One month at Chevalier: Pressing and Débourbage
This is an old article originally published in September 2014 on Julien Boulard's old blog
Second day at Domaine de Chevalier. Today I wanted to spend some time working at the press, a wish kindly granted by maître de chai (chief winemaker) Nicolas Gougelet.
Domaine de Chevalier has only two pressing machines, both pneumatic, one with a capacity of 30 hectoliters (3,000 liters), and a smaller one of 22 hl. The presses are filled with the whole-cluster grapes brought in 30 kg cagettes, or plastic baskets, with 70 of those needed to fill the big press and 45 to fill the small one. The whole pressing process lasts for approximately three hours, divided in different cycles of different pressure, from 0.15 to 1.9 bars at most. This gentle pressure is one of the main reasons (if not the main) why pneumatic press is favored by so many producers, allowing them to extract a high quality juice. At one point, the juice is separated between free-run juice and press juice. This is decided according to the juice’s pH value. Indeed, the higher the pressure, the more potassium is extracted from the skins, thus the higher the pH becomes. The small press, which is filled with about 1,350 kg of grapes, yields approximately 700 liters of "free-run" juice and 70 liters of "press juice". The first liters of juice are quite dirty, draining out a lot of dust and earth. They are put aside. Then, the juice quickly becomes clearer, and some dry ice (solid form of CO2) is spread on the tray where the juice drips in order to protect it against oxidation. Indeed, as the dry ice melts, it changes directly from its solid form (ice at about -80C) directly to its gaseous form, and CO2 being heavier than oxygen, it creates a protective layer above the fresh juice.
Besides emptying the baskets into the presses, I also learned how to analyse total acidity, pH, potential alcohol and turbidity. I also learned how to clarify the juice the traditional way, known as débourbage à l’esquive. The esquive is the plug which seals the hole at the bottom of the barrel’s side. After pressing, the wine is transferred directly into the barrels which are stored in a cold room (about 4C) over night. The low temperature helps the gross particles in the must (juice) to settle at the bottom of the barrel. The clearish must is then racked off by the hole at the bottom of the barrel, using a hoist towards the end, and poured into another one. Most producers use stainless steel or concrete vats to clarify their wines, and Domaine de Chevalier is one of the few estates to carry on with this traditional method.
Tomorrow’s plan: fermenting white wine aeration and 2013 reds topping-up (ouillage).