Geology of Thames Basin and Chalk Additions

If you've been reading through my lengthy brewdays on my 1850s London Porter and my Imperial Rye Stout, you'll have noticed that I added chalk to my Lake Michigan brewing water.  There's lots of great resources out there on the chemistry of mineral additions that I don't want to regurgitate, but chalk adds hardness and alkalinity to brewing water that balances out acidic grains and highlights roasty flavors.

Like most beer innovations, this one occurred by geographical accident.  Porter developed in London because thirsty dockwaters wanted beer and intrepid capitalists wanted to brew it for them at an industrial scale.  But if you look at a map of the Thames aquifer, you'll notice a broad "chalk belt" stretching across the middle of southeastern England.

Source: British Geological Survey
This geological formation took shape as chalk settled what was once ocean floor.  Then the formation of the Alps suddenly exposed it to land, giving us southern England in all of its chalk-y goodness.

But what if Paris or Amsterdam had beat London to the agricultural revolution and industrialization?  The first widely distributed beer style would have been something entirely different that reflected the chemistry of local water.  I guess it's like those alternative history books Newt Gingrich likes to write.

There's lots more nerdy stuff that I can't top over at Zythophile if you're interested.

1 comment:

  1. Two comments, first you have the talent, but not the coaches or attitude to win!