My friend Robert Alan invited me to go wild yeast hunting with me the other day and of course I couldn't say no! Robert Alan works at local brewery and is fortunate to be given the task of hunting for yeast! Many breweries use yeast as a flavor component where as others simply use yeast as a fermenting agent, relying on their hops and wort as the major flavor agent. Our job for this adventure was to locate a wild yeast, local to this area that will highlight the terroir of the area. (Terroir or terre is french for "land." Essentially, it is a group of characteristics of a native area that impart a distinct attribute on local agricultural products). This yeast will hopefully be used for beer!
Yeast is a unicellular organism that changes carbohydrates like sugar into carbon dioxide (bubbles) and alcohol. Beer is just that, bubbly alcohol! Perfect! Let's get on with this adventure..
Being in the San Luis Obispo we are right in the heart of the Central Coast's wine region. After stopping at the brewery in Paso Robles for some yeast hunting gear (portable flame torch, sterilized wet swabs, and gloves) we headed west! Robert Alan has a family friend, a singer-song writer, who owns Poalillio Vineyards and welcomed us onto his estate so we could hunt some yeast! This was our view for the afternoon....
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| Real rough life.... |
After taking in the beautiful Paso Robles country side we trekked into the wilderness to gather the yeast....
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| Real rough conditions.... |
After randomly scientifically selecting the right sample vine, it was time for business
Using sterilized swabs in broth we were great scientists and made sure to follow protocol in the field. First we started with flaming the mouth of the tube (with gloves on!) in order to reduce cross contamination from the air and from us.
After flaming, we got right into the thick of things, literally...
We decided to harvest yeast from the skins of the grape as well as the grape vine stem. Yeast, as I was told, grows naturally in the microflora of grapes. Who knew!? Well, I mean, can't you just see it all over them!?
After repeating this a few times (Repetition is the science behind statistically reputable data!) we headed back to the lab in order to plate our samples.
Using a Schwarz Differential Agar plate and accurate precision, Robert Alan plated four samples of our harvested wild yeast.
After plating and carefully labeling our samples, we let them hang out in the cozy incubator and then we waited....
Update! Three days after our wild yeast hunt there was growth on the plates! (And I'm proud to say that the sample I harvested was one of the two that was showing growth. Yay!) Now we just have to hope that it a usable growth and not a bacteria-mold-yeast-fuzz cocktail growing on agar! *Fingers crossed!*
Update! Four days later....Robert Alan and the lab found usable yeast colonies!
Update! Five days later.... The usable yeast was mixed with wort (unfermented beer). And now the lab just has to wait for a lower degrees Brix and a lower pH (Brix measures the amount of sugar solids in a solution. So a lower Brix means that there are less sugars in the wort which means the yeasts are eating them! And that's a good thing. Remember when I said that yeast breaks down sugars and make by-products? Some by-products like carbon dioxide lower the pH. So a lower pH could also signify that the wort is being eaten by the yeast! Yay!)
I'll keep everyone updated on the wild yeast hunt! But look! We actually did some real science stuff! Woopie!
So until next time
Stay tuned! Stay hungry!
-Taryn Julia
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