No. 392

Mushroom Essence

Essence de Champignons

Put one pound of mushrooms previously washed and cut in four into a saucepan with the juice of half a lemon, salt, and a pint of broth; let boil together for ten minutes; cover the saucepan hermetically and let stand till cold; strain through a fine sieve.

← No. 391 Hot Aspic Essence, Clear and Thickened Stocks, Essences & Auxiliaries No. 393 Root Essence →

For the Modern Kitchen

A ten-minute infusion rather than a long reduction: the point is to capture mushroom aroma in liquid form for finishing sauces, not to concentrate it by boiling down.

The hinge: it steeps off the heatThe ten minutes of boiling only starts the extraction. Further extraction happens while the covered pan cools, so do not skip that stage or strain it hot.
"Hermetically" in a 19th-century kitchenIt means nothing more than a tight-fitting lid, weighted or sealed with a fold of parchment if the fit is loose. The aim is to keep volatile mushroom aromatics from escaping as steam.
MeasuresA pint here is 16 fl oz (2 cups); one pound of mushrooms is roughly 6 cups of quarters. Half a lemon yields about 1 tablespoon of juice.
BrothA light white stock, veal or chicken, is the likely intent. The recipe adds salt of its own, so keep the stock itself unsalted or homemade if the essence will be reduced further.
Which mushroomsCultivated white or cremini are probably the nearest match to what a New York kitchen of the 1890s would have bought. Cremini and a handful of dried porcini soaked in the broth give more depth; avoid dark-fleshed varieties that will muddy the colour.
Why the lemonThe acid helps keep the mushrooms and the liquid pale, which matters if the essence goes into white sauces where browning would show; it also brightens the flavour.
Cooling and keepingModern practice is to cool the pan quickly in a water bath rather than let it sit out for hours, then refrigerate. The strained essence keeps 3-4 days chilled and freezes well in ice-cube trays.
Yield and useExpect about 1 1/2 cups after straining. A tablespoon or two finishes a velouté, a cream sauce, or a poaching liquid for chicken or sole.
Don't throw out the mushroomsThe strained solids are cooked, seasoned and still perfectly good in a duxelles, a stuffing or an omelette.

A Little History

The Epicurean (1894) is Charles Ranhofer's record of thirty-odd years as chef at Delmonico's, and it is organised the way a professional brigade actually worked: a long opening section of stocks, essences and "auxiliaries" that the rest of the book then draws on by number. An essence in this system is a flavoured liquid held in reserve, sitting between a stock and a glaze; the mushroom one appears alongside a root essence and various aspics because all of them exist to be spooned into something else at the last moment. The technique reflects a kitchen without commercial flavour extracts, so aroma had to be captured fresh. Cultivated mushrooms are often said to have been a relatively expensive, largely French-influenced ingredient in American cooking of the period, grown in caves and cellars, which may be part of why a pound of them was worth treating this carefully rather than simply cooking into a dish.