Stepping up from slants Q

[JonM]

Hey all!

I'm trying my first attempt at making a starter from a slant (1007 if you're wondering).

My plan was to follow the factor of 10 rule. I inoculated a vial of 15 ml of pressure-cooker sterilized 1.020 wort. Then I poured that into 150 ml of 1.040 sterilized wort in a small Erlenmeyer and put it on the stir plate. Following the 10fold increase idea, I should be able to put the 150 ml into any sized starter up to 1.5 L.

Here's the the Q: I have no idea how many billions of cells will be in the 150 ml step and, as a result, I can't accurately calculate the size I need for the final step up. I understand that the proper way to figure it out is to use a microscope and another device with a name I can't remember and do an actual cell count. However - is there a way to guesstimate the amount of yeast in the 150 ml step without doing an actual count?

 

[flugelizor]

I know this is a cop out, but simple answer is you are on the right track with 1:10. (assuming ale yeast).
Go 1:10 again to 1.5L. then 5 gallons
Is there a reason you need to know cell count?

You can work backwards.
What is the minimum proper cell count for pitching to 1.5L?
That's how much you have at 150ml at high kreusen .
I don't know that value off the top of my head because I just always follow 1:5 - 1:10.

 

[JonM]

I'm using 1007 so it's really not all that important that the cell count be precise, but I'm just curious for using other strains where pitching rate is important for ester production (3068, 1214, 002, etc. are some favorites in my collection.)

 

[dstar26t]

I started growing up from slants recently and do cell counts. What I observed the 2 times I've done it:

Looped from slant into 10mL sterile 1.020 then into 110mL sterile 1.020 gave 5.7 Billion cells. From there into 570mL 1.040 stirred then into 2.8L 1.040 stirred gave 348 Billion.

Looped from slant into 10mL sterile 1.020 then into 110mL sterile 1.020 then into 1L 1.040 stirred then into 5.1L 1.040 stirred gave 503 Billion cells.

All props were at 75F.

 

[JonM]

That's awesome! Thanks for the info.