Yeastie Beasties & Beer (Science)

I will now update you on my previous post on beer meets science. As you will know, I have been trying to isolate wild yeasts from berries with varying levels of success. Well, until I started touching blueberries! 

I dropped a bunch of blueberries into some wort, which led to significant fermentation. I then explained how I took this fermenting wort and used it as a starter to initiate a  fermentation in a larger volume in a "bottle" (my mini fermentation adventure). 

Figure 1. Image of me holding my precious bottle before fermentation. It has since given me the finger on many occasions.

Ever since starting fermentation in the bottle, I had seen significant and consistent levels of fermentation, evidenced by the bottle giving me the finger every morning when I checked (and released) CO2. It always told me to sod off by the time I was ready to go home.  Last Friday and after two weeks, in finally decided to take a sample (taste it!) and streak it out onto a solid wort plate. 

Figure 2. Wort taken from the bottle after fermentation for two weeks. It looked nice and clear, smelled great and gave me a definite alcohol kick!

Based on these results, i decided to streake out a little bit of wort onto a plate (with a smiley face as it was a friday afternoon after all!). I left the plate to incubate over the weekend at room temperature.

Figure 3. A smiling plate onto which i have streaked some wort. Nothing is visible (except for the smiley), but as they single cells in the wort suspension start to grow (and they cannot move on solid surfaces), distinct colonies should appear on the media surface... 

This (Monday) morning, I have found that indeed, my beer does contain Yeast-like organisms (based on the appearance of colonies and a quick look under the microscope. 

Figure 4. Evidence of growth on my plate! The whitish non-shiny appearance indicate the presence of Yeast in my collection. Shiny colonies may be bacteria. Tasting did not kill me though!

 

Now, I will have to isolate and grow individual strains (colonies) and test them for their ability to ferment and produce alcohol. Also, I would be interested to see how well these strains can tolerate higher levels of this lovely product of yeast metabolism.

 

Stay tuned!!