Cordyceps

Cordyceps sinensis begins as a spore infecting a ghost moth caterpillar buried in Tibetan and Himalayan soil above three thousand metres. The fungus consumes the larva over winter and in spring pushes a slender dark club out through the head. Collectors comb the high pastures for it by hand. Wild material reaches extraordinary prices, so the overwhelming majority of what is sold — including ours — is a cultivated strain grown on grain substrate, with no insect involved at all.

Cordyceps is graded on two markers, and a reputable supplier will state both.

Cordycepin is 3'-deoxyadenosine — adenosine with a single oxygen atom removed from the sugar ring. That one absent atom is the whole of its biological interest, since molecules built to receive adenosine will accept cordycepin and then behave differently. The beta-glucans are a separate matter: they sit in chitinous cell walls that cold water cannot open, which is why cordyceps is decocted rather than steeped and why a cold-brew preparation extracts very little of what you paid for.

Recorded in Tibetan and Chinese practice for centuries under the name yartsa gunbu — summer grass, winter worm — and reserved for the wealthy because of what it cost to gather. Traditionally simmered into broths with duck or chicken rather than taken alone.

Summer grass, winter worm.