One of the first wine facts I ever learnt about sherry is that it is always non-vintage - a blend of years in a single barrel known as the solera system.
Each year, a little of the wine is bottled and the barrel topped up with younger wine to refresh the blend.
However, sherry has not always been a made in this way - it was originally a vintage wine like any other until, in the 1820s, in response to demands from British importers for greater consistency, sherry makers began blending their wines across barrels and across years.
Nearly two centuries later and the re-emergence of sherry has allowed Gonzalez Byass to release a limited edition set of six vintage sherries from 1994 to 1967.
Like port or Madeira, sherry is a wine defined by its production method - a standardised process does not leave much room for individuality or Romance, and whilst greater consistency may appeal to those with only limited interest or budget, the true afficionado seeks out the rare and superior.
I got to try these dark sherries - four palo cortados, an oloroso and a sweetened amoroso - with winemaker Antonio Flores, Martin Skelton of Gonzalez Byass and Victoria Gonzalez-Gordon at The Connaught Hotel where they are available by the glass.
They are also available to buy in full-sized bottles from Selfridges - prices range from £115 to £240 or £999 for the full set. Only thirty bottles of each have been released.
This, however, is just the tip of the iceberg as there are around 3,000 barrels of older wines potentially available for release.
All the wines showed balance, freshness, elegance and concentration - and were superb.
1989 Oloroso mahogany, fragrant orange blossom; oilier, plumper texture, bitter roasted spices. Long, complex and substantial.
1982 Palo Cortado less fruit, more oxidative and woody aromas, sweet vanilla, tobacco and orange peel. Harmonious, concentrated and long with a firm persistence.
1978 Palo Cortado aromatic with sweet vanilla, aged wood and acetone, bitter roasted spices, concentration and density. Direct and goes on forever.
1975 Palo Cortado rancio, mellow cedar wood, oak and sweet vanilla, soft smooth texture with savoury bitterness developing; finish soft but with some firm persistence. Perhaps at the very edge of its life as an enjoyable wine and starting to become a curiosity.
1967 Amoroso a blend of 85% Palo Cortado with 10% Moscatel and 5% PX; blended in December 2013; darker, almost treacle black, acetone and cedar wood; intensely syrupy sweetness cut through with fresh acidity. Figgy treacle and prunes with sweet vanilla and solid underpinnings. Soft and balanced.
Followed by a light lunch.
Tio Pepe Fino 2013
Tio Pepe Fino 2011
Gonzalez Byass - website
The Connaught - website
Selfridges - website