The Grapes are Harvested! But How Do They Become Wine?

Vineyards have been busy the last couple of months with harvest.  Once the grapes have been determined to be at just the right ripeness, it's a big rush to get them off the vines and out of the vineyard. And then the magic begins. Turning bunches of grapes into fine wines.  But, how does that happen?

It starts as soon as the grapes reach the winery where the grapes may be de-stemmed or left in whole bunches, depending on the grapes being used and the winemaker's desired outcome. In either case, the grapes are sorted to eliminate any that don't meet the winemaker's standards and to remove any leaves or other foreign matter that might be mixed in with the grapes.  

Now, the biggest difference is that white wine grapes are immediately pressed and the juice is separated from the grape skins and seeds.  But with red wines, the whole grapes or clusters are kept intact. The contact of the juice with the dark skins is what gives a red wine its color. Otherwise red wines would come out nearly clear. And when producing rosé, the dark grape skins are only left in contact with the juice for a brief period of time (hours) in order to just give it a pink hue.

Then it's on to fermentation. Large tanks are used in this process and here is where yeast is added.  It's the natural sugar in the juice of the grape that gets consumed by the live yeast. The bi-product of the yeast's consumption of sugar is alcohol and carbon dioxide (CO2).  Remember that red wines have the juice and skins together in the fermentation tank and the production of CO2 causes all the skins to float to the top of the tank.  So winemaker's have to periodically 'punch down' the skins to intermix them with the juice or 'pump over' the juice as another means of keeping the skins mixed in with the juice. But regardless of the grape type, the fermentation process is relative quick, lasting typically from ten days to two weeks.

Once fermentation is complete, white wines will be moved to stainless steel tanks or oak barrels for aging.  It's at this point that the red wine juice is now separated from the skins and moved to vessels for aging. Typically, red wines are aged in oak barrels, but steel tanks and concrete tanks may also be used.  White wines may be aged for months where reds may be aged for years. The aging times will vary considerably, again depending on the winemaker's preference.

Many oaked white wines and red wines will then undergo another process called malolactic conversion.  This converts the sharp and tart tasting malic acid to softer, smoother lactic acid.

At this point the wines may go through a process called 'racking' where the wine is periodically siphoned or gravity-feed to another vessel to separate the wine from any remaining sediment that has settled in the vessel.  The reds may also undergo a 'fining' process to remove sediment and particles using a binding medium such as egg whites.  Once these processes are complete, the wine is bottled, getting a cork (or twist-off cap), a foil capsule and a label, and then the bottles are boxed into cases and are ready to ship.

And it's just that easy!  But as has been said many times, making wine is easy -- making good wine is hard.  And so, while this process sound relatively simple, it's the great winemaker's, and their attention to details, that makes great wines.

Next time well talk about how the winemaker gets all those amazing flavors into wine. Cheers!