How Red Wine is Made
Over the last week the focus in the winery has switched over to the red harvest, so we thought we'd take a quick moment to review how red wine is made. Once our red fruit has been hand-harvested and delivered by tractor to the winery the grapes are destemmed and put through the must chiller which brings the berries to a consistent 50 degrees and agitates the berries, bursting them open. These berries, juice skins, seeds and all are pumped into open-top tanks where the magic of fermentation occurs.
When the internal temperature of the tank has reached 80 degrees it is time to inoculate! The grape must (freshly crushed juice, skins, seeds, and stems) is inoculated with the winemaker's desired yeast and begins fermentation. When we talk about fermentation in wine we are referring to the chemical process of yeast cells consuming the naturally occurring sugars in the grape juice, producing alcohol and releasing carbon dioxide and heat. During the ferment as CO2 is released it rises, lifting the skins to the top of the tank.
All of the tanks at the winery are temperature controlled by heating/cooling jackets that are built into the tank. These "jackets" control the internal temperature of the tank which is key during fermentation as yeast likes very specific conditions. Too warm and the yeast will overheat and die, too cold and the yeast will fall dormant and fermentation stops.
We need to ensure that the juice stays in contact with the skins throughout the fermentation process as the skins are what give red wine its color and tannin. As a result, throughout the fermentation process "punch-downs" or "pump-overs" occur regularly. At Suhru we use the punch-down method to ensure our red wines extract all of the desired color, flavor and tannin from the grape skins. Punch-downs are done mechanically by using a large mechanical foot or punch-down device which breaks up the grape skin cap that forms at the surface of the tank and reintroduces the skins into the juice. This process is done three times a day at the beginning of fermentation, gradually slowing down as the rate of fermentation slows and less and less CO2 is released. The time necessary to complete fermentation can take anywhere from 14 days up to a month depending on the healthiness of the yeast and the amount of sugar in the juice.
Once the fermentation process is complete and all of the sugars have been converted to alcohol the grape skins settle to the bottom of the tank and the juice is drained off and pumped into a new tank. In order to ensure we get every last drop of wine from the settled skins, the remaining grape skins are shoveled out of the tank and forklifted over to the press where we extract the remaining wine.
From here the wine is racked into oak barrels where it undergoes secondary fermentation or malolactic fermentation. During this second fermentation process the sharp, astringent malic acid is converted into lactic acid which gives the wine a softer, rounder mouth-feel and more pleasant drinking experience.
Once this process is complete the wine is racked into different barrels where it will stay in our temperature controlled barrel room for the next few months as it ages. Throughout the aging process the wines will be regularly checked and tested to assess a number of key components to ensure the wine is developing as expected.
Before bottling, the red wine is filtered to make sure it is clear and free of any microbial bacteria. The bottles are then aged for three to twelve months, and released once our winemaker deems them ready for consumption.