Processing the Grapes: After a couple days battling bearings and starter capacitors, I had the destemmer ready to go. Wednesday, August 27th, we processed our Brianna grapes. The grape clusters are manually shoveled into the destemmer hopper. This machine spins the berries off of the stems, and simultaneously breaks the berry skin. An internal pump moves this mash of skins, pulp and seeds(now called MUST) thru a hose to the vertical bladder press.
The press squeezes the juice from the must, which we then pump to a tank. Our grapes fall into what is known as “slip-skin” varieties. During processing the skins slide whole off the pulp. These skins can then form nearly impenetrable walls inside the press, preventing the juice from getting out. So we use rice hulls in the press. Rice hulls are the seed coating left after rice is processed, and dumping adequate amounts in the press with the must forms channels that the juice can use to escape. It allows us to increase the juice yield. A typical juice yield from a ton of grapes is 150 gallons. We got a yield of about 168 gallons per ton using the rice hulls.