Pressing Whites, Slowly

There is a commonplace in Meursault that the white wine is made in the press house and the cellar only looks after it. Like most commonplaces it overstates the case, and like the best of them it is pointing at something true: pressing is the one stage where a mistake cannot be corrected afterwards.

Chardonnay for white Burgundy is loaded into the press as whole clusters, stems and all, and squeezed over two or three hours at slowly rising pressure. The stems and intact berries act as a filter bed, creating channels that let juice run out under gentle pressure. Gentleness is the whole point. Anything that tears skins releases phenolic compounds that taste bitter and broad in a white wine, and no amount of skilful barrel work removes them later. They are in the wine for good.

The single piece of equipment most responsible for the quality of modern white Burgundy is not a barrel or a vat but the pneumatic press, which inflates a bladder against the fruit rather than crushing it between plates or under a screw. Older basket and screw presses applied force unevenly and were hard to run gently at the end of a cycle, which is exactly when gentleness matters most. A bladder press applies even, low, programmable pressure and stops precisely. It is an unglamorous machine and a better explanation for the improvement in village-level white Burgundy since 1990 than most of the things usually credited.

Pressing by stage allows press cuts: the juice is separated by pressure, and the hardest last fractions are kept out of the top wine. Early free-run juice is the finest; the final pressings carry phenolics, bitterness and often a hard edge that never integrates. Keeping them apart lets a grower declassify or sell the hard fractions rather than diluting the whole lot with them. It is an invisible decision that makes a large difference, and it is one of several reasons the same vineyard produces very different wine in two cellars.

Next comes débourbage, letting the pressed juice settle so the heaviest solids drop out before fermentation. It sounds like a cleaning operation and is really a balancing act. Juice that is too clean ferments sluggishly and tends to produce reductive aromas, because the yeast needs some of what is in suspension to work properly. Juice that is too dirty gives coarse, bitter wine. Most cellars settle overnight in a cool tank and take the cut by eye, which is a good illustration of how much of white winemaking is judgement rather than measurement.

This is also, uncomfortably, where the premature oxidation story may begin. When white Burgundies from the mid-1990s onwards began browning and drying out at seven or eight years old instead of twenty, every stage of the process was examined, and one theory holds that gentler pressing and cleaner juice left the wines with too little natural antioxidant material to protect them. It is not proven, and other explanations (cork quality, lower sulphur at bottling, more bâtonnage) have their advocates.

Whether or not that theory survives, it carries a lesson worth keeping. Every change described above was regarded at the time as an unambiguous improvement, and each of them was adopted for good reasons by people who knew what they were doing. A change everybody agrees is better can still have a twenty-year tail, and by the time the tail arrives the practice is universal and the cause is nearly impossible to isolate.