🍷 Flor wines

Flor wines mature under a film of yeast that grows on the surface of the wine in a cask not filled to the top. EU Delegated Regulation 2019/934 defines development under flor as a biological process in which a film of typical yeasts develops spontaneously on the free surface of the wine after complete alcoholic fermentation and gives it specific analytical and sensory characteristics. The film protects the wine from oxygen and consumes alcohol, glycerol and acids, giving acetaldehyde and a nutty, salty taste.

The same regulation reserves “vino generoso” for dry PDO liqueur wines matured totally or partly under flor for an average of two years in oak, from varieties such as Palomino and Pedro Ximénez: fino and manzanilla from Jerez and Sanlúcar de Barrameda, and the wines of Montilla-Moriles. Amontillado first ages under flor and then without it, in contact with air.

In the Jura the same kind of yeast makes vin jaune from Savagnin: an unfortified wine aged for years under the veil without topping up, unlike the fortified fino of Jerez. Its best-known PDO is Château-Chalon, and it is sold in the 62 cl clavelin bottle. Oxidative wines without flor, such as oloroso and rancio, are related but different.

Why it matters to you. Fino and manzanilla are dry even though they are fortified; serve them chilled and finish an open bottle within days. WHO: no safe level of alcohol exists.

Science has named four flor strains: beticus, cheresiensis, montuliensis and rouxii, identified in the 1970s and mostly distinct strains of Saccharomyces cerevisiae. The veil is picky about place: it behaves differently in Jerez, El Puerto de Santa María and Sanlúcar, and even between two casks a few metres apart in the same bodega. It feeds on oxygen, sugar, alcohol and glycerol, so the wine becomes lighter, while acetaldehyde can climb to ten times its level in still wines.