Other breweries have long since torn down their Burton Union systems as needlessly elaborate, expensive relics. Next Friday, Marston's, a giant among independent breweries, will unveil a brand new machine - a bubbling, foaming. What the magic machine does is to breed the unique combination of yeast strains that give an inimitable complexity of fruity dryness to Marston's ales. It comprises a double-deck ironwork gantry. Along the top deck is a metal trough.
Copper tubes rise from the casks and bend like swans' necks over the trough.
As fermentation reaches a peak in the unions, its natural forces send the foaming liquid up the copper swan-necks into the trough above. There, the foam subsides and the liquid is able to escape through ports that lead back into the unions. This circulation continues for three or four days before the beer has exercised sufficiently to go to the brewery's cellars. There it is racked into conventional casks for three or four days' maturation. Then more sugar and yeast are added before it leaves for the pub, where it has a further fermentation in cask before being tapped.