Konnyaku: The Chewy Konjac Jelly Used in Oden and Stews

A grey-white block that tastes of almost nothing yet shows up in nearly every Japanese simmered dish, and the reason is texture.

Published October 18, 2026 at 7:19 PM JST | By Tokyo Paul

Quick answer: Konnyaku is a firm, springy jelly made from the corm of the konjac plant, mixed with water and a mild alkali so it sets. It has almost no flavor of its own and is mostly water and fiber, so cooks use it for its bouncy bite and its ability to soak up broth in oden, stews and stir-fries.

What konnyaku actually is

Konnyaku comes from the konjac plant, a relative of the arum family that grows a starchy underground corm. The corm is ground or boiled into a paste, mixed with water, and then set with a small amount of food-grade lime or a similar alkaline agent. The result is a gel that stays solid even when simmered for a long time, which is unusual among jellies. Most of what you see in the package is water, with a fiber called glucomannan making up the rest.

Because the flavor is nearly neutral, konnyaku is eaten for what it does in the mouth. The texture is springy and slightly squeaky, closer to a firm rubbery custard than to gelatin. Newcomers sometimes expect a taste and find none, which is exactly the point: the block borrows the taste of whatever liquid surrounds it. It is a supporting player that makes a pot of food more interesting to chew.

A short history in Japanese kitchens

Konjac is generally understood to have reached Japan from continental Asia many centuries ago, and it was first treated more as a medicinal plant than as a food. Over time cooks worked out how to process the corm into a stable gel, and konnyaku became a regular ingredient in temple cooking, where plant-based dishes with satisfying texture were valued. By the Edo period it was an ordinary part of home simmering and street food.

A key advance was the method of making powdered konjac flour, which let producers make konnyaku all year instead of only after the autumn harvest. Gunma Prefecture is widely known as Japan's leading konjac-growing region, and many shops there sell fresh blocks, skewers and snacks. If you visit the area, konnyaku is a natural regional food to look for.

Block, noodle, ball and sashimi

The standard form is the rectangular block, called ita konnyaku, usually sold sealed in water. It comes in a pale grey-white version and a darker version flecked with black specks, which come from added seaweed or konjac skin. The two taste much alike; the dark one just looks more rustic. Shirataki, or ito konnyaku, is the thin noodle form, popular in sukiyaki and in light noodle-style dishes.

There are also hand-torn pieces, small knotted strips for stews, and round balls that are simmered in sweet soy broth. At the more adventurous end is konnyaku sashimi, sliced thin and eaten with vinegared miso or wasabi and soy sauce, where the texture is the entire attraction. In snack shops you may also find konnyaku skewers brushed with miso paste, a simple and filling item.

How it is cooked and why it needs a little prep

Fresh konnyaku has a faint earthy smell from the setting agent, so cooks usually blanch it first. Slice it, drop it into boiling water for a couple of minutes, and drain. This also firms the texture a little. Many recipes then score the surface in a crosshatch pattern or tear the pieces by hand, because rough, uneven surfaces catch broth far better than a smooth cut face.

After that the block is simmered slowly in a seasoned liquid, typically dashi with soy sauce and mirin, until it has taken on color and flavor. In nikujaga, tonjiru and other stews it sits alongside root vegetables and meat. In kinpira-style dishes, shredded or cut strips are stir-fried with sesame oil, soy sauce and a pinch of chili. Letting a pot cool and then reheating it gives the konnyaku even more time to absorb flavor.

Konnyaku in oden and winter food

The best-known place to meet konnyaku is oden, the winter pot of ingredients stewed in light dashi. Triangular or knotted pieces of konnyaku sit in the broth for hours, and they are a staple that nearly every oden shop and convenience-store counter offers. A dab of karashi mustard on the side suits the mild flavor well.

Konnyaku also appears in miso-based stews, in hot pots, and in the sweet-savory simmered dishes served at izakaya. Its popularity in cold months is partly practical, since it holds its shape in long cooking, and partly cultural: warm, soft-yet-chewy food is a comfort in Japanese winter eating. If you are new to it, oden is the gentlest introduction, because the dashi gives the block a savory base.

Buying and storing konnyaku

Supermarkets in Japan sell konnyaku in the refrigerated or chilled section near tofu, natto and other soy and starch products. Packages are usually sealed with the water they were set in. Once opened, keep unused pieces submerged in fresh water in a covered container in the fridge, and change the water every day or two. Check the label for the best-before date, and do not freeze it, since freezing changes the texture to something sponge-like and dry.

Overseas, shirataki noodles are the easiest form to find in Asian grocery stores and some regular supermarkets. They are often packed in a liquid with a noticeable smell, so rinse well and boil briefly before using. The block form appears in Japanese and Korean grocers, often labeled konjac or konnyaku.

Common mistakes and good pairings

The most frequent mistake is skipping the blanching step and then wondering why the dish smells odd. Another is cutting the pieces too large or too smooth, which leaves a bland center. Scoring, tearing and giving the pot enough time solves both. Do not expect konnyaku to be filling in the way rice or potatoes are; it adds volume and chew rather than calories.

For pairings, think of it as a sponge for bold seasonings: soy and mirin, miso, sesame, ginger, karashi mustard and chili all suit it. It goes well with daikon, carrots, burdock root, fried tofu and chicken. A small bowl of rice and a cup of hot tea or warm sake complete a simple winter meal.

A note on konjac jelly snacks: these cup-shaped sweets are firmer than ordinary jelly and are meant to be eaten in small bites. Follow the package guidance, and be especially careful serving them to young children or older adults.

Frequently Asked Questions

Does konnyaku taste like anything?

Very little. It has a faint earthy note before cooking, which blanching removes. Its role is texture: it turns springy and chewy, and it absorbs the dashi, soy or miso it is simmered in. That is why it works so well in oden and stews rather than on its own.

Is konnyaku the same as shirataki?

They are made from the same konjac gel. Shirataki, also called ito konnyaku, is the thin noodle shape, while ita konnyaku is the block. The texture and mild flavor are very similar, but the noodle form cooks faster and is common in sukiyaki.

How do you get rid of the smell?

Slice the konnyaku, then boil it for a few minutes and drain before using it. For shirataki, rinse under running water first. After blanching, the slight odor from the setting agent mostly disappears, and the pieces take on flavor better.

Keep Exploring

More guides from Tokyo Paul: Nikujaga: Japan's Meat and Potato Home Stew, Takenoko: Spring Bamboo Shoots and How Japan Cooks Them and Kishimen: Nagoya's Flat Udon Noodles.