Reviving Glasgow Porter
Gareth Young is an erstwhile philosopher from the University of Glasgow who homebrewed in the spare time he was not reading or teaching. It led him to open his own brewery, Epochal, about a year ago. Since he’s a bookish fellow, it’s no surprise he was captivated by the vat-aged beers of the 19th century. At Epochal, these are the only beers he makes, and I had reached out to him to talk about stock ale for an article I was writing for Craft Beer and Brewing. His insight there was extremely helpful (stay tuned!), but he added an aside that really intrigued me about Scottish porter-brewing:
I recently released a beer based on James Steel’s book A Selection of the Practical Points of Malting and Brewing, which I believe is the only detailed account of porter brewing in my home city of Glasgow. Porter was once one of Glasgow’s biggest exports and Steel is a top technical brewer and engineer (he invented the Steel’s masher) so the book is amazing to me. The porter he makes is distinctive, so I’m claiming Glasgow Porter is a real thing, stylistically.
Introducing a new style to the canon? Well, I have to hear more about this. I followed up and Gareth gave me a detailed description about this once-robust tradition. Let’s hear what he had to say.
Gareth released the first of his Glasgow porters, The Fixed Stars, last fall. If you’d like to read a longer piece about Scotland’s history with porter and a nice biographical overview of Steel—a real character—he wrote a blog post about it here. In correspondence with me, he offered more nuts-and-bolts info about the style itself. I am going to turn the post over to Gareth here—his email is full and well-written and I don’t see a reason to intervene.
Malt
“One distinctive feature of Steel's approach concerns grist. The classic London porter grist was pale malt, brown malt and black malt. The classic Dublin grist (as practised by Guinness at the time) was just pale malt and black malt. Steel used pale malt, amber malt and black malt.
Gareth Young. Source: Epochal Brewery
“Steel is a man of rather strong opinions and, despite knowing very well that brown malt is used in all the top London breweries, calls it ‘a mere waste of grain.’ Amber malt is his preferred replacement. This gives the beer a softer roasted character. He also advocates using an awful lot of the stuff — nearly 45% in the lower gravity beers and around 30% in the higher gravity beers.
“There is sometimes a bit of confusion about how closely these malts match their modern equivalents. However, by the time Steel is writing, amber malt production is close to modern practice. Steel actually provides temperature graphs whose specifications match those found in Briggs Malting and Brewing Science (1982), which is probably the most modern brewing textbook to discuss specific temperatures for amber malt. It’s true that some residual smoke flavour would carry over in the old processes, though brewers did try to get rid of it, but I think in terms of flavour compounds like Maillard products, the modern malts are close enough to work with the approach. If you were trying to replicate the character, you could sling in a bit of beech or oak smoked malt, since those are the hardwoods he suggests for achieving the final temperature spike after the malt has been dried by (smokeless) coke.
“The effect of using large quantities of amber or brown malt is, to me, to give a depth and smoothness of roasted character. I've become so partial to it that I actually struggle to enjoy a porter or stout that doesn't have a decent amount of amber or brown malt.”
Hops
“Steel’s favourite hops are Goldings from Kent, but he’s also partial to Spalter and often uses Californian hops (Cluster, one presumes). Under the Steel-Coulson partnership, Steel has an ale brewery in Edinburgh where he’ll use fancy Goldings for his pale ales but for porters he usually goes with either Spalter or US hops for bittering. He advocates using reboiled hops, interestingly. If you've used a bunch of hops inefficiently, either from a high gravity brew or a heavily hopped pale ale, simply boiling them again with a lower gravity, lesser hopped beer (a light porter, for instance) is a way of recovering both unused alpha acids and lost wort extract from the hops (which might well be significant if you're reaching high bitterness in very high gravities with 6-7% AA hops). It's hard to guess exactly what we'd be looking at in terms of IBUs but I'd say 40-80 for most beers.”
Gravities
Epochal’s version of a Glasgow porter throws up a pretty foamy head itself.
“The mature beer should also be well-attenuated. It should be at least 75% attenuated by the end of primary fermentation, and should drop much further later. This contrasts with the sweeter beers which were increasingly coming out of Edinburgh at the time. Indeed, Steel thought it was essential to porter that it be dry and highly carbonated and throw up a big foamy head. It needs, he said, a ‘gaseous and refreshing quality.’ He never made stout above 1.090 because he thought you lost this quality. It’s funny that he still regarded 1.090 stouts as refreshing!
“He has a whole section going through the range of gravities, in fact. He says the lowest gravity export porter is usually 1.050, though he brews what he calls a ‘light porter’ at 1.047 for export to the West Indies and Nova Scotia. The more normal gravities are 1.055, 1.060 and 1.065. The levels at which duty ‘drawbacks’ allow brewers to claim back tax on exported beer increase at 5-point intervals, so brewers usually brewed to these numbers. These porters were sent out in casks, mostly. Bottling processes at the time were fairly primitive so stronger gravities were needed to survive them in good condition — he said bottling porter should be brewed to 1.070. The top end, as I said, was a small quantity of stuff at 1.090.”
Conditioning
“There are some other things which distinguish Steel’s approach as well. Vatting, for example, had gone out of fashion in London but was advocated by Steel. His view was that pale ales were fine to age in trade casks because the increased sediment you got from doing it this way didn't negatively affect flavour, and because they benefitted from the lower contact with air.
“Porters, on the other hand, are classically vatted and not sulphured. Vats involve an extra transfer before they reach final pack, and also tend, in virtue of their shape, to allow a bit of oxygen in. So I think the acid profile in porters would lean subtly acetic, albeit in a very tightly controlled way. This sort of oxygen pickup also helped age out the smoke flavour which was picked up to some degree from malting and which they regarded as undesirable.
“He also blended and packaged differently to London brewers. The classic porter blend, when they vatted in London, was 1 part highly aged porter to 2 parts fresh, unaged porter. Steel used almost all aged porter—85 to 90%—blended with just enough fresh, yeast-inoculated wort to carbonate. He also didn’t routinely age the beer for extremely long periods. His light porter was aged for six months with only the stronger imperial stouts aging for the full 18-month period routinely used for the vatted portion of London porter.”
Overall Impression
“Glasgow Porter, as characterised by Steel, should have a lot of amber malt character, and some black malt character. This gives it a nice spectrum of roasty malt flavour from biscuity, toasted rye bread notes all the way up to coffee and chocolate. It should be highly attenuated with a firm but balanced bitterness. It should also be highly carbonated and have great foam. It should be aged and have Brettanomyces character, but this should be restrained and balanced. Some complexity in aromatic acids like acetic is good, especially in stronger, older beers, but the beer shouldn't be sour.
“I've released one such porter myself, The Fixed Stars, based on Steel's suggestions for a 1.047 Light Porter. I've got one at 1.070, which will be called The Primum Mobile, and one at 1.090, called The Empyrean, in wood as well. These will be released late next year, all being well. Though I'm still ironing out my own versions of his techniques, I'm already really happy with the results. It feels like a distinctive and very nice sort of porter.”
Jeff here again. In my piece for CB&B, I make an argument that British stock-ale brewers of the 18th and 19th century understood things about the ingredients and processes we have lost. Those beers were famous for their refinement, and revivalists like Gareth Young have spent time studying folks like Steel to understand why they were so legendary. In the case of Steel’s Glaswegian stout, I suspect the grist is incredibly important not just for the flavor profile of the different roasts, but in the way those malts interact with a long, clean Brettanomcyes ferment. I am very interested in what Gareth’s doing, and perhaps we can arrange to have him send a bottle and do a follow up. Who knows—maybe we could do a podcast as well!