Late Harvest Wine Production

Late harvest winemaking means leaving grapes on the vine to be picked much later than the normal harvest, so that in favorable autumn weather they continue to develop and gain sweetness, and in damp, relatively warm autumn conditions noble rot can develop. Wines of Germany describes vineyards still unharvested after the main harvest has ended: they have not been forgotten by the winemaker but are waiting to become noble sweet wines. WSET defines 'Late Harvest' as a wine made from grapes that have been left on the vine and picked much later, producing wines that are fuller-bodied and more concentrated in style than wines made from grapes harvested at the normal time. Late-harvest wines can be dry, off-dry, medium or sweet.

• Grapes are left on the vine after the main harvest; in favorable autumn weather they keep developing and gain sweetness every day (Wines of Germany)
• Botrytis is a fungus that can grow on ripe grapes and cause noble rot (WSET)
• Germany's Prädikat levels run in ascending order from Kabinett and Spätlese through Auslese, Beerenauslese and Eiswein to Trockenbeerenauslese (Wines of Germany)

WSET describes two stages of extra-ripeness. Early on, grapes develop exaggerated ripe aromas and accumulate a higher level of sugar; after a longer period they start to turn into raisins as their water evaporates, concentrating sugar, acid and flavour, and dried-fruit aromas may start to develop. In favorable autumn weather, grapes left on the vine continue to develop and naturally increase their sweetness every day, and a German Spätlese needs a minimum must weight of 76 to 90 degrees Oechsle, depending on the growing region. Botrytis cinerea, when the grapes are very ripe and it is damp and relatively warm, attacks the grapes and makes the berry skins porous, drying them up like a raisin as the water evaporates; Bordeaux's wine council calls it the aromatic driving force behind Sauternes. Before picking, the standard grape measurements are pH, titratable acidity and Brix (Oregon State University Extension); German must weight is measured in degrees Oechsle, and Wines of Germany lists Brix in the New World among the comparable measurements. WSET notes that if the sugar level in the juice gets very high, yeast will not be able to complete the fermentation.

• Grapes left on the vine start to turn into raisins as their water evaporates, concentrating sugar, acid and flavours (WSET)
• Noble rot makes tiny holes in the grape skin, so water evaporates and the grape's acids, sugars and flavours concentrate (WSET)
• Must from extra-ripe or noble-rot-affected grapes can be so sweet that yeast cannot eat all the sugar before fermentation stops (WSET)

Late-harvest grapes can have such high sugar levels that they are commonly used for sweet wines with pronounced aromas and flavours (WSET). Wines of Germany notes that in noble sweet wines the yeasts do not ferment all of the natural sugar, so such wines generally have very little alcohol and a thicker, almost oily consistency. For Sauternes, Bordeaux's wine council describes young wines with notes of citrus, white flowers and orchard fruit, and with time aromas of spices such as cinnamon and saffron, tropical fruit, hazelnut, and dried and candied fruit. CIVA, the Alsace wine council, describes Sélection de Grains Nobles as dominated by over-ripe notes with aromas of noble rot, honey and candied or cooked fruits. WSET describes Tokaji as combining intense sweetness with vibrant acidity, and Wines of Germany says noble sweet wines can be aged for decades if properly cellared.

• Botrytis cinerea gives Sauternes over 50 different aromas and flavours, according to Bordeaux's wine council
• Tokaji Aszú shows flavours of orange peel, apricots and honey (WSET)
• Noble sweet German wines have a thicker, almost oily consistency and generally very little alcohol (Wines of Germany)

WSET warns that the botrytis fungus can easily destroy grapes; it is beneficial only on ripe grapes, with damp misty mornings that allow it to grow and warm, dry afternoons that stop it destroying the fruit. The Australian Wine Research Institute (AWRI) describes Botrytis cinerea as a weather-driven fungus that also causes botrytis bunch rot and grey mould, promoted by high humidity or prolonged rain with cool or mild temperatures. In Sauternes, Bordeaux's wine council credits a microclimate influenced by the cool waters of the Ciron River, which flow from the Landes into the Garonne: the combination of morning fog and afternoon sunshine creates the conditions for noble rot. Château Climens describes the same pattern as morning mists, from the convergence of the cold Ciron and the warmer Garonne towards the end of summer, followed by the heat of the afternoon sun. In Tokaj, the Tisza and Bodrog rivers meet, and because their waters are slightly different temperatures most autumn mornings bring fog, followed by sunny, breezy afternoons (Decanter). Picking is laborious: Sauternes is handpicked in successive passes (Bordeaux wine council), and a good Aszú picker may pick less than 10kg per day, visiting each vine four or five times (Decanter).

