Viticulture
The main viticultural concern for Chablis vineyard owners is frost protection. During the crucial bud break period of a grapevine's annual cycle, the Chablis region is prone to experience springtime frost, from March to early May, which can decimate that year's crop. Prior to the mid 20th century, Chablis producers were at the mercy of the vintage as to whether the temperature would stay warm enough during this period to maintain viable yields. The financial risk involve with losing half to an entire year's crop encouraged many producers to practice polyculture agriculture by pulling up vineyard space to plant alternative crops. The 1957 vintage was hit particularly hard by frost damage: the regional authorities reported that only 11 cases (132 bottles) of wine were produced. In the 1960s, technological advances in frost protection introduced preventive measures, such as smudge pots and aspersion irrigation to the region. Smudge pots worked by providing direct heat to the vines while aspersion involved spraying the vines with water as soon as temperatures hit 32 °F (0 °C) and maintaining persistent coverage. The water freezes on the vine, shielding it with a protective layer of ice that functions similar to an igloo in retaining heat within the vine. While cost is a factor in using smudge pots, there is a risk to the aspersion method if the constant sprinkling of water is interrupted which can end up causing even more damage to the vine.
At harvest time, AOC regulations stipulate grapes for Grand Cru vineyard must be picked with a potential alcohol level of at least 11 percent, at least 10.5 percent for Premiers Crus and 9.5 percent for AOC Chablis vineyards. Yields in Grands Crus must be limited to 3.3 tons per acre (45 hectoliters per hectare) with a 20% allowance for increased yields. There is no official regulation on the use of mechanical harvesting, but most Grand Cru producers prefer hand picking because human pickers tend to be more delicate with the grapes and can distinguish better between ripe and unripe bunches. While its use is gradually declining, for the rest of Chablis region mechanical harvesting was used by around 80% of the vineyards at the turn of the 21st century. The traditional style of vine training in Chablis is to have the vine trained low to the ground for warmth with four cordons stretching out sideways from the trunk.
Read more about this topic: Valmur