Cell Physiology Lab has probably been the most exciting and interesting lab I’ve ever had at Franciscan. In lecture, we study the cell. The lecture portion is really intense: it’s a 400 level course and we just fly through complicated material every class. The lab portion is essential and we take what we are learning in lecture and get to see it happening right before our eyes. It’s awesome!
This week, everyone in lab was excited because this week was extra special: we were going to make beer. Brewing beer requires fermentation, or converting simple sugars to alcohol. Typically, you use yeast to do this and in an oxygen free environment. My lab group (photo above) decided to make “Irish Stout” beer—we got to pick out the style of beer a couple weeks ago out of a catalog. The kit came with a “malt extract,” which provide the bulk of the fermentable sugar, the specialty malted barleys that are particular to the style we chose, hops for bittering, flavor, and aroma, and the yeast which turns the resulting liquid (called “wort”) into beer.
How’d we do it? Well, we crushed the specialty malted barleys and we put them in water for 10-30 minutes at 155 degrees fahrenheit. We took it off the heat and added the malt extract, brought it back up to boil and added the hops. We cooled it down with some ice and water (5 gallons!), and now we have that “wort,” which only needs yeast and time for the yeast to do its fermentation thing. We added the yeast and put it in a big white container and sealed it off from oxygen. Now, we wait two weeks to allow fermentation to occur.
Fermentation occurs when yeast converts simple sugars into ethanol. The “nitty gritty” is that glucose is converted to two pyruvate molecules, carbon dioxide is removed from the pyruvate to form acetaldehyde by an enzyme in yeast (pyruvate decarboxylase). Then, the acetaldehyde is reduced to ethanol by another enzyme (alcohol dehydrogenase with NADH). So, you end up with the main product of ethanol, with some carbon dioxide and ATP (energy) on the side. Who knew?
I have high hopes for this Irish Stout brew. Definitely excited! Usually you never want to drink anything in the lab, but this is an exception.
And we have a bit of friendly competition: another lab group made Autumn Amber Ale by using a different set of specialty malts and slightly different hops.
Since I’m of legal age, I’ll definitely be sampling both!