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Mushrooms, Powdered
Get large mushrooms, but remove the brown end and the outside skin, and see that they are quite free from grit and dirt. Put them into a stewpan with a couple of onions, each stuck with six cloves, two blades of mace, some white pepper, and salt. Place them by the side of the fire to heat gradually, and draw their juice, then shake the pan over a clear fire until the moisture has dried up; this must be done briskly, or the mushrooms will get burnt and useless. Dry them in a cool oven; they will require to be put in several times, until they can be reduced to a fine powder. Fill quite dry bottles, and keep in a dry place, the bottles to be corked and sealed. Sufficient for a gallon.
A Victorian umami seasoning: mushrooms cooked down with aromatics, dried hard, and ground. The whole thing succeeds or fails on how thoroughly the powder is dried before it goes into the bottle.
- The hinge: bone dry or nothingAny residual moisture will cake the powder and can spoil it in the jar. The mushrooms should snap rather than bend before grinding, and the ground powder should be left uncovered in a warm dry place for an hour and re-checked before sealing.
- "A cool oven"Probably somewhere in the region of 200-250F, with the door propped slightly ajar so moisture escapes; the book gives no figure. The instruction to return them "several times" suits an oven whose heat was falling as the fire died; a low oven or a dehydrator at 135-145F does it in one long session of six to twelve hours.
- Peeling and trimming"Remove the brown end" means the woody base of the stalk. Skinning the caps was standard for field mushrooms with tough or dirty skins; cultivated chestnut mushrooms and portobellos need only a wipe. Do not wash them in water at this stage.
- Blades of maceMace is the lacy aril around a nutmeg seed, sold whole as "blades" or ground. Two blades is very roughly a quarter to a half teaspoon of the ground spice, depending on the size of the blades.
- The aromatics come outThe clove-studded onions and mace flavour the juices as the mushrooms sweat; the original does not say so, but lift them out before the mushrooms go in to dry.
- Drying the pan outOnce the mushrooms have given up their liquid, the pan must be worked over a good heat, stirring constantly. This is the stage the original warns about: the sugars in the concentrated juice scorch fast and a burnt batch tastes of nothing but ash.
- GrindingA spice grinder or clean coffee mill does the job far faster than a mortar. Sieve afterwards and re-grind the coarse fragments.
- "Sufficient for a gallon"Genuinely ambiguous in the original: it most likely indicates the volume of fresh mushrooms the method suits rather than the yield. Expect about 1 oz of finished powder from 1 lb of fresh mushrooms, so a gallon of raw caps gives only a small jar.
- Using itA teaspoon deepens a gravy, stew or soup. Add it early enough to hydrate, and remember it carries salt already, so season the dish at the end.
Mushroom powder and its wetter cousin mushroom ketchup were staples of the English store cupboard from the eighteenth century onward, when the flavour we now call umami had no name but was well understood as the thing that made a plain gravy taste of something. Field mushrooms appeared in glut in late summer and could not be kept, so cooks turned them into concentrates: ketchup for liquid seasoning, powder for dry. Cassell's, compiled for late-Victorian households that still expected to lay in their own preserves and flavourings, files this among the fundamentals of the kitchen rather than as a dish in itself. The clove-and-mace seasoning is characteristic of the period, a survival of the older English habit of perfuming savoury preserves with warm spice. Commercial stock cubes and yeast extracts, which arrived around the turn of the twentieth century, gradually made the practice unnecessary, though the powder outperforms both for pure mushroom flavour.