September 05, 2013
If harvest is the first step a grape takes on its life’s journey to your glass, crush is most definitely the second— a big, messy, interesting step that makes a large impact on the character of the wine it will become.
Once the grapes have been harvested, they meet some new friends that help them make the transition to juice. The first helpers we meet in the crush process are rice hulls. They are mixed in with the grapes as a pressing agent to form channels for the juice to work its way out. The second helper is a liquid enzyme that is added as another pressing agent that breaks down the pulp in the grape to let is juice more freely.
After the rice hulls and enzyme are mixed with the grapes, the whole mixture goes into the crusher/de-stem-er which separates the stems from the fruit. The grapes (and friends) then run from the crusher/de-stem-er to the press through a hose. There are two primary types of wine grape presses, a basket press (also called a ratchet press) and a bladder press. A basket press works by squeezing the grapes from the top and bottom, while a bladder press works by squeezing the grapes from the inside outward like a balloon.
Once the grapes are in the press they are allowed to juice on their own, this part of the process is called “free run” and produces premium juice. After the free run is complete, the wine press is turned on to get the rest of the juice. The wine grape press works as a sort of colander, straining the juice.
There is some variance in the process used for red and white wine as the seeds and skins from red grapes are the source of the wine’s color.