Hops

Hops don't grow in the Highlands. The summers are too short and cool for the trellis systems familiar from Kent or the Hallertau. Brewers in the Highlands and Islands therefore source their hops from England and other growing regions.

Fittingly, Scottish beers have traditionally been lightly hopped. According to the BJCP guidelines, the Scottish Heavy style sits at just 10 to 20 IBU, the unit measuring bitterness. For comparison, a German Pilsner reaches 22 to 40. Malt takes center stage here; hops merely keep the sweetness in check.

That brewers in the north once used herbs instead of hops lies at the heart of the heather-beer legend. This is known as gruit on the Continent—the term for herb blends used to season beer before hops took over. What exactly the Picts put into their beer isn't recorded, and Stevenson's ballad deliberately leaves the question open.

Williams Bros has made heather its signature: Fraoch Heather Ale takes its name from the Gaelic word for heather. Alba with pine shoots and the seaweed in Kelpie follow the same path: the brewery seeks seasoning that grows in the landscape rather than arriving from Kent.

Bitterness and aroma are two different things. Bitterness comes from hops boiled for a long time; aroma comes from hops added late in the kettle. Heather, pine shoots, and honey deliver fragrance and sweetness rather than bitterness, which keeps the region's beers mild.