How to calculate multi starter for slurry?

Doing multi step starters with yeast packs has helped me alot. But, I would like to know how to do with slurry? I have month old US-05 and am gonna brew 10gallon batch next weekend. I only have 300mls and need almost 600mls slurry to make it work. I was going to guess and do a 1qt starter then 4 days later do a 3 qt starter and figured that would suffice? Anyone help me with this one?

I've been asking this question and can't really get a straight answer. I just play with the yeast calculator until I get some sort of logic that works in my head and then I go for it.

I'm thinking you may be able to go straight to a 3L starter. Put it this way: with an average gravity beer (1.050-1.060) and a yeast packet with "average age" (let's say a month old), you generally need to almost double the amount of yeast. Usually this means making a 1-2L starter. Your stats sound about the same, so I'd say you need to make a 3-4L starter with the yeast you have. Forget the step up.

Here's a thought process that might help: It sounds like your yeast is slightly older (a month or more?) so the calculator is spitting out 300mL for each batch. Remember, though, if you make a starter, you get to reset the viability back to 90-100%. So check to see how many mL you need of yeast if it were freshest. That's how much should be on the bottom of your flask after you make the starter.

I can run this through with you.

You're saying you need 600mL of month old slurry which I'm assuming you calculated from MrMalty's Pitching Rate Calculator (PRC for short). Just so I could use some numbers, I'm assuming you plugged into the slurry option: 10 gallons of a 1.088 Ale with month old slurry. That gives 597 Billion cells needed or 597 mL of your 46% viable month old slurry.

If you play with the numbers in the PRC, you find that when your 300mL of slurry was 100% viable, it had 652 Billion cells. You only have 46% of that which is 300 Billion cells.

Go to the Liquid Yeast tab and enter 300% for viability (since a 100% viable tube has 100 billion cells on average). Enter your other numbers (1.088, 10 gallons) and make sure the "# Vials or packs needed with starter" shows 1 and you get a 2.11 Liter starter required.

You're my hero... I KNEW there had to be a way to use the calc to figure this out.

I'm sending you all my beer in thanks. It's in the mail.

I'll PM you my address

That is great!! Thanks