I only give one wine 100 points in my annual Wine Companion and it is always the new vintage of the wine in question: the Seppeltsfield 100 Year Old Para Vintage Tawny. It is unique in the true sense of the word, for no other winery in the world can release a wine every year that is 100 years old. It was created – if that is the right term – in 1878 by Benno Seppelt to celebrate the opening of a new port cellar for the fast-expanding company he ran. He chose two hogsheads (500 litres each) and stipulated that the wine couldn't be sold until 1978, and so on for every ensuing vintage. Improbably his heirs followed his wishes, making the wine each year, but not selling it until its due time. Nor did the corporate owners who followed – partly due to the fact that the National Trust classified winery and its many associated buildings were of greater concern, and partly due to the fierce commitment of former winemaker/custodian James Godfrey to the 100 Year Old (and its innumerable vinous children). Godfrey was the first to track the chemical changes that occur as the wine ages. Its blend of grenache, mourvedre and shiraz is partially fermented before the fortifying spirit is added, taking the alcohol to 17%. During the next 100 years, the changes take place at different rates. Alcohol increases rapidly from 17% to 24% over the first 20 years. The baume (sugar) doubles to 12.5 over the first 60 years, then to 14 baume over the final 40 years, and acidity increases from 4 g/l to 9.5 g/l during the first 40 years. The most visible changes are from a deep purple-red in its first few years, to dark mahogany with an olive-green rim at 100 years.
Source: James Halliday.