Re-Brew, a beer fermented using yeast cultured from a 133-year old bottle unearthed during renovations in the original Carlsberg cellars has been released to mark the 140th anniversary of the Carlsberg Laboratory.
The original lager from which the yeast, Saccharyomyces Carlsbergensis, was extracted was the first to be brewed using a pure yeast culture. 'Lagers before this were made with many yeasts,' Jon Elks, Carlsberg UK's Master Brewer, told Imbibe.
Carlsbergensis was first isolated at the Carlsberg Laboratory in the 1880s by Dr Emil Hansen, using purification techniques developed in his quest for the best yeasts to produce consistently good beer. Recent DNA analysis shows that the rescued yeast is exactly the same strain as one used in a 1947 Carlsberg beer. Since then, breeding programmes and further research have improved the yeast strains in use, but 'This gives more certainty that the re-created yeast was the original one,' said Ekins.
Back in the 19th century, rather than patent the purification process, Ansen not only shared it with the brewing world, but also purified rival breweries' yeasts for free. Thus the 1883 lager is the forefather of all modern beers brewed using a single strain of yeast.
To ensure maximum historical authenticity, the techniques of the day were followed for Re-Brew, using specially propagated and malted barley, handmade bottles made from Lithuanian glass, and water whose salt content has been altered to mimic water drawn from a deep well dug in the locality in 1883.
'The attention to detail has been excellent,' beer journalist and historian Martyn Cornell told Imbibe. 'Carlsberg has gone to every effort to make it as perfect as possible.'
And what of the beer? Elegant rather than dense, at 5.8% abv it's in the style of a Munich dark lager, the style of the day, the dark colour being driven by the specially kilned malts. The flavours of rich toffee are accompanied by some residual sweetness – the yeast of the day was not as efficient as modern ones for converting sugar to alcohol.
Currently on a 17-stop global tour, Re-Brew goes on sale first in the UK on 1 October. 600 70cl bottles will be available, limited to one per person, at St Barts Brewery, West Smithfield, London. All proceeds will go to sponsor a student on the Masters programme at the University of Nottingham's International Centre for Brewing Science.
At present there are no plans to rebrew Re-brew, but we'll keep you posted...
£12.95/70cl, St Barts Brewery, 020 7600 2705