Yeast Starter for 15 Gallon Batch

I want to attempt a 15 gallon AG batch but I'm curious about the yeast. I have a 2000ml flask. Can a single Wyeast smackpack or White Labs vial make a big enough starter? Also I would be primary fermenting in 2 different vessel's. The OG will be around 1.055. Would that pose some issues?

I'm assuming this is for an ale. If you're splitting the batch into two separate vessels that's 7.5 gallons of wort per vessel. Mr. Malty says you'd need 2.68 liters of starter, or 288 billion yeast cells, per 7.5 gal vessel @ OG of 1.055.

If it were me, I would treat each batch separately and just get two packs of liquid yeast and two 1-gallon growler bottles to make two separate 2.68 liter starters. In other words, one starter per batch of beer. Be aware you'll need to step up the starters gradually to your final volume requirement... there's plenty of info in the forums here on how to accomplish that.

Another option is to use dry yeast. You'd need approx. 1.4 packets of dry yeast per vessel if you go this route.

It may also be a good opportunity to test out different yeasts in each vessel, say Wyeast in one and White Labs (or whatever you choose) in the other.

I do 15-20 gallon batches quite frequently, and I can tell you that a single smackpack or vial into 2000ml isn't going to cut it. You didn't mention if you are doing an ale or lager, but for lagers I typically do 4 vials into a 5000ml starter and for ales around 2-3 vials into a 3000-4000 ml starter. Check mrmalty http://www.mrmalty.com/calc/calc.html and punch in your beer specifics to see what size starter you should be making.

My bad. It's an ale. And it would be 10 gallons in one fermenter and 5 gallons in the other. I did a 1.065 ale with a 2000ml starter and got great fermentation out of it. Just wasnt curious how that would fare out. I will probably buy 2 packs to use.

Size the starters appropriately for the batch size their going into... You'll need a larger starter for the 10 gallon batch, compared with the 5 gallon batch.

IF you have a stir plate, use that at least for the 10 gallon batch starter. It will reduce the size of the starter you need to make. With a stir plate, the 10 gallon batch only needs a 3.38L starter. Without a stir plate (using a simple starter) you'll need a 9L starter. IMO, that's reason enough to get/make a stir plate and use it...

Got a stir plate actually. One of the best things I've bought so far.

busta98 said:

Got a stir plate actually. One of the best things I've bought so far.

Click to expand...

Then it's just a matter of making a couple of starters and going to town... Make a 3.5L starter for the 10 gallon part, and 1L for the 5 gallon piece and you'll be rockin in style. So, two packets of yeast, and you're done.

I'm really looking forward to using mine for the first time... Would you hit the starter with some pure O2 before putting it on the plate, or just use the plate??

Just use the plate. I've done several starters and never had to do it. I used the plate on my 1.065 IPA batch and got 85% apparent attenuation from it from Wyeast 1056 american ale strain. I've got the Northern Brewer stir plate.