I had the pleasure of attending a yeast class taught by Andrew Wilkes, the Crooked Crab brewer, at Maryland Homebrew (MDHB).
Chris Anderson of MDHB highlights the class’ topics as:
- The benefits of yeast slants & plates
- Required equipment/ingredients for culturing your own yeast, and the best sources
- Sterile lab techniques at home
- Lab safety
- How to pour slants and plates
- Streaking plates and slants
- Growing yeast from plates and slants
- Calculations & assumptions for proper pitch rates
- Commercial Brewing Yeast Management (Show & Tell)
For 12 years, Andrew Wilkes specialized in Nuclear Engineering for the US Submarine Service. In 2008, he got the homebrew bug, eventually leading to working for 5 breweries. Currently, he is the brewer for the brewery-in-planning Crooked Crab Brewing Company.
Sterilization, we learned, can be achieved with a pressure cooker. Sanitization kills most bugs, but sterilization, which kills 100 percent of the organisms, should be used for cultivating yeast.
Andrew showed us how to make “plates” (Petri dishes) and “slants” (test tubes) of yeast. Make a wort jello from dry malt extract (DME) and agar (marine algae thickening agent). Pour your liquid jello into your dish or tilted tube, allow to cool and you have a culture medium that will keep for 6 months. Slants are usually made from plates or other slants to isolate a desirable colony of yeast. A desirable colony of yeast is, as Andrew describes it, a Goldilocks colony – not to too big and not too small, just right.
To streak, use an inoculating needle to collect yeast from your source to the plate or slant. He suggests putting it in the oven with the light on (about 80 degrees) for 2 days. Check it after 24 hours – the yeast should be growing. If not, toss it and start over. After 48 hours, tape it up with electrical tape and store in the fridge for up to 6 months.
We had a chance to smell the banana, clove and spice esters from a Belgian yeast plate. It Reminded me of a hefeweizen.
To start a batch to pitch, allow about 6 days for a 5-gallon batch. Pull some of the colonies from a slant (preferred) or plate and add to a tube with wort. Put in the oven for 2 days. Pitch to a bigger beaker (10 times the size) and repeat. Repeat into a bigger beaker (again, 10 times the size). Pitch and witness the magic of beer making with your own captured yeast.
Here is an inoculating plates and slants site that gives a detailed explanation of yeast propagation.
At the yeast class, I met the Crooked Crab owners – Earl Holman, Dan Messeca & Alex Josephs. They all met at the University of Maryland College Park. They plan to open sometime this year in Odenton near Ft. Meade on Telegraph Rd. Their 15-barrel brewery is still under construction.
I was lucky enough to try 2 of Andrew’s beers: a nice coffee stout and cream ale with a faint taste of sweet cherries. Both were very good and will be featured at the Crooked Crab. I look forward to their opening.