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Wild Yeast Isolation

2,396 bytes added, 23:25, 11 August 2018
added David Thornton's "Yeast Bootcamp" section
===Storage===
Slants are a good option for longer term storage (3 months to potentially 2+ years). For instructions on how to make slants at home capable of storing any microbe for potentially 2+ years, [http://suigenerisbrewing.blogspot.com/2015/11/easy-home-yeast-banking-and-video.html see Bryan's video on Sui Generis Brewing (requires a pressure cooker)].
 
==David Thornton's "Yeast Bootcamp"==
This method was developed by David Thornton of [[SouthYeast Labs]] and [https://carolinabauernhaus.com/ Carolina Bauernhaus] for collecting wild ''Saccharomyces'' yeast and lactic acid bacteria. David described his method in detail on [https://www.milkthefunk.live/podcast/2018/6/28/episode-005-bio-prospecting-with-david-thornton-and-keston-helfrich-of-southyeast-labs-and-carolina-bauernhaus the Milk The Funk "The Podcast" episode #005]. The following is a summary of this process:
 
# Start with 75 mL of 6° Plato wort with yeast nutrient in a 250 mL flask. Add the sample (fruit, flower, bee, etc). If it's fruit, squish it up. Set the flask on a shaker or stirplate at 80-90F with a foam stopper (aerobic; aluminum foil should work too) for 12-48 hours. Look for frothing and as soon as that happens put an airlock on the flask, but keep on stirplate to assist fermentation.
# After the 24-48 hours, decant the liquid and leave the biomass at the bottom. Add new starter media that is 8-10* Plato with yeast nutrient, and purge the flask with CO2. Put an airlock on it on a stirplate and grow until the sugars have fermented.
# Again, decant the liquid and leave the biomass at the bottom of the flask. Purge with CO2, and add 20° Plato wort with yeast nutrient and an airlock, and place on a stirplate or shaker. Look for the wort to ferment down to around 2 plato or so.
# After the 20° Plato wort has finished fermenting, the liquid can be decanted, and the biomass can be streaked onto media to isolate the strains that have survived.
 
Agar that David uses (see also [[Laboratory_Techniques#Growth_Media|Growth Media]] on the wiki for other media types that might also be useful):
 
* Wallenstein labs nutrient: serves as a catch all.
* HLP: isolate ''Lactobacillus'' and ''Pediococcus''.
* LMDA: color indicators for acid production (then do a gram stain to see if it is positive or negative; ''Lactobacillus'' versus ''Acetobacter'').
* Lin’s Cupric Sulfate Medium: selects for wild ''Saccharomyces''.
 
Other notes:
* Measure pH to make sure it gets down to under 4.6.
* Generally this method selects for 1-3 strains of yeast with usually a lactic acid bacteria strain.
* The anaerobic nature of this method selects against mold growth.
* This method may not select for wild ''Brettanomyces'' since aerobic growth is limited.
==Growing and Testing Without Plating==

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