrmalty.com, but I'm guessing you'd have to at least double that or start with more packs/vials.

 

[Malticulous]

I think you should make a 2.5-3 gallon batch of 1.040 beer and repitch the yeast.

 

[Brew-boy]

MrMalty is the place to go

 

[joex444]

Well, you'll need around 1 trillion cells. Check this out http://www.northernbrewer.com/documentation/YeastPitchingRates.pdf

Looks if you use a stir plate, you can make a 2L starter then decant, add more wort and you'd be up to 1 trillion. Now, the calculations stop at 700 billion, so for the purposes of pure interest I went to Mathematica and fit the data. Turns out it goes like the square root of the second volume.

So, for a 1st starter size of 2L and a stir plate, you end up with the number of cells (in billions) as:
70.3 + 796sqrt(V), where V is the volume of the second starter in liters. Then to get 1 trillion, we need 1.36L as our second starter.

So 2L and then 1.5L should do it.

Without a stir plate, your equation is 41.4 + 470 sqrt(V), with a 2L initial starter. This would then require a 4.2L second starter. This is somewhat unfeasible. You might want to do a three stage starter, each 2L. This is an off-the-cuff number, I have no numbers behind it.

 

[joex444]

Also, if you don't use a stir plate, you could use two packs but you'd then need two separate 2L starter vessels. A two stage propogation of 2L, then 1L (in EACH) would yield ~510billion, combining them would work.

I'm not sure if you can simple combine two packs into one starter. I think with the sqrt dependence we're not going to have that trillion you want.

 

[joex444]

And just to totally go overboard, with a one stage propagation you would need around 40L = 10 gallons of starter. (This, for some reason, appears to go like x^0.6... if it is sqrt dependent then 50L = 13G).

 

[Malticulous]

I pitched 1 cup of slurry in a 1.066 IPA 24 hours ago and it's blowing off now. I guess I under pitched and should have checked with Mr malty?