Harvest and picking decisions

Several kinds of ripeness mature at different rates, and they rarely peak together. Sugar rises steadily; acidity falls; tannins soften and lose greenness; aroma compounds develop and then degrade.

Picking early gives higher acidity, lower alcohol and more herbal character. Picking late gives riper fruit, higher alcohol, softer acidity and more polished tannin. There is no correct answer, only a stylistic one.

Hand harvesting allows selection and keeps bunches intact; machine harvesting is far faster and can pick at night when it is cool. Machine picking is not automatically inferior, though it cannot pick selectively.

For botrytised wine, picking happens in repeated passes over weeks, taking only the affected berries.

The harvest date is the single most consequential decision of the growing year, because it fixes several things simultaneously that cannot afterwards be separated.

Sugar rises through ripening and acidity falls, and the two move in opposite directions at different rates. Picking early gives lower alcohol and higher acidity; picking late gives the reverse. There is no way to have both.

Sugar ripeness and phenolic ripeness are also distinct. Tannins and colour compounds mature on their own schedule, and in a hot year sugar can reach the target while the tannins remain green — which is the specific problem behind a great deal of over-alcoholic, hard-tasting wine.

Hand harvesting allows selection at the vine and keeps bunches intact, which matters for whole-bunch pressing and for sparkling base wine. Machine harvesting is far faster and can pick at night when the fruit is cold, which is a genuine quality advantage in hot regions.

Warming has moved harvest dates earlier across Europe by two to three weeks over the last half century, and it has widened the gap between sugar ripeness and phenolic ripeness. Picking decisions have become harder rather than easier as a result.