Sichuan pepper

• huajiao花椒

  Mandarin

  Huajiao is the numbing husk. It is unrelated to black pepper and to chillies, despite every English name for it saying "pepper".

• sansho

  Japanese

  Sansho is a closely related but distinct species with a sharper, more citrus character.

The flavour is citric, floral and mildly bitter, but the flavour is not the point. Within seconds of chewing a husk the lips and tongue begin to buzz — a genuine tingling numbness, closer to a mild electric current or a limb waking up than to any taste. It builds, plateaus and fades over several minutes. Nothing else in this dataset does this, and no amount of any other spice reproduces it.

Intensely citric — grapefruit and lemon peel — over a warm woody, faintly floral base. The citrus character is a family trait shared with the rest of the Rutaceae and is the first thing noticed on opening a fresh packet.

Red-brown open husks, rough outside and paler within, ideally with few black seeds among them. Green Sichuan pepper is a distinctly olive-green product from different material.

Light, brittle open husks that crumble easily. The black seeds are hard and gritty and should be sieved out before grinding — they will not break down and they carry bitterness.

• Hydroxy-alpha-sanshool — The numbing tingle, and the whole reason the spice exists. It stimulates touch and vibration nerve endings directly, which is why the effect feels mechanical rather than like a taste.
• Limonene — Much of the citrus aroma, as in the rest of the citrus family.
• Linalool and geraniol — The floral note behind the citrus.

Pick over the husks and discard stalk, thorns and as many black seeds as you can be bothered to remove — the seeds are grit and bitterness and contribute nothing. Dry-toast the husks for about thirty seconds until they smell strongly of citrus, then grind. Add ground Sichuan pepper late, because heat drives the effect off; add whole husks early if you are infusing oil, and strain them out. The commonest mistake is using an old ground jar and concluding the spice does nothing: test a husk on your tongue first. The second commonest is using it instead of chilli rather than alongside it, which produces a dish that tingles and has no heat — half of málà is not a version of málà.

Sichuan cooking above all — mapo tofu, dan dan noodles, water-boiled fish, hotpot, and the numbing chilli oils that go with them — where it works with chilli rather than instead of it. Beyond Sichuan it is a component of five-spice powder, and appears in braises, cured meats and stocks across Chinese cooking. It goes with chilli, garlic, ginger, spring onion, soy, fermented bean paste, pork, beef, tofu, aubergine and noodles. Japanese sansho and Nepali timur are used more sparingly, on grilled eel and in pickles and dipping sauces respectively.

• toasting — A brief dry-toast is close to mandatory. It drives off a slightly musty note, makes the husks brittle enough to grind, and lifts the citrus aroma. Thirty seconds over moderate heat is enough and burnt husks are bitter.
• grinding — Ground to order after toasting and sieving. Ground Sichuan pepper loses its numbing power noticeably faster than most spices lose their aroma, so a jar bought ground is often the reason someone concludes the spice does nothing.
• frying — Whole husks bloomed in oil at the start of a stir-fry, or infused into oil and strained out, transfer both aroma and numbness into the fat. This is how most Sichuan dishes deliver it.
• infusing — Steeped in hot oil to make a numbing oil, which is then used as a seasoning in its own right. A common restaurant preparation and a good use for husks past their best.

Put a single husk on your tongue and wait thirty seconds. Fresh Sichuan pepper buzzes unmistakably; old Sichuan pepper tastes faintly of citrus and does nothing. This is the most direct freshness test in the dataset, because the thing being tested is a physical sensation rather than a judgement about aroma.

• No tingling when a husk is chewed
• Faded brown rather than red-brown colour
• Little citrus aroma when the husks are crushed
• A musty or purely bitter smell

• Loss of sanshool activity, taking the numbing effect with it
• Volatilisation of limonene and the floral terpenes
• Oxidation towards a flat, faintly bitter character

Buy whole husks and buy them small. This is the strongest whole-over-ground recommendation in the dataset, because what fades is not merely the aroma but the effect: an old jar of ground Sichuan pepper is inert, and the usual conclusion drawn is that the spice is overrated rather than that the jar is dead. Sieve the black seeds out before grinding — they are grit and bitterness and nothing else — and toast the husks for half a minute first. Then test one on your tongue. Nothing else in this cabinet tells you so directly whether you have wasted your money.

• Whole husks, not ground — the difference in effectiveness is larger here than for any other spice in this dataset.
• Open red-brown husks with few black seeds among them.
• Little stalk and no thorns.
• A strong citrus smell on opening the packet.
• Test one on your tongue before cooking with it. If it does not buzz, it will not work.

Grading turns on colour, aroma and the proportion of seed, stalk and thorn remaining. Regional origin is used as a quality signal, Hanyuan being the best-known name. Species is generally not stated, so red and green product is distinguished by appearance rather than by label.

Rutaceae

A thorny deciduous shrub or small tree of temperate and montane Asia, bearing clusters of small reddish fruit that split open on drying to reveal a shiny black seed.

Temperate and montane East Asia, with China the centre of cultivation and use.

• China (Sichuan, Shaanxi and Gansu) — major producer. Hanyuan county in Sichuan carries a reputation comparable to a wine appellation.
• Nepal — notable producer. Timur.
• Japan — notable producer. Sansho.
• India (the Himalayan states) — notable producer

Fruit clusters picked by hand when they redden and begin to split. Timing determines both colour and numbing intensity, and picking is laborious enough to be a real component of the price.

1. Hand-picking — Clusters picked as the fruit reddens and starts to split.Why: The split husk is what is wanted; the timing sets the character.
2. Sun-drying — Spread and dried until the husks open fully and the seeds loosen.Why: Drying is what opens the husk and makes deseeding possible.
3. Deseeding and winnowing — The black seeds and any thorns and stalk are separated from the husks.Why: The seeds contribute grit and bitterness and no numbness. How thoroughly this is done is the clearest quality difference between a cheap packet and a good one.
4. Grading — Graded on colour, husk intactness, seed and stalk content, and aroma.

Graded on colour, aroma and — most visibly to a buyer — the proportion of seed, stalk and thorn left in. Regional origin functions as a quality signal, with Hanyuan the best known.

The commonest commercial shortcoming is not adulteration but underprocessing: packets sold with most of the seed still in, which is cheaper to produce and worse to cook with. Species substitution between Zanthoxylum species is routine and generally undisclosed.

Grown as a thorny shrub or small tree, often on terraces and slopes unsuited to other crops, and harvested by hand because of the thorns.

Temperate and montane rather than tropical. Altitude is associated with the more prized lots, and the plant tolerates cold winters that would kill most of the spices in this dataset.

Sichuan pepper is one of the oldest documented Chinese seasonings, in use long before chilli reached the country. This matters for how Sichuan cooking is understood: the numbing half of málà is the ancient half, and the chilli that now defines the cuisine in most people’s minds is a post-Columbian arrival of the last few centuries. Huajiao was the pungent spice of Chinese cooking when there was no other.

Overwhelmingly a domestic Chinese product and market, with Nepal, Japan and northern India producing related species for their own use. Export volumes are small relative to consumption.