Jerez de la Frontera, Andalusia
The solera is the aging and blending system that makes sherry unique — a series of barrels (criaderas) stacked in tiers, with the oldest wine at floor level (the solera) and progressively younger wine in the tiers above (first criadera, second criadera, etc.). When wine is drawn for bottling from the solera, it is partially replaced from the first criadera, which is refilled from the second, and so on. The result is a wine that is both perpetually old and perpetually young: the average age of the solera wine increases over time, but it is never completely drawn out — a fraction of the original wine from when the solera was established remains in the system. Sherry bodegas measure the age of a solera, not the vintage, because no wine in the system has a single vintage.
Maximum draw is one-third of the solera per year — drawing more would compromise the stability of the average age and flavour profile. Each criadera tier refreshes the tier below. The biologically-aged styles (fino, manzanilla) depend on the flor yeast that grows on the wine surface — the regular refreshment from younger wine provides nutrients to the flor. Oxidatively-aged styles (oloroso, amontillado) have no flor and develop through slow exposure to oxygen through the porous oak.
The NV character of sherry is a feature, not a defect — the consistency of a house style across decades is only possible through the solera system. When tasting sherry, ask about the number of criaderas and the average age of the solera — this tells you the complexity of the blending system. The oldest active soleras in Jerez date to the 1820s.
Confusing solera age with vintage — these are categorically different concepts. Assuming an older solera produces better wine — older soleras carry more historical complexity, but the current wine quality depends on the current vinification. Misunderstanding flor — the yeast layer on fino and manzanilla is alive and must be maintained through proper management.
The Food of Spain by Claudia Roden