The big excitement of crush is long over and our first public weekend is behind us. So, what do winemakers do until the next harvest? Well, some of us (with employees) vacation on Ibiza, drink fabulous wines and flirt with the waitresses but most of us get down to the important work of making the wine.
Our red wines are finished with the primary fermemtation and are currently undergoing Malo-lactic fermentation, a process whereby a bacteria called Oenococcus oeni changes the tart acids (malic acid, like in apples) in the wine into the softer acids (lactic acid, like in milk). It's not really a fermentation in the strictest sense of the word but we won't pick nits. During this process the wine snaps, crackles and pops and gives off a little Carbon Dioxide as a by-product. You have to keep the barrels warm since the reaction is dependent on the temperature being above 64 degrees F and you usually have to inoculate the barrels with the bacteria in order to start things off. Some of the older barrels that have been through this process still have the dormant O. oeni living in them and when the wine is added the bacteria wake up and start eating. The ML process can last a week or up to 6 months or more, depending on the chemistry in each wine.
So we look, listen and taste and wait for the ML to finish. One sign that things are progressing is the smell of artificial butter. Diacetyl is the natural ketone is added to microwave popcorn and other foods to make you think you are eating the real thing. It's a natural by-product of the ML bacteria. Learning how to tell when ML is finished is a skill that winemakers learn. Of course you could always just send samples to a lab when you think it is done but that is expensive. If, however, you guess wrong and you find out later that it is not done then your ML will restart and CO2 will build up in the bottle and, BOOM! the cork pops and you lose.
Most white wines (like our Riesling) are prevented from going through ML so that they retain the tart acids that are characteristic of those grapes. It is a stylistic choice that the winemaker makes and we have all had those buttery Chardonnays that have gone through the process.
So, December and January are busy months for winemakers but in a more laid-back way. Meanwhile, behind the scenes, preparations are under way to get our labels approved by the TTB. We are also busy buying our bottles and corks in preparation for our first bottling project to happen in late January.
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