D on’t get me wrong: I love strong beer. My path to beer writing ran via the likes of Rochefort 10 with its 11.2% alcohol by volume and various Imperial stouts. But I’ve always maintained an affection for the everyday session cask beers with which my drinking career began, an attachment strengthened by the dawning realisation that, while all alcoholic drinks can deliver on the strong stuff, producing a satisfying, flavourful liquid suitable for drinking in quantity at 5% ABV or below is something only brewers can do well.

‘Session beer’ culture is particularly strong in the British Isles where, thanks to a combination of Temperance-influenced public policy, wartime shortages and the peculiar economics of the domestic brewing industry, average beer strengths from the second half of the 20th century have been around 1% ABV lower than in the rest of the world. Many British drinkers consider any beer above 4.5% as potentially brain-damaging, perhaps because they have trouble with the concept of drinking it in any measure smaller than a pint.

This preference has dovetailed fortuitously with the retention of cask beer as an everyday format. The gentler carbonation levels and slightly warmer serving temperatures cask makes possible promote drinkability, while bringing out the complexity of more delicately-flavoured beers at lower strengths, especially in traditional styles which dial back on the hops so malt and yeast notes can shine.

To me, the ultimate vehicle for showing off the unique advantages of cask beer is a good session-strength mild. Greene King KK, which sadly now belongs better in a Footnote rather than a Flagship February, is the first one I remember really enjoying in the early 1980s and my preferences still tend to the darker and sweeter side. Milds remain my navigation aid at beer festivals.

Yes, I know that ‘mild’ doesn’t mean ‘weak’ and not all examples are dark – I’ve argued enough times with the compilers of beer competition guidelines on that one – but here is not the place to go into the complexities of the style’s history. And for me it’s among those low numbers and darker shades that the brewer really delivers their virtuoso performance, in achieving a full flavour and satisfying mouthfeel with very little alcohol.

Dark amber-brown in colour, with a smooth and sticky head, it has a rich malt aroma reminiscent of the sticky English fruit bread known as malt loaf, with caramel and chocolate hints. These suggestions follow through on the nutty palate, though it’s notably dry without being bitter, which only makes it more drinkable. A hint of herbal hops emerges on the finish with a dab of blackcurrant.

It originates from a microbrewery established by Nick Davies and his family in 1993 in the village of Cleobury Mortimer, Shropshire, in the English West Midlands. Back then the UK beer scene was a different place and smaller breweries mainly focused on supplying pubs and festivals with cask beers in traditional styles, but Hobson’s didn’t add a mild to its range until 10 years later.

The style has long been on the endangered list, though the brewery is in one of the regions where it maintains some indigenous popularity, particularly around Birmingham and the Black Country. “We’d always wanted to do one,” Nick tells me. “People round here still go looking for a good mild with a low gravity, something that’s good with a lunch, and we’d always liked darker beers.”

As with many others in its style, it can only be appreciated in cask, in a pub with a good turnover where the staff know how to look after it. The brewery recognises that it’s too delicate to bottle; there is a bottle-conditioned version, Postman’s Knock, but it’s stronger (4.8%) and has added vanilla pods. Besides, enjoying a beer like this in a decent pub is part of the sociable experience of the session beer.

The mild is certainly not Hobson’s biggest seller – it’s made once a week on the smaller (20 hl) of the brewery’s two kits – but it’s become a key part of the brewery’s identity, particularly since it was named overall winner at CAMRA’s Champion Beer of Britain competition in 2007. It has a keen and regular local following boosted by the decline of milds from bigger Midlands breweries like Banks’s.

At Birmingham’s Post Office Vaults, where they offer a fine pint of it as one of the regular beers, the manager tells me that “we mainly sell it to the old boys during the day.” I wonder if that raises an issue for the sustainability of a style that seems so out-of-whack with current fashions. “I don’t think so,” he says. “The people who know their beer appreciate this alongside the hoppy stuff.”

“We’ll never lose the mild,” says Nick. I hope he’s right.