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Grating

Also called microplaning, freshly grated

Quick answer

Rasping a hard spice or a fresh rhizome to a fine pulp or powder at the moment of use — nutmeg, fresh ginger, wasabi, horseradish.

What it does to spices

Grating is grinding done to order, and it matters most for the spices whose aroma is most fugitive or whose pungency is made on damage. A whole nutmeg grated over a dish keeps the volatile compounds that pre-ground nutmeg has long since lost; fresh wasabi and horseradish have no heat until they are grated, reach their peak within minutes and fade within the half hour. The fineness of the grater changes the result: a very fine rasp bursts more cells and gives a sharper, more pungent pulp.

Culinary conventionFollows from the volatility and the damage-triggered pungency recorded for these spices, and from the Japanese practice of grating wasabi immediately before serving.Sources: On Food and Cooking: The Science and Lore o…

Why it works

A grater tears the material into very small particles, rupturing cells and exposing a large surface all at once. In nutmeg that releases the volatile oil for immediate use; in wasabi and horseradish it mixes myrosinase with the glucosinolate sinigrin in the presence of the plant’s own water, producing allyl isothiocyanate — which then evaporates, so the pungency peaks and declines within minutes.

Strong evidenceSources: On Food and Cooking: The Science and Lore o…; Chemistry of Spices

How it goes wrong

  • Grating wasabi or horseradish long before serving, by which time most of the pungency has gone.
  • Grating nutmeg in quantity for a dish that wants a trace: it is easy to add too much and impossible to take back.
Culinary conventionFollows from the timing of the reactions recorded above.

Spices it matters for

  • Nutmeg — Grated over béchamel, spinach and eggnog.
  • Wasabi — Traditionally on a sharkskin grater, which gives a finer, sweeter pulp.
  • Horseradish
  • Ginger — Fresh ginger grated for juice and pulp in Japanese and Chinese cooking.
  • Tonka bean — Grated in tiny amounts over desserts.

What it changes in the spice

The chemistry this technique sets off, explained in full on the science page.

What it is called

The same technique in the traditions that use it, each named in its own terms.

  • Samegawa oroshi

    Japanese

    A sharkskin grater for fresh wasabi.

  • Oroshigane

    Japanese

    A fine metal grater for ginger and daikon.

The tools it is done with

The equipment used for this technique, and the forms it takes in the kitchens that use it.

  • Grater

    Also called rasp

    A surface of fine teeth or rasps that shaves or pulps a rhizome, root or hard seed. It is the tool for the spices that are best used freshly grated — ginger, wasabi, horseradish, nutmeg.

    Culinary conventionEveryday kitchen equipment in the traditions named, described as it is used; no single publication is the authority for it.
    What it does to a spice:

    For wasabi and horseradish the grater makes the heat: their pungent compound does not exist until cells are broken and an enzyme meets its substrate, so the finer the grating, the more cells are broken and the more pungency forms. It fades within the half hour, which is why both are grated to order.

    Reasonable evidenceSources: On Food and Cooking: The Science and Lore o…
    History:

    Small nutmeg graters meant to be carried survive from the late 17th century: one of about 1690 made from a cowrie shell mounted in silver, and a miniature silver grater of 1698–99. Silver-and-steel nutmeg graters were made in the United States between 1780 and 1850, and in silver and iron in London and Birmingham from the 1780s to the 1840s, some shaped as barrels or melons; one of the 19th century is Chinese.

    Reasonable evidenceSources: Art Institute of Chicago — collection recor… (Object 1975.789: nutmeg grater, London, c. 1780/81, silver and iron); Art Institute of Chicago — collection recor… (Object 1975.790: nutmeg grater, Birmingham, c. 1842/43, silver and iron); The Metropolitan Museum of Art — Collection… (Object 1971.137: nutmeg grater, Chinese, 1800–1900, silver); The Metropolitan Museum of Art — Collection… (Object 205040: nutmeg grater, ca. 1690, cowrie shell and silver); The Metropolitan Museum of Art — Collection… (Object 202899: miniature nutmeg grater, 1698–99, silver); The Metropolitan Museum of Art — Collection… (Object 5412: nutmeg grater, United States, 1780–1850, silver and steel)
    • Oroshigane (Japan) — A metal or ceramic grater with fine teeth, used for ginger, daikon and wasabi.
    • Samegawa oroshi (Japan) — A grater covered in sharkskin, traditionally used for fresh wasabi, which reduces the rhizome to a fine, even paste.
    • Nutmeg grater (Europe and elsewhere) — A small, fine rasp for grating whole nutmeg directly over food.

    Used for Wasabi, Horseradish, Nutmeg, Ginger

Where it is used

The pairings that specifically call for this technique.

  • Nutmeg with spinach — A long-established European convention. Nutmeg's sweet warmth offsets spinach's mineral, slightly metallic edge, and the pairing extends to creamed spinach and to spinach in dairy-based dishes generally.
  • Wasabi with tuna — The canonical use, and the mechanism is the opposite of what people assume. Wasabi is not covering the fish — raw tuna at sashimi grade has very little to cover — it is providing a brief sharp contrast against a dense, fatty, faintly metallic flesh, and then clearing completely so the next mouthful tastes of tuna again. Its volatility is the whole reason it works here where a persistent heat would not.
  • Horseradish with beef — The defining pairing in both British and Central European cooking, arrived at independently in each. Beef is rich and mild and rewards something sharp against it, and horseradish supplies pungency without acidity or sweetness — unlike mustard, which brings its own flavour, or a pickle, which brings vinegar. Roast beef in England, boiled beef in Austria, and the same reasoning behind both.
  • Tonka bean with dark chocolate — The pairing that carried tonka into restaurant pastry. Chocolate is bitter and fat-rich, which suits an aroma that is intense, sweet and fat-soluble, and the almond-and-hay character reads as a more complex vanilla against it. Both survive baking, which vanilla-adjacent aromatics often do not.
  • Nutmeg with salt — The pairing that makes béchamel work, and the reason a white sauce without nutmeg tastes of flour. Salt raises the perceived intensity of aroma as well as of taste, and nutmeg is a warm, faintly sweet aroma with almost no flavour of its own — so a small amount of it, salted properly, reads as depth rather than as spice. The same relationship underlies nutmeg in mashed potato, in spinach and in a cheese sauce.

Questions this page answers

  • why grate nutmeg fresh
  • how to grate wasabi
  • fresh vs pre-ground nutmeg