How much colder would you expect the ambient temperature to be in Edinburgh than London? If they fermented 10º F cooler, that seems a reasonable guess. 10º F is about 6º C. The biggest monthly difference is actually 5.5º C.
Here's an easy-to-understand table:
| Average temperature by month (º C) | ||||||||||||
| Jan | Feb | Mar | Apr | May | June | July | Aug | Sept | Oct | Nov | Dec | |
| London | 6.5 | 7 | 9 | 11 | 14 | 17 | 19 | 19.5 | 16.5 | 13.5 | 9.5 | 6.5 |
| Edinburgh | 3.5 | 3.5 | 5 | 6.5 | 9.5 | 12 | 13.5 | 14 | 12 | 8.5 | 6 | 3 |
| difference | -3 | -3.5 | -4 | -4.5 | -4.5 | -5 | -5.5 | -5.5 | -4.5 | -5 | -3.5 | -3.5 |
| Source: | ||||||||||||
| MSN News and Weather | ||||||||||||
But here's something even more intriguing. The difference in temperature between Edinburgh and Burton:
| Average temperature by month (º C) | ||||||||||||
| Jan | Feb | Mar | Apr | May | June | July | Aug | Sept | Oct | Nov | Dec | |
| Burton | 4 | 4.5 | 6.5 | 8 | 11.5 | 14 | 16.5 | 16.5 | 14 | 11.5 | 6.5 | 5 |
| Edinburgh | 3.5 | 3.5 | 5 | 6.5 | 9.5 | 12 | 13.5 | 14 | 12 | 8.5 | 6 | 3 |
| difference | -0.5 | -1 | -1.5 | -1.5 | -2 | -2 | -3 | -2.5 | -2 | -3 | -0.5 | -2 |
| Source: | ||||||||||||
| MSN News and Weather | ||||||||||||
Not a huge difference, is there? So why didn't they ferment cold in Burton?
I looked up these data a while back and from a different source found an even smaller difference between Burton and Edinburgh.So close in fact that it would be difficult to tell the difference.
ReplyDeleteAh, but in the 19th century it was colder in Scotland due to the hated English forcing the Scots to sell their peat to England, who burnt the peat, making it warmer in England and colder in Scotland.
ReplyDeleteWas that peat brown?
ReplyDeleteGood question Ron, and good questions are the key to pushing ahead the frontiers of knowledge.
ReplyDeleteJust knowing that cold seems to favour beer, both stability and flavour, I'd think there is something to the old stories about Scotch beer in this regard. They probably derive (or ultimately) from a time when brewing was artisan and probably seasonal. Speaking of which, I note that 3 degrees separates the monthly averages of Edinburgh and Burton. That doesn't seem small to me, but I don't know whether it can make the difference to a good beer and indifferent especially in primitive times technologically.
Edinburgh too is a Lowlands city, near water. Brewing elsewhere, especially in the Highlands, may have been conducted under colder temperatures on average.
Finally, it is noteworthy that Burton beer is famous too, in fact often bracketed with Scotch ale as the best Britian produced. Maybe colder fermentation and conditioning than occurred further south helped make that reputation for the Trent Valley even though the factor was not identified in old literature for whatever reason.
I don't think we'll ever know for sure since there are so many variables. But I do credit the old stories about Scotch ale being fermented cold with something, there is a core of truth to it I think. However, the factor became much less important with the onset of industrial and methodical brewing, in Scotland as elsewhere.
Gary
I know London is warmer now than in the 19th Century, so maybe the temperature difference was not as great back then, or perhaps Edinburgh was equally colder than today - i will have to try and find historical temperatures online...
ReplyDelete