Sunomono: Japanese Cucumber and Wakame

There is a small, cold, glassy dish that arrives at the start of almost every Japanese meal, wedged between the miso soup and the main event, and it does a quiet, important job. Sunomono, which translates simply as “vinegared things”, is the palate-resetter of the Japanese table: a few slices of pressed cucumber and a tangle of rehydrated seaweed, dressed in a sweet-sharp vinegar that wakes the mouth up and makes everything after it taste brighter. It takes twenty-five minutes, most of which is the cucumber sitting in salt doing nothing while you get on with the rest of dinner, and it is one of the most refreshing things you can put on a plate.

The dish that lives at the edge of the meal

Sunomono belongs to a family of Japanese salads called aemono and sunomono, dressed dishes that sit at the cooler, sharper end of the meal. Where a Western salad tends to be a substantial affair with its own presence, sunomono is deliberately slight: a small mound in a small bowl, meant to be eaten in a few bites. Its purpose is contrast. Set against grilled fish, rich tonkatsu or a bowl of rice, the vinegar cuts through fat and salt and leaves the mouth clean for the next mouthful. In a traditional multi-dish meal it functions as a kind of hinge, resetting the palate between richer plates.

The dressing that defines it is sanbaizu, one of Japan’s classic vinegar bases. The name means “three-flavour vinegar”, and in its simplest form it balances rice vinegar, sugar and soy sauce. Rice vinegar is the point of departure: it is gentle and slightly sweet, far softer than a European wine vinegar, which is why the salad tastes bright without being aggressive. Get hold of a Japanese or Korean rice vinegar if you can. The seasoned “sushi vinegar” sold in some shops already contains sugar and salt, so if you use it, hold back on the added sugar and taste as you go.

Wakame, the seaweed, does more than decorate. It is sold dried, in dark green shreds that look unpromising, and it rehydrates in cold water into soft, silky, deep-green ribbons with a clean marine flavour and a gentle slip on the tongue. It carries a natural savoury depth, the same glutamate-rich quality that makes a good stock taste of more than its parts, and it gives sunomono its faint taste of the sea. A little goes a long way: 10g of dried wakame swells into a surprising amount, so resist the urge to add more.

The salting step is the whole thing

If you make sunomono once and skip the salting, you will understand at once why it matters. Cucumber is about ninety-six per cent water, and if you dress the raw slices straight away they weep into the dressing within minutes, diluting it into something thin and watery while the cucumber itself turns limp. Salting first fixes both problems at once. The salt pulls water out of the cells by osmosis, which concentrates the cucumber’s flavour and, counter-intuitively, gives you a crisper, more resilient slice that stays snappy even once dressed. It also seasons the vegetable from the inside, so every bite tastes of cucumber rather than of dressing sitting on top of blandness.

Fifteen minutes is enough for thin slices. Longer does no harm, but do squeeze properly at the end: gather the slices in your fist and press hard over the sink, because any water left behind will end up in the bowl. This is the single technique that separates a limp, puddled salad from a crisp, glossy one, and it takes almost no effort. The same trick works on the cucumber that goes into a good tabbouleh, where excess water is equally the enemy of a bright, distinct salad.

The small clever twist: a whisper of miso

Classic sanbaizu is vinegar, sugar and soy, and it is lovely. The half-teaspoon of white miso I whisk in is my one quiet departure, and it earns its place. White miso, shiro miso, is the mildest and sweetest of the misos, fermented for a shorter time with a higher proportion of rice, and it carries a gentle, rounded savoury depth without tasting overtly of fermented soybean. Stirred into the dressing it dissolves invisibly and does something to the background of the dish, giving the vinegar something to lean against so the salad tastes fuller and more satisfying while staying every bit as light. Nobody eating it will point to the miso; they will just notice that this sunomono tastes of more than sugar and acid. If you cannot get white miso, leave it out and the salad is still excellent, but keep an eye out for a tub, because it lasts for months in the fridge and improves a great many dressings.

Getting the balance right

Sunomono lives or dies on the balance of its dressing, and rice vinegars vary in strength, so taste before you commit. It should read as sweet-sharp, with the sweetness rounding off the acidity so neither one dominates. If your first taste makes you wince, add a pinch more sugar; if it tastes flat or syrupy, a splash more vinegar will lift it. The soy should be present as a savoury undertone and a faint colour rather than a strong salty hit, which is why light soy is worth using over dark. Keep the whole thing on the delicate side, because this is a small refreshing dish and it is easy to overwhelm the clean flavour of the cucumber.

Variations worth trying

Once you have the base, sunomono opens up. The most common addition is kani, a little crab or imitation crab shredded through the salad, which turns it into something closer to a light starter. Thin half-moons of poached prawn work beautifully in the same way, as do slivers of blanched octopus if you can get it. For a vegetable version with more presence, add thin ribbons of carrot, softened in the same salt-and-press method, or a few paper-thin rings of sweet onion rinsed under cold water to tame their bite. A scattering of ito togarashi, fine threads of dried chilli, gives colour and a whisper of heat, while a few drops more sesame oil push it towards a nuttier profile. If you like the sesame direction, the same instinct drives a good sesame-ginger soba noodle salad, where toasted sesame and ginger carry the whole bowl.

Serving and keeping

Serve sunomono cold, in small individual bowls, as the first thing on the table or alongside a Japanese main. It sits happily next to grilled or teriyaki fish, katsu, or a simple bowl of rice, and its sharpness is exactly what you want against anything fried. It also makes an excellent light lunch component next to a piece of cold poached chicken, a role it shares with a good Vietnamese chicken and cabbage salad, which works the same trick of crunch and acid against lean protein.

It is best eaten within a few hours of dressing, when the cucumber is at its crispest and the wakame still has a little bounce. It keeps in the fridge overnight and is perfectly good the next day, though the cucumber softens as it sits in the vinegar and the whole thing relaxes into something gentler. If you want to prepare ahead, salt and press the cucumber, soak the wakame and mix the dressing separately, then combine everything just before serving so the crunch is at its best. The dressing itself keeps for a week in a jar in the fridge and is a useful thing to have on hand, ready to turn any spare cucumber into a cold, glassy, palate-clearing bowl in the time it takes to slice it.