STEVE G wrote: ↑
Sun Sep 30, 2018 10:26 pm
buksida wrote: ↑
Sun Sep 30, 2018 11:36 am
Chemical or not, Thai beer gives you a hangover unlike anything you'd get in the west so there must be some nasty shit in it. Additionally it is stored in boxes in the tropical heat for months so what stops it 'going off' if not chemical preservatives?
Alcohol is what stops it going 'off', that's why Chang used to be 6.4% and there are plenty of strong beers on the Continent that will give you hangovers to compare with Thai beers, I've drank most of them over the years and suffered accordingly!
Yes, beer doesn't really "go off". It does degrade though and in different ways. Higher alcohol beers will keep better for longer and can even improve with age. Imperial stouts and vintage beers - Fullers Vintage is a good example. Fullers recommend cellaring it for up to 10 years.
Beer usually degrades with age with the hops dropping off first. Of course, the hoppier the beer is the more it will degrade. Very hoppy American IPA's and Imperial IPA's are noticeably less enjoyable when they get older. Anything after 3 months after canning/bottling.
Beer can also be infected with bacteria and this can happen at different stages of the brewing process as well as canning/bottling and even on a draught system. Again the beer won't be "off" but could produce a number of distinct off flavours or could be sour.
Beer can also oxidise, caused by he oxidation of unsaturated fatty acids during malting and brewing. This will produce papery/wet cardboard flavours.
Skunking is another problem and probably the most common. It's caused by beer being light-struck. Some compounds in certain hops are photo-sensitive and will oxidise when light-struck. This produces the compound 3-methyl-2-butene-1-thiol (MBT). MBT is a very powerful flavour compound and produces the flavour associated with that of the malodorous spray skunks produce when defending themselves.
Anyone who's ever drunk a bottle of corona will have consumed a skunked beer. Beer in clear bottles will be skunked in about 3hrs in direct sunlight (green bottles about 3 days). This is the reason lime is dropped into corona as it neutralises the flavour - although it doesn't cure the problem. It's almost impossible to find a bottle of corona that isn't skunked.