December 09, 2008
Oxygen vs beer
This week's issue of MauiTime Weekly is about local booze. Jacob Shafer, the editor and author of some of the article (and not coincidentally my brother-in-law, hence the reason I'm reading the MauiTime Weekly at all ...) wrote an interesting sidebar on the bottle vs can debate in which the tide appears to be turning in favour of cans. But in my not-so-humble opinion, the bottle vs can debate still really comes down in favour of cans for cheap beer ...
Oxygen is beer's worst enemy—the more that seeps in, and the more CO2 that seeps out, the greater the likelihood of a skunky product.
Now, that may be true for the modern-brewed lager-type beers which tend to dominate the US market, where the the short brewing time and lack of secondary fermentation leads to a need to "push" carbon dioxide into the beer either during bottling/canning or, in a bar, through the keg to the pump in order to give it the fizz that US consumers enjoy. But for quality European-style ales and traditionally-brewed lagers, residual yeast with added sugar ensures secondary fermentation, and this can only occur in the presence of oxygen, yeast being an aerobic organism. Quality bottled ales and lagers will always have a "sediment" at the bottom, which is not some nasty accident but a small amount of that yeast and sugar I mentioned, added during bottling, to keep the beer carbonated and fresh during storage. This means that good bottled beer may last for years, like a bottled wine, as opposed to canned or bottled filtered beer, which has a shelf life of only a few weeks and, when opened (as long as you cover it, refrigerate it and keep the sediment in the bottle), the yeast will keep the beer drinkable for at least a day or two.
As a side note, English-style cask beer, while often derided for being flat and warm, should be neither if it is properly conditioned. At Charlie's Bar in Copenhagen, my favourite watering-hole and, yes (disclaimer), also my part-time employer, we provide beer served via pumps connected to six nine-(Imperial) gallon casks (firkins) stored in a special "cask fridge". Before they are served, the casks are first put into a cask-conditioning unit to lower the temperature from ambient down to around 12.5C. When this temperature is reached, they are "spiled", meaning a wooden peg is hammered into a wax- or plastic-filled hole in the top of the cask to allow oxygen in and wake the yeast up, allowing the secondary fermentation to continue. When a previous cask is emptied in the cask fridge, the spiled cask is brought across to replace it, a tap is hammered into the front of the cask, and the beer pump is connected to serve those thirsty customers. Note that there is no added carbon dioxide at any stage - it's all done with hand pumps and gravity! It's very labour intensive to look after beer in this way, but the end result is a satisfying, tasty, frothy pint at 12.5C - definitely NOT the flat, warm stuff of English legend!
There's details of the Charlie's Bar (patented) cask system here (in .pdf format) and the Charlie's facebook page is here. At the time of writing, there are two Christmas beers (Batemans "Rosey Nosey" at 4.9% and Cotleigh "Red Nose Reinbeer" at 4.5%) and one Porter (Archers "Black Jack" Porter at 5.5%), along with three "standard" ales (St Austell "Proper Job" at 4.5%, Batemans "XXXB" at 4.8% and Harveys "Armada Ale" at 4.5%).