delestage

Delestage is a winemaking technique used during fermentation, particularly for red wines. The name comes from the French verb "délester," meaning to unload or lighten. In essence, it involves separating the liquid wine from the solid grape skins and seeds that form a cap on the surface of the fermenting must.

The process typically begins after the initial alcoholic fermentation starts. As the yeast consumes sugar and produces carbon dioxide, the solid components are pushed upwards, forming a thick cap. Delestage involves draining the free-run wine from the bottom of the fermentation vessel, leaving the cap behind. Then, the cap is broken up or gently stirred, and the drained wine is pumped back over the solids, effectively immersing and mixing the cap with the liquid. This action is repeated several times during fermentation.

The purpose of delestage is to achieve efficient extraction of color, tannins, and flavor compounds from the grape skins. By repeatedly mixing the cap with the wine, a greater surface area of the solids is exposed to the fermenting liquid. This can lead to a richer, more intensely colored, and potentially more tannic wine compared to other maceration techniques like pumping over. It also helps to regulate the fermentation temperature, as the submerged cap releases heat into the wine. The technique is labor-intensive and requires careful monitoring to avoid excessive oxidation or extraction of harsh tannins.