What is noble rot in wine?

Noble rot occurs when the fungus Botrytis cinerea slowly infects ripe grapes during humid nights and foggy mornings, followed by dry days.

The fungus makes tiny openings in the skin. During the day the moisture evaporates through them, so the grape shrinks and the sugar content in what remains rises sharply. Research in the trade journal Plant Physiology shows that the dehydration in the final phase of the infection results from small cracks in the wax layers of the skin.

The weather must therefore work in two directions: humid enough for the mould, dry enough to let the grape dry out instead of rotting away.

Grey rot is the same fungus under the wrong conditions: persistent rain and high humidity, in which the grape is broken down quickly and aggressively.

With noble rot the infection proceeds slowly and the grape stays intact enough to dry out. With grey rot the flesh splits open, other moulds and bacteria come along and the juice becomes unusable for good wine.

So the difference is not in the mould itself, but in the weather and in the speed at which the infection spreads.

Sauternes, Barsac, Monbazillac and Coteaux du Layon in France, Tokaji from Hungary and the German Beerenauslese and Trockenbeerenauslese come from noble-rot grapes.

The cahier des charges of the AOC Sauternes prescribes that the wine comes from overripe harvested grapes with the presence of pourriture noble, the French name for noble rot. Permitted varieties are sémillon, sauvignon, sauvignon gris and muscadelle.

The Deutsches Weininstitut describes Beerenauslese as wine from overripe berries affected by noble rot, and Trockenbeerenauslese as wine from berries affected by noble rot and dried to a raisin-like state.

Not all grapes dry out at the same time, so picking is done by hand in successive rounds over the same rows.

The AOC Sauternes lays down that method as harvest par tries successives. In addition, the yield is low: the cahier des charges sets the limit at 25 hectolitres per hectare. The must has to contain at least 221 grams of sugar per litre and the wine has to reach a natural alcohol content of at least 15 percent.

Few grapes, many picking rounds and a harvest that runs well into autumn: together, that explains the effort behind such a bottle.

Beerenauslese is a German Prädikat for wine made from overripe, noble-rot berries that are picked separately from the rest.

The series runs from Kabinett and Spätlese via Auslese to Beerenauslese, Eiswein and Trockenbeerenauslese. The Deutsches Weininstitut gives a must weight of 83 to 100 degrees Oechsle for Auslese. The minimum requirements differ per grape variety and per wine region, and Germany has thirteen of them.

A Trockenbeerenauslese stands at the top of that series and comes from berries dried to raisins.

In the wine & spirits shop at Brink 2 in Bathmen, the dessert wines are together in one place, so you can set French, German, Italian and Hungarian bottles side by side.

Wilt u weten welke fles bij welk gerecht of welk moment past, vraag het dan aan de toonbank of bel 0570 541 278. Wij verkopen geen alcohol aan mensen onder de 18 jaar: NIX18.