While visiting the Griffin Brewery yesterday, I learnt that Fullers plans to tap the interest in historical beers by digging through its old recipe books to launch a new line called Past Masters. The first in this series is a 7.5% strong mild (as the brewers apparently describe it) or strong ale (as the marketing chaps prefer to call it) called XX and based on a recipe from 1891 - September 2nd, 1891, to be precise!
The Fullers brewers worked with beer historian Ron Pattinson to identify modern equivalents of the 1891 malts and hops. They also had to find ways to compensate for the differences between 19th and 21st century sparging methods, temperatures and brew lengths. The XX recipe also incorporates sugars at the end, which today's Fullers beers do not.
XX will be available in bottle very soon - it's not on the Fullers website yet but it is already listed on Ratebeer (edit: no it's not - as there were no actual ratings for it, one of the moderators deleted the entry. It's restored now though!), and I'm told it is announced in an issue of the Fullers Fine Ale Club magazine "First Draught" due to reach subscribers this week. It's intended to be bottled-only, but I'm told there may be some "extremely limited edition" cask XX.
They're about to start work on Past Masters no.2, which will "probably be a strong double stout". Each of these beers is likely to be a single batch only - they're something of a labour of love for the brewers.