Another Sonoma Wine Country Crush 

  To most the time of year from August through mid October is known as Harvest in the Sonoma Wine Country.  However around the wineries many refer to it as the Crush.  So what are those who call this time of the year Crush referring to?  Crush begins when the grapes are picked and continues through processing and fermentation until the last wine is safely in barrel. 

  Sonoma County’s 2014 harvest/crush season got off to an early start on Wednesday, July 30 at 10:15 p.m. with approximately 8 tons of pinot meunier grapes hand-harvested from Dutton Estate Winery.  This year’s start to harvest was one of the earliest on record.  After this early start to the 2014 season and moderate temperatures harvest wrapped early throughout the region.  Early indicators suggest tonnage appears to be larger than average over the past several years, but smaller than last year’s record-breaker.  The word is this year wineries are seeing tremendous quality.

  So what happens once the grapes are picked?  As the freshly picked grapes enter the winery, they have to be sorted for quality.  The grapes usually travel down a conveyor belt past the ever watchful eye of the sorters making their selections. The belt often vibrates to shake out bad grapes that might be trying to sneak in under cover of the good ones.  

  Once the best grapes have been selected, it’s time to crush them so the yeast can quickly get to work fermenting.  Modern wineries typically use large, automated crusher/destemmers, which break the skins open, exposing the juice and pulp, but without crushing the stems and seeds, which contain tannins. These compounds contribute structure and texture to wines but also are responsible for the sensation of astringency or bitterness. Destemmers can remove stems before or after the grapes are crushed, depending on the winemaker’s preference and the type of wine being made. The sooner in the process that the stems are removed, the less tannic the wine will be.  When processing white wine grapes, there are two options; either crush and destem them first or just add them straight into the press.  In red wine production, the process of destemming and crushing is usually more forceful than in white wine production. This extracts more pigments and tannins from the grape skins and allows the must to macerate.  Sometimes the winemaker will leave some stems in the “must” intentionally if the grapes do not contain enough tannins. But this is not always the best strategy, as it can give the wine undesirable green flavors.

  The winemaker can also simply destem the grapes and avoid breaking as many of the skins as possible. This is called whole berry fermentation.  Modern crushing and destemming machines consist of a large steel or aluminum trough with a screw in the bottom. As the screw turns the grapes are gently squeezed and pulled from the stems at the same time. Out one end pops the stem and out the other is your product. The crusher/destemmer shown in our video below has a rubber edge so that the grapes are as gently as possible.  Crushing grapes too hard and you’ll end up crushing the seeds.  This imparts more tannins and astringency in the finished wine.  This can give a green plant taste to the wine.  As with all aspects from plant to glass, great care must be given.  In one swift motion, the machine breaks the skin of the grape, yanks out the stem and sends it towards fermentation.  That will look something like this (also seen in video).  The juice and lightly crushed grapes go from the crusher/de-stemmer directly into the Press, where all the juice is pressed off and separated from the skins. The juice is then transferred to stainless steel tanks where it settles for a day, allowing the solids to sink to the bottom of the tank.  After racking (transferring the wine to a clean tank and leaving the solids behind), a specially formulated wine makers yeast (some winemakers add, some take advantage of ambient naturally forming yeast) is added to begin fermentation (the conversion of sugar to alcohol).

When fermentation is complete, after about 2 weeks, the wine is racked to a clean tank and the temperature is dropped to approx. 28 degrees F.  This cold stabilization process helps to clarify the wine by encouraging the tartrates (harmless, clear crystals), spent yeast cells and other solids to settle to the bottom of the tank. The wine is racked yet again for clarity.  Generally, white wine are made and stored in neutral stainless steel tanks.  Later the individual winemaker will make decisions as to introducing oak etc. into the process. Red and white wines really part ways early on. Because red wine gets much of its color and structure from contact with the grape skins, winemakers  send the entire fruit into a vat, where the must is left to luxuriate on the skins during fermentation, before it’s pressed off. Remember by contrast, winemakers press white wines before fermentation, often as quickly as they can after the grapes are crushed. That immediately separates juice from skins, resulting in a more delicate and light-colored wine.

  Now with red wine the yeasts takes the helm, converting the sugars in the grapes into alcohol and carbon dioxide. In red wines, the juice and lightly crushed grapes go from the crusher/de-stemmer directly into vats where they rest on their skins to extract color and tannins.  Winemakers at this point make decisions that vary somewhat. Yeast will often be added directly to the vats so that fermentation can take place while the juice is in contact with the grape skins.  During fermentation, the juice should have maximum contact with the skins to ensure full extraction of color and tannins.  As fermentation progresses and the temperature of the mixture rises, CO2 is released and the grape skins float to the surface.  The grape “must”  is mixed several time a day (called “punching down the cap”) to insure full skin contact with the juice.

After fermentation is complete the red grapes are pressed, allowed to settle for 24 hours and then racked to a clean tank.  After cold stabilization and more racking or filtering to clarify, most reds are transferred to oak barrels where they age for several months.

  Once in oak, red wines go through a second (Malolactic) fermentation, during which the sharp, malic acid present in the wine, is converted to a softer, lactic acid. Red wines also benefit from the extra tannins and subtle oak flavors that our barrels impart.  Winemakers use French, American and Eastern European barrels for aging reds. Length of time, origin of barrels, neutral or not and any combination may be used to get just the outcome in the wine the individual winemaker is looking for.

  In many ways crush hasn’t changed  since winemaking began thousands of years ago: Grapes were picked,  crushed in some way, fermented and pressed off to produce a wine.  Likewise the impact this season brings to all involved has changed little from year to year or century to century.  That is part of the uniqueness of this very special beverage.

  Crush is such a special time.  I hope you’ve enjoyed this information and your appreciation of your next glass even more, getting to know this part of the process.


Sonoma’s Wine Country Tours Sommelier