When I drink some US IPAs I joke that they’ve brewed it by throwing a Christmas tree into the fermenting tanks.
You know, because they taste super-piney. But pine trees have actually been used in beer, along with spruce and fir.

It doesn’t look like a beer ingredient but it once was.

trees. Well, at least the tips of these trees, according to the Oxford Companion to Beer.Those green tips tend to be less resiny and even more citrussy than the rest of the tree (except for the bark, presumably, which would taste barky. Or something). They can be boiled with the wort or concentrated into an essence and chucked into the fermenter.

The idea has been around for a few 100 years – Captain James Cook arrived in New Zealand in 1769 with loads of beer made with spruce tips. The OCB doesn’t record whether he then put it in New Zealand’s ice-filled bath-tub and took out a much tastier beer to drink.
In the early United States, spruce beer was a goer as well and, in recent years, it turns up as a novelty from time to time.

What’s the go here?: For those who have just stumbled across this post, I’m going through the Oxford Companion to Beer (OCB) and posting an entry for every letter. Why? Because I have a copy at home but hadn’t really gone through it page by page and I figured this would be an exercise that would force me to do that.