Hops

Hardly any hops grow around the bay; brewers source them from the Pacific Northwest. The region plants 17,057 hectares of hops and supplies around 40 percent of the world's alpha acid. Alpha acid is the compound in the cones that later brings bitterness to the beer.

Hops shape two completely different beers here. In California Common, they provide a bitterness of 30 to 45 IBU, a scale for the bittering compounds in beer. That's enough to rein in the caramel malt without being overbearing. The aroma is resinous and woody, with a hint of citrus.

With the West Coast IPA, also known as American IPA, it's about more aroma. The range spans 40 to 70 IBU. But the number alone doesn't tell the whole story: what matters is when the cones go into the kettle. Boiled early, they provide bitterness. Added late or dry-hopped, the volatile oils are preserved, and the beer smells of grapefruit and pine.

The varieties used come from American breeding programs. Cascade, released in 1972, became the face of the new craft wave on the West Coast. Centennial, Simcoe, Amarillo, and Citra followed later. They all share aromas of citrus fruit, resin, or tropical fruit.

The fact that the Bay Area gave rise to craft beer is also tied to this variety diversity. Pioneers like Anchor Brewing and New Albion showed in the 1970s that American hops could offer more than bitterness. From the Bay, the idea spread throughout the West.

Anyone who tries a Steam Beer and an IPA side by side can taste the difference instantly. One seeks balance, the other puts hops center stage. Yet both are children of the same region.