I cannot lie, my stomach made a little flip when I walked into the union room at Marston’s brewery in Burton upon Trent on Wednesday. Here it was: the most iconic fermentation system on the planet. The only example left, out of – well, dozens, certainly, perhaps even hundreds, of unions in use in breweries from London to Edinburgh back in the 19th century, though the most famous sets of unions were in the breweries of Burton.
It is not a cheap method of brewing, and accountancy-led brewing companies, combined with brewery closures, means that today Marston’s is the only place where you can still find beer being made in traditional union sets. Pictures don’t prepare for how big the union room is at Marston’s, packed from wall to wall with sets of oak fermenting casks, each double row of 12 casks mounted under a long, deep trough, there to catch the excess yeast produced in the fermentation as it spills out of the swan-neck pipes that rise up from the casks.
This being Wednesday, the unions had just been filled with fermenting beer, which had already spent 48 hours in more conventional fermenting vessels after the initial pitching of yeast into the wort. The regime followed since a man called Peter Walker invented the union system in the 1830s is that after that first fermentation has built up speed, the yeasty wort is “dropped” out of the initial vessels, leaving behind trub and other debris, and run into the troughs above the unions, before descending into the union casks, each one of which hold 162 gallons – four and a half barrels
There, in the dark, the Marston’s union yeast gets into its stride, multiplying furiously as it turns the sugars in the wort into alcohol and carbon dioxide. The yeast loves life in the unions, and it increases so fast it foams up out of the casks and into the troughs in – from some of the unions last Wednesday – a constant creamy pour. The beer the yeast carries with it then runs back into the casks, leaving the yeast behind (to be, eventually, scooped out and turned into Marmite). Fermentation is effectively finished by the Friday, but the beer sits in the unions until the Monday, when it is run off to be packaged in cask, bottle or keg. Despite the expense, Marston’s brewers firmly believe the union system produced a beer with great stability and considerably enhanced flavours, and it is the only method used to make the brewery’s flagship Pedigree pale ale, as it was the main method of brewing in the many other breweries that once filled the town’s air with the beautiful scent of mashing barley, in the glorious past when Burton sent constant trainloads of IPA out around the world
And now, for the first time, Marston’s unions have been used to make an Imperial stout, the latest in the “Horninglow” series of one-off beers, which is why I was up in Burton, to talk to the head brewer, Pat McGinty, about the new beer, and also to have my first ever look at the Marston’s union room (shameful, I know. Call myself a beer writer?)
It’s not totally unknown to use unions to make porters and stouts, and by coincidence only a few days before my trip to Burton I was reading an article in a brewers’ trade magazine from 1878 by Charles Howard Tripp of the Stogumber brewery, near Taunton, in Somerset about brewing porter in unions. But I’m not aware of anyone making an Imperial stout that way. Equally unusually, Pat McGinty has made this 7.5 per cent abv beer using straight-up Burton well-water, rammed as it is with sulphates, which, conventionally, is seen as terrific for pale beers but not so great for dark ones, where a more London-like brewing liquor, with lots of calcium carbonate in, is regarded as optimal. The reason for not altering the water chemistry, Pat says, is to ensure this stout has a proper “Burton” character, which search for a Burton character is the reason for brewing the stout in the unions, and fermenting it with the standard Marston’s union yeast as used in making Pedigree. (The yeast apparently got on fine with the dark grains and the higher OG of the stout, though the brewers had to spend twice as long as they normally do, 4½ hours, cleaning the unions used for stout brewing, to ensure no contamination of the next batch of Pedigree.)
To make up for the possibly unsuitable mineral profile, Pat has used malted oats in the brew, to help round out the mouthfeel: the other grains are pale ale malt, roasted barley, chocolate malt (Charles Howard Tripp was keen on chocolate malt, which had only just been invented in his time, saying: “chocolate malt [gives] a capital rich and full flavour to the porter in which it is used”) and malted wheat, while the hops are Challenger. The beer, which will, I believe, be exclusive to Waitrose, was only two weeks old when we sampled it, unfiltered and heavy on the roasty flavours, and it still had to be filtered, partially carbonated and sent to the bottling plant, where each bottle will be seeded with the same union yeast the beer was originally fermented with (the union yeast apparently happily drops to the bottom of the bottle). It will then be held on to for 14 days before being sent out for sale in stores, though Pat McGinty suggests keeping the bottles for six to eight months to be “nicely conditioned”.
As well as a look at the union room we were also given the chance to meet Marston’s last remaining cooper, Mark Newton, who spends most of his time maintaining and repairing the union casks. That was fascinating, too, and rather sad: Mark has trained up an apprentice, who now works elsewhere in the brewery, but he is currently the last man in the town doing a job that once was carried out by hundreds. Here’s a little photo-essay.