Yeast Ranching notes

These are some notes I took when the owner/brewer of the soon-to-be-opened Kelsey Creek Brewing gave a seminar on yeast ranching to some members of the Lake County Homebrewers club.

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To grow and cultivate (aka “ranch”) yeast you want clean clear wort with the trub precipitated out to mix with agar to put on the petri dishes. You will also need inoculation loops and  inoculation needles.

Required for yeast ranching:

• agar
• wort with a specific gravity  of 1.030-1.040
• A pressure cooker (which will get up to ~235F)
•  isopropyl alcohol (70)
• Petri dishes (these are cheap)
• inoculation loop
• inoculation needle
• Saline solution ( the type for contact lenses is sterile and it’s cheap)
• some known yeast to put on the petri dish

Process:

Sprinkle agar over the top of the cooled wort. Do not dump the agar rather sprinkle in around (7g/250ml). No need to stir. Sanitation is not critical yet, since it will go into a pressure cooker which serves as an autoclave. Be sure to add nutrient to your wort.
After it has been used, every time you touch something in the pressure cooker you spray it with isopropyl 70 alcohol.

Pour the agar & wort solution using the “pacman” technique
Make sure the agar sets up ~45min before flipping over to lessen the condensation

Place a drop of diluted yeast solution on the dish with the agar. Then remember the spot and drop sterile saline on the yeast’s spot.

Then use the needle to drag the drop to streak it.

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Nice to haves:

• Hemocytometer (local veterinary offices may have these lying around)
• microscope

To check yeast viability a bulb flask is used (9 ml of sterile and 1 ml of yeast and 1 drop of methylene blue) and .0001 ml of of solution is placed on hemocytometer slide

Resources:

• Yeast: The Practical Guide to Beer Fermentation by Chris White & Jamil Zainasheff
• The Practical Brewer : a manual for the brewing industry by Harold M. Broderick, Master Brewers Association of the Americas

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• Ungrateful yeast (52beers.wordpress.com)
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• This Week in Brew Disasters: Big Irish American Red Ale follow-up/Taste and Specific Gravity (52beers.wordpress.com)
• How to Homebrew Beer (answers.com)
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