A great wedding-feast is coming and the beer will not work — the hostess of the hall cannot remember the secret that makes it foam. That missing knowledge is what the record files under this address, and its witness is the Kalevala (Finland's oral poetry, compiled 1835–1849), in the rune that sings "the origin of brewing." Louhi, hostess of Pohyola (the Northland), confesses her ignorance without shame: she cannot "comprehend the malting"; "Never have I learned the secret," she says, "Nor the origin of brewing." An old man answers with how it began — how hop-vine, barley, and water agreed to "join our triple forces" — yet the deeper secret is not in the ingredients.

It is in the ferment. "Osmotar, the beer-preparer," boils hops and barley faithfully and still cannot "generate the ferment"; the brew stays "cold and lifeless." Twice her helper, the magic maiden Kalevatar, lifts a splinter and then a chip from the caldron, and the virgin Kapo rubs her hands and knees to make a creature of it — first a squirrel bearing fir-cones, then "a magic marten" sent to the bears' dens for "foam from lips of anger," from "the lips of bears in battle". Neither wakes the brew. Only when a "honey-bee" is made and flown to an island of flowers, and its honey stirred in, does "the wedding-beer" ferment and rise foaming over the vessels — and the poem arrives at the thing it set out to name: "This the origin of brewing".

Our shelf keeps only this one Finnish witness for the secret, though it is a lavish one, spending hundreds of lines on a single act of yeast. There is something exact in the myth's instinct that the mystery of beer lies not in the grain or the water but in the wild, unseen agent that wakes them — where did the old singers suppose that foam came from?