Start of the New Wine Season and Making Red Wine

Sample of Estate Grapes

For this year, 2012, August 26^th marks the beginning of my new wine year.  So, on this day I picked my grapes which are a mixture of Merlot and Cabernet Sauvignon which will produce this year's Estate Wine.  I got a total of four bushel size containers of grapes.  I promptly crushed them, removed their stems, and placed them in a 75 liter plastic barrel that serves as the primary fermentation vessel.




Packets of Dry Wine Yeasts

Once in the primary fermenter I did a sugar analysis of the grape juice and removed about one quart of the must which I boiled, let cool to room temperature, and added one 5 gram packet of dry Pasteur Red yeast, a wine yeast.  This mixture of wine yeast and boiled, cooled must is called a yeast starter.  After about 12 to 14 hours, this starter was foaming with the yeasts actively converting sugar in the must into carbon dioxide gas (hence the foaming) and alcohol.  I poured the yeast starter into the primary fermenter, thus inoculating the must with the Pasteur Red.

Boiling Must to Which one Packet of Pasteur Red
Will be Added When Cool

I can not afford to let too much time pass once the grapes are crushed before I inoculate the must.  In my case, there are three reasons for this.  The outside skins of the grapes are covered with wild yeasts and I don't want these wild yeasts to have much of an influence on the quality of the wine produced.  The temperatures that I work at in this warm climate are high, usually above 25^oC, and at these temperatures yeasts are very active.  Finally, I do not use sulfites in my wines; sulfites are added to musts to destroy wild yeasts and other microbes.  Over the years, I have found that if no more 10 to 24 hours pass before inoculation of the must, wild yeast activity is low and insufficient to compete with commercial wine yeasts that I use.




A Refractometer

Using a refractometer I did a sugar analysis of the must along with three water dilutions of the must.  A refractometer measures the sugar content of grape juices.  It is easy to use, but the largest source of error using the instrument is incurred when the temperature of the measurement is not also recorded.  As it turned out, all of the readings using the refractometer occurred at a temperature of 28^oC, and I found the sugar content to be 23.6% by weight, which gives a potential alcohol content of about 13.4% by volume.  I will say more about using a refractometer in a later blog.

Mixing the Must in a Primary Fermenter

Once the must is in the primary fermenter and inoculated with yeast, it is necessary to mix the must well at least one time each day.  Primary fermentation is active for about 7 to 10 days.  After that length of time it slows considerably as shown by the lack of foaming upon stirring, and it is at this time that the must must be transferred to the secondary fermentation containers.