There's a fascinating piece in the NYT today about how beer and geology are intimately intertwined -- and not just by the fact that geologists like to kick back with a cold one after a day of rockhounding. Because beer is 90% water, the mineral profile of the water makes a huge difference to the taste. The geology has a profound effect on the water, for example:
Burton-on-Trent sits on sandstone rich in minerals like gypsum from water that had percolated through the rocks long ago. The waters had a pH of 5 to 5.5, ideal for extracting sugars from malted barley steeped in warm water, an important step known as mashing."This is why the Burton waters were so good for brewing," Dr. Maltman said. "It turned out they had a very high mineral content, but just in the right balance to get the right acidity for good leeching, good mashing. The balance of fermentable sugars has everything to do with the flavors and the kind of beer that results. The mashing stage is crucial." ...
Pilsen, in what is now the Czech Republic, became a noted practitioneer of lagers, and geology again had a central role in defining the taste. The well water of Pilsen is drawn from a formation of metamorphic rocks, transformed underground by high pressure and heat so that they are almost impermeable. The water slides through cracks, but it draws almost no minerals from the rocks. This mineral-light water enhanced the clean, light taste of the beer, which became known as Pilsener.
Burton-on-Trent had a fortunate local happenstance that helped make its beers great, but it also benefited from a global change that took off during India Pale Ale's nascent years. Before the late 18th century, malt had to be roasted on wood fires, which made it dark and pungent. The Industrial Revolution brought coke-fired furnaces, which burned cleaner, resulting in a cleaner, paler malt than wood fires could manage.
The India Pale Ales that Burton made famous depended on this pale malt, which luckily went well with the high-sulfate water they had at their disposal. The high sulfate content also made it easier to use large quantities of hops (because sulfate buffers the perception of bitterness, which otherwise would be intolerably harsh in a highly-hopped beer). With the preservative effects of massive quantities of hops, the early IPAs were perfectly set up to survive the long trip to India.
As always, it seems, modern life has no use for local variations. Faced with seasonal and regional variations, brewers attempt to surmount them:
Technology has allowed brewers to overcome the traditional limits of geology, and brewers know how to compensate for year-to-year variations in barley and hops to produce a consistent taste.
A "consistent taste" is the hallmark of the modern industrial megabrewers (Anheuser-Busch, Miller, Coors, etc). But the very processes and ingredients they use to achieve that consistency result in a muted, lifeless beer. The idiosyncrasies and delights of a living beer are destroyed by pasteurization and filtering, which remove all the yeast, making the beer a stable, static product.
Craft brewers, for the most part, abhor this: they want to keep the beer alive, the better to savor the local and temporal oddities that make each beer different from the next. In this way the craft beer market preserves a little slice of an ancient method of production from the inexorable "improvements" offered by modern society.