Firestone Walker's Jim Crooks Yeast Pitch Formula

During my 2007 Road Brewer trip, I spent a good bit of time at Firestone-Walker Brewery with Lab Manager Extraordinare, Jim Crooks. I asked Jim if he had one piece of advice for small and brewpub brewers, advice that would increase the quality of their beers, what would it be. Without hesitation Jim advised that brewers could dramatically improve beer quality by accurately pitching the correct quantity of yeast. A big thank you to Jim for sharing his technique with my readers:

All calculations are done in Plato.

Required Equipment:

Microscope with 40X ocular
Hemocytometer
1:100 .85% saline dilution blanks
Methylene Blue solution
Hand held counter
1 ml pipets
Transfer Pipets
Test Tubes

Standard yeast pitching calculations dictate that for proper ale fermentation there will need to be 1.0 X 106 (1 million) cells per milliliter of wort per degree Plato. It has been stated that Lager brews would require 2 times the yeast of an ale brew of the same starting O.G.

Most yeast slurries require dilution for ease in cell counting
Follow normal yeast counting procedures A decent example can be found at http://www.whitelabs.com/beer/cell_count.html.

In order to not appear to favor one yeast supplier over another, here are links to Wyeast and Brewing Science Institute's webpages on yeast pitching:
http://www.wyeastlab.com/pitch_rate.cfm
http://www.brewingscience.com/pitching_rate_calculator/pitching_rate_calculator.htm

To use Jim's interactive Yeast Pitch Rate Chart you will need the following information:

~ Original gravity of the brew to be pitched
~ Barrels of wort to be produced (gallons can be converted to barrels by dividing gallons by 31)
~ Density of yeast slurry (cells per ml found using microscope counting procedure)
~ Viability of yeast slurry (total cells counted minus dead cells which are stained blue/divided by total cells)

Here is a link to Jim's interactive Yeast Pitch Rate Chart. You must have Microsoft Excel installed on your computer, and you must enable Macros when the question pops up. Just plug in your numbers. The chart is set up to be a really simple tool to give an understanding on yeast pitching volumes.

Enjoy,

Jim

Jim Crooks
Q.C. Manager/Microbiologist
Firestone Walker Fine Ales
Nectar Ales