• Noble rot needs ripe grapes, damp misty mornings and warm, dry afternoons (WSET)
• The same fungus causes botrytis bunch rot and grey mould, promoted by high humidity or prolonged rain with cool or mild temperatures (AWRI)
• Harvests are by hand in successive passes through the vineyard (Bordeaux wine council; Decanter on Tokaj)

Sauternes has 140 winegrowers and 27 châteaux ranked in the 1855 classification, and Château d'Yquem is the one Premier Cru Supérieur among them (Bordeaux wine council). Yquem's own account of the 2022 vintage says Botrytis cinerea spread rapidly from the morning of 15 October. Château Climens in Barsac is one of the rare 1855 Premier Crus Classés to be a mono-varietal vineyard, with Semillon on 32 hectares in a single piece around the chateau, and the entire vineyard has been biodynamic since 2010, according to the estate. In Germany, Prädikat levels are defined by minimum must weights that depend on grape variety and region: 76 to 90 degrees Oechsle for Spätlese (wein.plus) and 83 to 100 for Auslese (Wines of Germany), and Wines of Germany notes that Beerenauslese musts of 120 degrees Oechsle or higher reach sugar concentrations of over 300 grams per litre. Trockenbeerenauslese, from shrunken, shriveled noble-rot berries, is the top of the German pyramid (Wines of Germany). In Hungary, since the 2013 change to Tokaj regulations, all Tokaji Aszú must reach at least 120 g/L of residual sugar, equivalent to five Puttonyos, and six Puttonyos at least 150 g/L (Decanter). In Alsace, Sélection de Grains Nobles takes its name from harvested berries infected with noble rot (CIVA).

• Sauternes: 27 châteaux ranked in 1855, with Château d'Yquem the one Premier Cru Supérieur
• Germany: Spätlese 76 to 90 degrees Oechsle and Auslese 83 to 100 degrees Oechsle minimum, varying by region
• Hungary: Tokaji Aszú at least 120 g/L residual sugar (five Puttonyos) and six Puttonyos at least 150 g/L since 2013
• Alsace: Sélection de Grains Nobles, named for harvested berries infected with noble rot (CIVA)

Botrytis brings winemaking problems. The AWRI notes that it produces an oxidative enzyme called laccase which, in the presence of oxygen, can cause oxidative spoilage and rapid browning of must, and that preventing this damage requires techniques that minimise or eliminate exposure to oxygen. Botrytis can oxidise glucose to gluconic acid, can produce glycerol and, together with bacteria, high levels of acetic and lactic acid; its polysaccharides can create clarification problems in juice and filtration problems in wine (AWRI). Where fermentation is arrested by physical procedures to obtain a product containing endogenous sugar, the OIV's International Code of Oenological Practices allows only heat, cold, filtration and centrifugation. WSET adds that filters can remove yeast from the fermentation vessel before fermentation is complete, giving a lower-alcohol wine with residual sugar. At Château Climens, the estate states that vinification is by small batches in French oak barrels renewed by 30 to 40%.

• Laccase from Botrytis can cause oxidative spoilage and rapid browning of must, so exposure to oxygen is minimised (AWRI)
• Botrytis, together with bacteria, can produce high levels of acetic and lactic acid (AWRI)
• Botrytis polysaccharides can cause clarification problems in juice and filtration problems in wine (AWRI)
• Retaining residual sugar by arresting fermentation relies on physical techniques; the OIV permits heat, cold, filtration and centrifugation

Primary sources (Wines of Germany, the Bordeaux wine council, CIVA, WSET, the OIV, the AWRI, Oregon State University Extension, and producers' own sites for their own facts): https://www.winesofgermany.com/our-wine/quality-standards/quality-standard/182/must-weights, https://www.winesofgermany.com/our-wine/wine-tasting/wine-tasting/192/noble-sweet-wines, https://www.winesofgermany.com/our-wine/quality-standards/quality-standard/449/pr%C3%A4dikat-categories, https://www.bordeaux.com/en/designations/graves-sauternes/sauternes/, https://chateau-climens.com/en/an-exceptional-terroir/, https://chateau-climens.com/en/unique-wines/chateau-climens/, https://2023.yquem.fr/en/, https://www.vinsalsace.com/en/gouts-et-couleurs/cepages/moelleux-et-liquoreux/selection-de-grains-nobles/, https://www.wsetglobal.com/media/13022/wset_l2wines_sessionplans_en_may2023_issue2.pdf, https://www.wsetglobal.com/knowledge-centre/blog/2024/tokaji-decoded-the-science-behind-hungary-s-iconic-sweet-wines, https://www.oiv.int/public/medias/7713/en-oiv-code-2021.pdf, https://www.awri.com.au/industry_support/winemaking_resources/climate-wine-production/managing-botrytis/, https://extension.oregonstate.edu/catalog/em-9583-preparing-harvest-grape-chemistry-prefermentation-adjustments, https://www.vinsalsace.com/en/gouts-et-couleurs/cepages/moelleux-et-liquoreux/vendanges-tardives/. Secondary: https://www.decanter.com/learn/advice/tokaji-sweetness-measured-aszu-430218/, https://magazine.wein.plus/faq/wine-appellation/what-does-spaetlese-mean. Last verified 2026-09-28