The Smell of Yeast

For the home winemaker, there is no finer aroma then the smell of wine during fermentation.  For everyone else, it is a rank stench indeed.  Opening the door to the downstairs basement releases vapors that by all accounts I should never have expected my gracious wife to allow me to bring into the house, yet there it is nonetheless, and with only the smallest of complaints. 

As the yeast converts the sugar to alcohol it off-puts carbon dioxide and other gases.  To allow these gases to be released from the carboy, while keeping out oxygen which could ruin the wine, we cork the carboys with airlocks.  The airlocks I use have three plastic pieces, one of which holds a small amount of water.  The released gases move up the carboy through a hole in the cork and into the water, lifting up a second piece of plastic as the pressure builds, and finally exits the carboy through small holes in the plastic cap on top.  In addition to the hideous (I mean lovely) smell, the airlocks provide a great way to confirm that the fermentation is in process, because at full steam the middle plastic piece will bob up and down on a regular basis as it releases the gas.  Mine is currently popping at about once a second, which means at this rate I should have fully fermented wine in a matter of days.  In the meantime, the two glass carboys look like a lifetime supply of the muddiest, fizziest Sprite you’ve ever seen.  Yummy!