S.W. and Rich Hermansen
Guest Writers
wine@lbknews.com
Passing through the portal of Labor Day brings us to an interval neither summer nor 
autumn. Nights turn a little cooler as the daylight hours shorten. The afternoon sun often raises temperatures close to summer levels. Cincinnati led into the Labor Day weekend with a high of 94F degrees. The mountains of Montana closed out the last days of summer with an early snow.
Grapes in vineyards bask in sunlight leading up to harvest. Winemakers keep a close eye on sugar levels (brix) in wine grapes. Charting of increases in brix as the grapes ripen serves as a prelude to harvest. As brix numbers increase to approach target levels, winemakers begin a countdown to the start of the harvest.
The web even has an app that calculates an alcohol by volume estimate corresponding to a brix measurement or average of brix measurements and a conversion factor. The factor differs by grape variety, region, winemaker preferences, and other details. The conversion factor usually has a value around 0.6, so the app will show the value of 15 (% alcohol) for a brix of 25 and a conversion factor of 0.6.
Brix measurements continue after harvesting and crushing grapes as the grape juice, grape skins, stems, and seeds (must) ferments and reduces the brix of the must as sugars convert to alcohol. As fermentation reduces the brix, the winemaker watches for a target brix and estimated alcohol percentage. In the ideal case for a bone dry wine, the estimated alcohol percentage will approach the winemaker’s target and fermentation will have converted all available sugars to alcohol, leaving no residual sugar in the wine. More often a winemaker will stop or enhance the fermentation process to keep the al