Starter sizes from frozen yeast bank. What are your sizes?

[acidrain]

I've been following the frozen yeast tutorial by Brewitt. I have a small bank of yeast now, and I did my first starter from a Dennys favorite.
My sizes are: 50ml vials with 25ml dense slurry mixed with a 25ml of a 20/80 mix of glycerin/water for a final mix ratio of 50% yeast, 40% water, 10% glycerin.

My starter method is 2L of 1.040 wort on a sir plate with constant airation.

After 48 hrs, and crashing, I ended up with a very small amount of yeast (less than 1/4" on the bottom of my flask). The SG of the remaining wort is 1.030.

Should I be stepping up with smaller starters?
Should I let it multiply longer?
Brewers Friend says that starting with 20B cells, in a 2L starter I would end up with 308B cells.

Either I have way underestimated the starting cell count, or the viability of my yeast is way low.

What size starters/quantities of yeast are you guys using?
How is the viability of your frozen yeasts?

Keep in mind, this slurry was taken from a fresh starter, mixed and frozen slowly, and should have been quite viable.

 

[acidrain]

Simple question.. are you guys starting small frozen yeast samples in 2 liter starters?
How long are you fermenting those?
How much slurry are you getting?

 

[bja]

Simple answer... I would start with a 1/2 liter starter then move to a 2 liter.

 

[acidrain]

Simple answer... I would start with a 1/2 liter starter then move to a 2 liter.

OK, cool.
Are you reviving frozen yeast specifically?

Anybody else reviving frozen yeast?

 

[JackRussel]

I have not started my yeast bank yet, but here is a post about stepping up a 6ml yeast starter. https://www.homebrewtalk.com/f13/guide-making-frozen-yeast-bank-35891/index72.html#post5422216

 

[acidrain]

Thanks for the link... good read.
I didn't really get the number of responses I thought I would on this subject. Since posting this I have learned about stepped starters.
Liker I said in my original post, my samples are frozen from 25 ml dense slurry mixed 50/50 with a 20% glycerin/water mix, which leaves a 10% glycerin/yeast mix.
When needed, I pull one and warm it fairly quickly and do a first start with 800 ml wort (constant air and stir plate).
Crash/decant that step, and make a new one in two liters wort.
This gives me more than enough for 6 gallon fairly high gravity batches. Works like a charm!

 

[el_caro]

I usually start with 150ml starter then 500ml then 2L
Works well for me.