Icing on the Cake, Pt. 2
Welcome back imbiblious masses,
Last week, we discussed some of the science between that flock of bubbles atop our beers, the foam layer we call the “head,” and this week we’ll shift our attention to the second part of the equation, namely how cultures around the world feel about this wispy tricorn, and how those feelings have brought about some absurd-looking pints and even more incredulous legal dispute.
How Much of the Beer Should Be Head?
You might expect an answer that’s north of 0% and south of 100%, so maybe 5%-30%, and anecdotally you’d be pretty much right, but in terms of describing the range of actual possibilities and strong opinions, you’d be dead wrong.
On one extreme, you have this insanely cool but just...super weird Czech mutant called the “Milk Pour,” or mlíko (milk). What? Why? I have no good answer for you, but the fact that Hefeweizens are apparently a popular choice for this treatment makes some sense - they’re already effervescent styles with bold aromas and a silky, fuzzy mouthfeel, so a pint full of foam doesn’t sound all that far from a pint of Hefeweizen, or at least the jump is across a smaller gap.
As for the other extreme, in doing the research for these posts, I re-discovered that the British are absolute freaks when it comes to their beer. I’d read anecdotes about their distaste for large heads, but then I stumbled upon this wild article, in which consumer minister Melanie Johnson got absolutely roasted for her proposal that beer should contain 95% beer (for reference, our draft beers contain closer to 90%), because those madcaps at CAMRA argued that it should be 100%, since any foam should sit fully atop the beer. Freaks.
In between them is the rest of the world, but there is one interesting pseudo-100% team worth mentioning - the fine folks at my (second?) favorite US brewery, Bierstadt. In this NYT article, they make the case that, since their glasses have volume markings (a half-liter marking being pretty common practice for German beer), the foam is essentially free beer above what amounts to a 100% beer pour. Now that’s a sane argument for an “all-beer” pour.
Speaking of Bierstadt, while the quantity of foam is one source of variation, its texture is just as important.
What’s in a Head?
If you’ve watched us pour cask beers for long enough, you may have noticed that occasionally, the swan necks have these short, white, plastic “sparklers” attached to the end of them, which tends to result in a head consisting of smaller bubbles, and perhaps more closely resembling the head of a draft beer than a standard cask pour. While we often do this for beers that are a touch low on carbonation, the practice is actually a regional one, specific to the Northern regions of Britain.
The gist is that the small holes in a sparkler (since they’re akin to tiny shower heads) force the beer through at higher speeds (since the surface area of the output is reduced, but the rate at which the volume is being pulled through is constant since it’s tied to the rate at which you pull the beer engine’s handle...it’s a complex mechanism), and thus at lower pressures, the resulting being a larger jump between the pressure of the beer as it was in the cask (in the line, really, but the difference is slight), and the pressure in the sparkler, forcing more CO2 out of solution.
As to why the bubbles are smaller, well, I suspect that has to do with the speed of the jets of beer (so, not the hole size), but I skipped like 80% of the classes for my Fluid Dynamics class, and CSUN hasn’t offered one when I’ve looked, so ask me again in a year.
“So that’s the UK - what about Bierstadt? We demand to hear more about Bierstadt.”
I’ll happily oblige you. They have this insane beer/serving method hybrid called the Slow Pour Pils, and the whole schtick is that they take five minutes to pour the thing, almost all of which is spent babying the head, more or less topping it back up as the foam collapses (and this seems to be as much bubbles shrinking as popping). Well, they’re not doing it out of spite - it turns out that there are a number of games they’re playing here, namely: letting the temperature of the beer rise somewhat, from the frigid 38˚F of most US draft systems to a balmy 45˚; driving off some of the carbonation in the beer, in order to soften the bite of the carbonation and, so says Queen Ashley, to actually soften the hop bite; and finally, drying out the bubbles themselves by letting gravity pull the beer out of them, contributing, so they say, to structure and stability.
Is this really a big deal? I have no scientific answer for you, but you can’t even buy kegs of Slow Pour Pils for your (Colorado-based) bar without using their custom glasses and agreeing to do this, so apparently the fine folks at Bierstadt think so.
Why Carbonate at All?
This seems like a waste of time, why not just slam back flat beer? True story: my favorite beer, if I’m leveling with you, is room-temp PBR, and the carbonation isn’t too pronounced once you’ve hit the half way mark; it’s very cask-y. I’d actually love a Steam Beer on cask, now that I’m thinking about it.
But I digress; indeed, not everyone carbonates their beer, making this a moot point. Notably, some Belgian lambic brewers will bottle or keg their beers carbonation free, since the sharp tartness of CO2 is totally unnecessary in their already-tart and texturally rich beers. This trend seems to be picking up a (very slight) amount of steam in the US, wherein some craft brewers are starting to experiment with Belgian beers, naturally, but also big stouts, sours generally, and beers aged in spirit and wine barrels. Big, personable beers that don’t need the help, in other words.
And then you’ve got the beers that aren’t quite still, but where carbonation is clearly kind of an afterthought, like Umqumbothi (anything with stuff floating in it will generally have weak carbonation, since those things act as nucleation points; see, for instance, Orangina), and that ancient form of beer for which the straw was invented. Clearly, if you’re not too worried about your lauter “running clear,” or the intensity of your hot break, you’re probably not going to put much effort into carbonating your beer.
Conclusion
There’s no universal answer to whether or not beer should even be carbonated, let alone what to do with the resulting foam if you decide it should be, but the throughline of quality seems to be deliberation and care on behalf of the bartender. If you’d like to experience the rainbow yourself, you can (usually) see sparkled and non-sparkled cask ale heads, nitro pours, and standard American beer pours in person, and if you ask me really nicely when we’re not busy, I’ll pour us a couple of next-level Van Ices or London Lagers
Cheers,
Adrian “Hard Pass on the Milk Pour” Febre