Help - yeast starter from slurry

[Griffin495]

I'm going to be brewing an American Amber Ale on Monday. 2.75 gallon batch at 1.048. I'd like to use some unwashed yeast slurry that I have stored. I understand how to make a starter, but I can not figure out how much slurry to use even after hours of research.

I'd like to use some WLP001 that I used on a previous batch of amber but it was harvested on 7/29/18. I've got about 230ml (8oz) of it and it was used on 2 prior batches of beer. I can't figure out how much of it to pitch into a starter. Or what size starter for that matter.

In addition, I have these other slurries (but I'd like to use ^ one if possible):

WLP001 350mL (12oz) from a cream ale harvested 9/8/18 used 3 times prior
WLP001 710mL (24oz) from a Sierra Nevada Pale Ale clone 10/21/18 used 3 times prior
US-05 350mL (12oz) from a blonde ale 12/9/18 used 1 time prior (don't really want to use this one)

I looked at Mr. Malty and for all the WLP001, if I did a straight pitch, it would take 426ml of slurry, but I really don't think that is the best approach to take (nor do I have enough of the first two yeasts) and would rather go with a starter to get this batch going.

And before anybody mentions it, I don't have time to go to my local home brew store to get fresh yeast so that's out.

Any and all help would be appreciated as I just can't figure this out even after looking through this forum and other places online.

Oh...and Mr. Malty tells me I need 93 billion cells while BrewersFriend tells me I need 95 billion cells if that helps

 

[Griffin495]

Anybody? I am planning on doing my starter tonight and would love some help. On another forum, I saw mention of just adding a tablespoon of the slurry and that would be enough. Thoughts?

 

[Abrayton]

500ml vitality starter. Pitch into cooled wort at high krausen

 

[Griffin495]

Update: Following some advice on another thread, I ended up making a starter. I made a 1 L starter of 1.040 wort and pitched in 4oz of WLP001 that I harvested on 7/29/18 on Thursday night and just intermittently shook it up. It took a while to get started, but did take off. On Sunday night I put it in the fridge. Monday was brew day, so I pulled it out and decanted it and pitched about 1/2 cup of slurry into 2.75 gallons of Amber Ale at 1.046. I checked on it later that night and less than 8 hours later it was bubbling away through the blow off tube into a mason jar of sanitizer. I've never had one take off that fast. This morning it had a nice healthy head of krausen. So it looks like it worked, only time will tell.