Estimating Yeast Amount

[keyman]

Can anyone tell me about how many billions of yeast cells I have if I have a 25 mL vial of "Yeast Cake"?

 

[Mojzis]

MrMalty.com

It depends on age, amount of yeast compared to trub, etc. There is an option on mr malty to give you an estimate.

 

[keyman]

MrMalty.com

It depends on age, amount of yeast compared to trub, etc. There is an option on mr malty to give you an estimate.

I guess I am not the sharpest tool in the shed when it comes to using these calculators. I looked at the repitch from slurry and the other sections of this calculator. I have a 50 mL vial that I have made a mini starter. It has been in the fridge to crash a few days now and I want to figure out how much yeast (in Billions) cells I have. I have about half the vial (25 mL) of a solid yeast cake. The rest is clear liquid. I started this starter from a petri dish and stepped it up 3 times to get this amount of yeast. I just can't figure our how to estimate the cell count using that program. Maybe I'm going at it all wrong but I sure would appreciate the help.

 

[Mojzis]

Go to the site. Then click yeast tools, then click yeast pitching calculator, click on tab that says re-pitching from slurry, and enter your info. Looks like you may have close to 100 billion cells. The only way to be sure is to do a cell count with a microscope and stain for viability.

Alternatively you could make a 1L starter from what you have and pitch that into the ale assuming normal gravity and 5 gallons (or just use the calculator to see what you need). That way you will know you have the perfect amount of healthy yeast.

I would read this page also:
http://www.mrmalty.com/starter_faq.php

If you have more questions don't be afraid to ask. We all were starting once also!

 

[diS]

You can try to estimate cell count based on Wyeast instructions:
http://www.wyeastlab.com/com-yeast-harvest.cfm

All you need is one test vial.

 

[el_caro]

My method is to work on 3bn cells per Ml of compact yeast. I only harvest yeast from initial starters and hence there is little non yeast material in the vial.
Therefore my assumption would be 75bn cells in your 25ml if it was carefully washed.

When I go to make a starter I then use YeastCalc to guide me.

I would input the 75Bn and the date I harvested it from the starter and the calculator will give you an initial viable cell estimate and guide you from there in starters required.

 

[keyman]

My method is to work on 3bn cells per Ml of compact yeast. I only harvest yeast from initial starters and hence there is little non yeast material in the vial.
Therefore my assumption would be 75bn cells in your 25ml if it was carefully washed.

When I go to make a starter I then use YeastCalc to guide me.

I would input the 75Bn and the date I harvested it from the starter and the calculator will give you an initial viable cell estimate and guide you from there in starters required.

This yeast was not washed. I harvested it from a bottle and applied it on a petri dish and grew a colony of cells. I then collected the healthiest and made a little mini starter. I did this 3 to 4 times to grow the yeast to the 25mL of solid yeast cake. I thank everyone for they’re input and will use the estimated 75 to 100 million cells as a base. This will help me keep track when I am learning this process. Your help was appreciated.