Ahh, the pub beer festival. Don't you love them? Lots of beer - warm, flat and no sign of a sparkler. Seriously, if we don't take any special steps for proper cooling the beer is going to end up at least as warm as the mean air temperature. Sure, people put up a tent or awning to keep the sun off the casks, but the 24 hour average temperature in London (which is where this snap was taken) was probably at least 14°C. Worse than that, there's bound to be a certain amount of temperature cycling - a little warmer in the day, cooler at night. So your beer's probably going to be at the right temperature at about 10 in the morning on day 1, but it'll be flat after being vented too warm the day before. By the evening, and for sure on day 2, it'll be too warm and flat. Yum.
Of course, if you know what you're doing and time everything just right, and you're lucky with the weather, you're probably able to get at least one session where the beer is in good nick without spending money on special cooling.
While we're on the subject - I've never done the experiments, but I'm not convinced of the effectiveness of the old damp bar towel trick, particularly on plastic (or wooden) casks. It looks more like a magical operation to me.
What do you think - is cooling important at all in the BF setting? Or is it just the kind of minor detail that only a saddo like me would care about?
I should say: I'm not commenting on the arrangements at any particular boozer here - the photo is illustrative of what a lot of places do if they're putting on one of these events, and I'm certainly not trying to blame the outlets for any short-comings in the product.
This is Jon's personal "blog" - I work at an independent microbrewery (a small-scale, artisanal producer of “real ale” and other beery treats), based in the Furness area in Cumbria (or N. Lancs if you'd rather). Or a "Craft Brewer", if you like. We're known as "Stringers", or "Stringers Beer". I don't just make beer - I also sound-off in half-informed rants on a variety of subjects. Like here.