No. 833

Green Walnuts

Cerneaux

When the juice is in the almond state, break them in two, detach the white parts with a circular movement, then throw them into cold water in which a little powdered alum has been dissolved; drain through a colander, and throw over a handful of white salt, two finely cut up shallots, and put them into a salad bowl, adding the juice of two lemons; roll them in their seasoning, and serve on side dishes.

← No. 832 Turbot or Red Snapper Marinated Cold Side Dishes No. 834 Pickled Green Walnuts →

For the Modern Kitchen

Ranhofer's cerneaux are the raw kernels of green walnuts, taken while the shell is still soft, dressed with salt, shallot and lemon and passed as a cold relish. The whole dish depends on catching the nut at the right week.

"When the juice is in the almond state"This is the hinge. The walnut must be picked while the shell is still soft enough to cut with a knife and the kernel has set from jelly into firm, milky flesh — broadly midsummer in the northern hemisphere, anywhere from late June into August depending on variety, region and season. Picked too early there is nothing to extract; too late and the shell hardens and the kernel turns bitter and tannic.
How to open them"Break them in two" most likely means halving the whole green fruit, husk and all, with a stout knife, then lifting each kernel half out with a spoon turned against the inside of the shell — presumably the "circular movement".
Green walnuts stainThe husks contain juglone, which turns hands, boards and cloth a deep brown-black within minutes and will not wash off; on skin it wears away over a week or two, on wood and fabric it is effectively permanent. Wear gloves and work on a surface you do not care about.
The alum waterPowdered alum (potassium aluminium sulfate) was a standard nineteenth-century firming agent and is still sold for pickling; a teaspoon to a quart of cold water is a proportion commonly given. It is there to keep the kernels crisp and pale, and it can simply be left out in favour of plain ice water if you would rather not use it — the kernels will be slightly softer.
Salt and shallot"A handful of white salt" is a seasoning gesture, not a cure. Start with about a teaspoon per cup of kernels, toss, taste, and add more; salt also blunts the perception of the remaining bitterness.
Timing and restDress them shortly before service; the recipe has them rolled in their seasoning and sent straight out. Held long in lemon juice they will discolour and soften.
Yield and serviceA dozen green walnuts gives only a modest quantity of kernels — one item among several on a cold hors-d'oeuvre tray. They are meant to be eaten in small quantity alongside other cold dishes, not as a salad in their own right.

A Little History

Cerneaux is the French word for the kernel halves lifted from a walnut, and cerneaux au verjus is a long-standing specialty of Burgundy and the Dauphiné, where the green nuts are dressed with the sour juice of unripe grapes rather than lemon. Charles Ranhofer, chef at Delmonico's, published The Epicurean in 1894 as a complete record of the restaurant's repertoire, and the cold side dishes section is full of these small French relishes served alongside olives, radishes and marinated fish at the start of a meal. Here the dressing is lemon juice. The dish also depended on access to a walnut tree at exactly the right moment, which tells you something about the kitchen gardens and country suppliers a restaurant of that class could still draw on.