Sunday, November 6, 2011

Sunday Night Update

Before I delve too far into the wine making process, I must give a shout out to the book Techniques in Home Winemaking by Daniel Pambianchi.  Winemaking on a nano scale is much different than the way the big guys do it and Daniel's book is not only a great guide but also very educational for the beginning wine maker.  If you are at all interested in making wine yourself, I highly recommend this book.  It is also important to point out that the process I'll be following is the general process for making red wine.  I haven't been brave enough to try white varietals yet... maybe a 2012 Purple Girl vintage?  At any rate, some of the steps I'll be following are only applicable to red varietals.  The first of these processes? Maceration.

Maceration is the process where the phenolic materials of the grape (that is the tannins, coloring agents and flavor compounds) are leached from the skins, seeds and stems into the must. Another wine term... must. Must is the juice of the grape before it has been fermented.  So, in simple terms - maceration is letting the  smooshed up grapes sit for a period of time. ("Smooshed up" is a Purple Girl technical term).  This process is what gives red wine its color since red wine grape juice is actually fairly grayish in color.  There are many, many different strategies on how to conduct maceration.  One strategy we are trying out this year is called cold soak maceration.  Technically, this is supposed to be carried out for several days to a week.  We are going to give it a couple of days since we aren't on our own pressing schedule.  And technically the must should be refrigerated to 46 degrees or lower.  We're just taking advantage of the bitter cold temperatures of my garage... which at the moment feels like it is a cousin to the Arctic.

This afternoon after we got the grapes home, we added 1.5 teaspoons of pectic enzyme to each 75 pounds of grapes. Pectic enzyme breaks down the pectins that occur naturally in the fruit.  That same pectin is often responsible for cloudiness in wine... not a desirable trait in even the cheapest wines.  The other side benefit to adding pectin is that we should get a higher volume of free-run juice at press.  (I'll go into free-run juice more in a later post but more free-run juice is a good thing).

After letting the pectic enzyme do its thing for four hours, we then added Potassium Metabisulfite (or KMS).  There are many reasons to add KMS. The first is to take care of the very unwelcome wild yeast that occurs naturally on most wine grapes.  Left to their own devices, these wild yeasts will take over and can result in some very unpleasant tasting wine.  Trust me... I did not know about adding KMS the first year I made wine and it is not something I'd like to taste again.  KMS effectively kills these wild yeast organisms resulting in a "clean slate" for our carefully chosen wine yeast we'll inoculate with later.  Second, KMS reacts during fermentation to become sulfur dioxide and is in both free and bound form.  Don't cringe... not taking you back to chemistry class entirely.  Free SO2 is important because it basically acts as a preservative. Without it, the wine is more susceptible to oxidation and formation of acetaldehyde.  To remind yourself of the unpleasant properties of acetaldehye, leave a glass of wine on the counter overnight and take a big wiff the next day.  You'll learn to appreciate sulfur dioxide's role in protecting wine during the winemaking process.

That's all for tonight... stay tuned for the big yeast inoculation.  Where the magic begins!


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