Yeast Starter & Slurry Newbie Questions

[robuck]

I'm planning to brew a stout that will be a 23L (6.08Gal) batch at ~1.092OG.

I saved some (Irish Ale) yeast slurry from a previous batch of 4.7% stout in mason jars and I've been trying to figure out what to do with it. I've read about starters and did calculations, but I've never re-used yeast before so I'm not very confident.

I used MrMalty's calculator which said I need 378 billion cells, 185ml of slurry.

I made a starter in a 1gal glass carboy using 200g Light DME, 2L of water, and the old refrigerated slurry that was in the bottom of two mason jars. It's been going for about 24 hours.

Is that going to make enough yeast to get to 378 billion, or will I have to do something else?

 

[khawk95]

I would use a calculator to determine pitching amounts. I like this one.
http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/


Roed Haus Brewery

 

[robuck]

Thanks for the tip, nice calculator! I tried filling it in and attached an image, does this look about right?

I set the yeast density to 2.4 because that's MrMalty default density. I'm not sure if I was I was supposed to leave it at 1bil/ml or not.

Going by the pitching of 0.75 and MrMalty I'll have enough cells (392bil/ml), but since this imperial stout is high gravity, should I do the extra work of doing a two step starter? That would bring the gravity to 633bil/ml which is about a Pro Brewer 1.25 pitch rate. That seems like a lot more yeast than MrMalty recommends.

 

[khawk95]

With that high gravity, I would go a two step starter to be safe.


Roed Haus Brewery