As mentioned previously, our first shipment of grapes this fall was accompanied by our new 12hl (317 gal) press, affectionately known as the Beast. Well, last week we let her loose. She is more than double the capacity of our old press, and with the ability to be programmed, the operator is now free to press more grapes, rather than buttons. Pressing grapes is actually a complex, multi-step process. It must be done very slowly, building up pressure gradually so that juice extraction is maximized. With each stage of the pressing, there is an interval of relief to allow juice to flow through open channels in the pomace. Without this, the channels would close and much of the juice would be trapped in pockets. Our current process builds up hydraulic pressure in 10 bar increments (one bar equals one atmosphere, or 14.7 psi). We go up to about 90 bar this way. This is actually the pressure of the hydraulic fluid, not that on the pomace, which tops out at around 4.5 bar.
The first step is to bleed juice from the tanks beginning the day before, so that when the door is opened, there is not a gushing flood. The wet pomace is then shoveled out of the tank into half-ton bins that can be moved by pallet jack to the loading dock. The empty press basket is removed from the press by forklift and placed just below the loading dock to be filled. After pressing is complete, the process is reversed: the dry “cake” is removed from the basket and shoveled for a third time into composting bins. The pressed wine is divided into two parts: light press and hard press. Usually, only the light press is aged in oak barrels. If you look in our barrel cellar, most of the wine from each vineyard is marked as “FR” for free run (the wine which freely flows out of the fermenter during the bleed) and “LP” for light press. The hard press is stored in stainless steel kegs and used for a variety of purposes.
Use of the Press Wine
As you might expect, the press wine is rich, dense and as Robert Parker might say, “backward”. It lacks the aromatic complexity of the free run and is fairly harsh and unbalanced all by itself. It is also slightly sweeter than the free run. Some of the sugars locked up in the pulp are released by pressing, and often the press wine will resume alcoholic fermentation until this residual sugar is consumed. The dried pomace has some alcohol left in it as well: this can be distilled into Grappa or the french l’eau de vie de marc most notably. As our wines are aged in oak, they are constantly evolving. Our head winemaker, David Lecomte, monitors each wine assiduously in barrel right up to bottling. Sometimes press wine is added to the free run if he wants to add a bit more depth or structure. Various combinations are tried until his palate is satisfied with the final result. Care must be exercised because adding too much of the press wine could produce harsh tannins and reduce acidity. This is where a winemaker’s talents play a critical role. Only after many years of experience can a winemaker taste a immature barrel sample and know what needs to be done in order to achieve a final result that is worthy.
Check out the gallery below for illustrations of the various steps mentioned above: