Indonesian Vegetables: Leaves, Gourds and Beans Compared

Indonesian vegetables cover far more ground than the salad greens most visitors expect. Leaves that grow at the edge of water, climbing gourds with ridged skins, tree pods eaten while still young, bamboo shoots that must be cooked through and a breadnut that cooks like a starch all sit on the same market table. The fifteen vegetables here are best understood by the part of the plant that reaches the pan, because that choice decides how long a vegetable cooks, whether it needs salt, and whether it needs heat before it is safe. The vegetables below fall into families, and each one comes with notes on how to choose and prepare it. For the wider picture of dishes and eating habits, the Indonesian food guide sets the scene.

Indonesian vegetables: what the category covers and why it matters

The category is not defined by botany. Some are true vegetables in the kitchen sense, such as cabbage, cucumber and green beans. Others are fruits that cooks treat as vegetables, such as chayote, pare and the breadnut. A few are leaves from plants that most people would not think of as salad material at all, such as the leaves of the leucaena tree. Grouping them by function rather than by family makes sense for a visitor, because a leafy green is cooked very differently from a hard gourd, and a bean pod needs a different method again.

Three questions help when you meet an unfamiliar name on a menu or in a market. First, is it leaf, fruit, pod or shoot? Second, is it eaten raw or only after cooking? Third, does it carry a bitterness or a natural toxin that a cook must remove? The sections below answer those questions for each vegetable in turn.

Leafy greens and water plants: the quick-cooking group

Genjer, the water green of Java

Genjer is an aquatic plant, and the whole top of it is used as a green. The stalk and leaves go into soups, curries, salads and stir-fries, and the immature flower buds are eaten too. The most common home preparation is a short stir-fry. Cooks cut the genjer into pieces of about three centimetres, fry a paste of shallot, garlic and kencur with red chili, then add oncom or tempe with a little water. The leaves go in last, with salt and palm sugar, and cook only until they are tender.

Genjer also carries a cultural weight that the recipe does not show. A song from the 1940s, Genjer-genjer, sung in the Banyuwangi language of East Java, describes the plant as food people turned to in hard times. The vegetable is still remembered as poor people’s food, and its mild, flat flavour is part of why it was eaten when little else was available. That history makes it a good first green to learn, because the dish is simple and forgiving.

Katuk, the shrub with dense dark leaves

Katuk is a shrub that can reach about two and a half metres, and its dark green oval leaves are five to six centimetres long. Across South and Southeast Asia it is one of the most widely eaten leaf vegetables. In Malaysia the leaves are commonly stir-fried with egg or dried anchovies. In Vietnam they are cooked into soup with crab, minced pork or dried shrimp. In Indonesia the leaves turn up in everyday dishes, in herbal drinks and in nutritional products, and Javanese and Sundanese households have long used the plant in jamu, the traditional tonic, to help with breast milk.

The one caution that matters with katuk is raw consumption. Eating large quantities of uncooked leaves, or drinking them as raw juice, has been linked to serious lung problems. Cook the leaves, keep portions moderate, and treat raw juice as something to avoid rather than a health shortcut.

Krokot, the purslane with a sour edge

Krokot is the Indonesian name for purslane, a low succulent plant that grows in gardens, along field edges and on waste ground. Every part of the plant is edible, and the stems and leaves taste slightly sour and salty. Their sourness comes from oxalic acid, so take care with large amounts, and be cautious if you have had kidney stones. The usual preparations are a fresh salad, a quick stir-fry, or a soup where the mucilage in the leaves thickens the broth.

Because krokot grows wild and in small home plots, the cook who serves it is usually the person who grew or picked it, and that is the best person to ask about the plant.

Caisim, the mustard green of quick stir-fries

Caisim is a mustard-type green that Indonesian cooks reach for in quick stir-fries. Recipes often list it alongside choisam or paksoy, which shows how many names the same kind of leaf carries across markets. In a typical tumis, the cut leaves go into hot garlic oil with softened straw mushrooms, a splash of oyster sauce and a little water. They are ready when the stems soften and the leaves wilt, and they should not be left to stew.

The wider mustard group is most often stir-fried or pickled. The Chinese leaf mustard known in Southeast Asia as gai choi belongs to the same species, and the leaves are also used in a sour stew of mustard greens with tamarind that is popular in the region. Caisim suits any dish that needs a bright, slightly peppery green in a few minutes.

Bayam, the soft leaf for clear soup

Bayam is the word cooks use for soft leaves that go into light soups. In a common clear soup, the leaves go in after pumpkin has partly softened in the broth, seasoned with shallot, garlic, white pepper, sugar, salt and a little powdered stock. The leaves are rich in vitamins A and C, and they also supply calcium and manganese. They contain a lot of oxalic acid as well, which the calcium in the leaves partly offsets. For that reason, rinse the leaves well and do not make them the main raw green in a meal.

The same leaf family also appears in Vietnamese soups, where cooks use the leaves mainly in broth. Because the name covers more than one kind of leaf, it helps to ask the cook which green is being served.

Gourds and fruit vegetables: from bitter to mild

Pare, the bitter gourd of everyday kitchens

Pare, the bitter gourd, has a warty oblong skin and a crunchy, watery flesh that tastes like cucumber with a bitter edge. In an unripe fruit the seeds and the white pith are much less bitter than most visitors expect, and cooks normally remove them before cooking. In Indonesia the fruit goes into gado-gado, into stir-fries, into coconut-milk dishes and into steamed preparations. The most typical home dish is oseng-oseng pare, a Javanese stir-fry with shallot, garlic, chili, shrimp paste and a little tomato, and it is served with rice as an everyday side.

Cooks who want a less bitter result use the larger Chinese variety of the fruit, and they salt the sliced pare to draw out moisture and bitterness. The method is to sprinkle the slices with salt, leave them for about fifteen minutes, and rinse them thoroughly under cold water before they go into the pan. The fruit is available all year in Indonesia, so the method is worth learning rather than waiting for a seasonal window.

Oyong, the sponge gourd in clear soup

Oyong is the angled luffa, and it is picked young, while the skin is still smooth and the flesh is tender. Harvest for eating can begin about two weeks after the flower sets into fruit, and older fruit turns fibrous and bitter, so cooks choose small, heavy gourds with unmarked skin. In the kitchen the tough outer skin and its ridges come off with a knife or peeler, the fruit is washed and sliced, and then it needs only brief cooking because it is already tender.

The classic dish is a light soup of oyong with cellophane noodles, garlic and mushroom stock, often made without meat. It is an everyday home dish and a common childhood food in Java. The young leaves and flower buds of the plant are eaten as well, so a cook may use more of the plant than the fruit alone.

Chayote, the pear-shaped labu siam

Chayote, called labu siam, which means Siamese gourd, is a pear-shaped fruit in the gourd family. It has a single large, flattened seed inside, and that seed is edible and has a nutty taste. The starchy root is eaten like yam or potato, and the young leaves are a popular green in Indonesia. The fruit itself is treated much like summer squash, and in Indonesian cooking it appears in lalap, sayur asem and sayur lodeh.

In a sambal goreng, the chayote is halved, the halves are rubbed together to remove the white sticky sap, and the flesh is cut into thin strips and salted before rinsing. The strips are then braised in a coconut-milk gravy with fried chili paste, galangal and salam leaf. A gentle simmer of about seven minutes is enough to leave the strips soft while they still hold their shape.

Labu kuning, the yellow pumpkin of soups

Labu kuning is the yellow pumpkin. It came from the tropical Americas and is grown for its flesh, its flowers, its greens and its seeds. In Indonesian cooking the orange flesh gets most of the attention, but the young leaves are cooked too. A sour soup, sayur asam, uses about 250 grams of diced labu kuning with about 50 grams of young pumpkin leaves. The broth is sharp from young tamarind and seasoned with chili, shallot, galangal and salam leaf, and the pumpkin is cooked until it is soft, a process that takes around half an hour. The sweet pumpkin against the sour broth is the point of the dish.

Cucumber, the timun of salads and stews

Cucumber, known as timun or mentimun, is believed to have come from the foothills of the Himalayas. In Indonesia and across Southeast Asia, most cucumbers are eaten raw in salads with a dressing. The large yellow types are boiled and added to stews. Young shoots of the plant are eaten raw or steamed, and they are also stir-fried or used in soup.

Pickled gherkins are less common in Southeast Asian kitchens than in Europe. Indonesia does grow small gherkins, mainly for export, and very young local fruit is the form used for pickles. If you are choosing between cucumber dishes, the salad is the simplest and the stew is the most filling.

Cabbage, a cool-season crop

Cabbage is a cool-season crop. Its best growth comes between about 4 and 24 degrees Celsius, which is why it is widely grown in temperate regions. In tropical Southeast Asia it is a minor crop, usually grown at higher elevations where the climate is cooler. That is why the cabbage grown in the region is tied to higher ground rather than the valley floor. Cabbage can be steamed, stewed, sautéed, pickled, fermented or eaten raw, and each method suits a different texture.

For a visitor, the practical point is simple. When cabbage appears in a dish, ask where the leaves were grown, because the climate that grew them shapes how crisp and sweet they are.

Beans, pods and shoots: the group that must be cooked through

Buncis, the Indonesian green bean

Buncis is the Indonesian name for the common green bean. The immature pods are the part eaten as a vegetable, while the mature dry beans are a separate product that needs its own preparation. Raw or undercooked beans contain phytohaemagglutinin, a protein that causes nausea and vomiting within a few hours. Dry beans must be soaked and then boiled at full heat for a sustained period to destroy it. Fresh green beans need less time, but they still have to be cooked through rather than served crisp.

Lamtoro, the leucaena tree in village food

Lamtoro is the leucaena tree. In Javanese it is called lamtoro, in Sundanese pelending, and in Indonesian petai cina. The young pods are eaten raw or cooked, and they appear in a Javanese vegetable salad served with a spicy peanut sauce. The seeds and young leaves contain mimosine, a toxic amino acid, and the concentration is highest in growing tips and young pods. Cooking removes most of the toxin, so cooked pods are the safer way to eat lamtoro. Treat raw tree parts with caution, and do not eat the leaves raw.

Rebung, bamboo shoots that must be cooked

Rebung is bamboo shoot, and it is the one vegetable in this group that cannot be eaten fresh. Raw shoots contain cyanogenic compounds, so they must be thoroughly cooked. Indonesian cooks slice rebung thinly and simmer it in coconut milk. Gulai rebung, the Padang curry, is built on lemongrass, galangal, turmeric, candlenut and salam leaf, and the shoots simmer in that broth until they are cooked through. The same vegetable turns up in sayur lodeh and in fried wrapped preparations. The thin slice helps, but the cook still has to make sure the shoots are fully cooked.

Kluwih, the breadnut that cooks like a starch

Kluwih is the breadnut, a relative of breadfruit. It is the seeded form, while the breadfruit that is more widely planted is largely seedless. Indonesian names separate the two: sukun for the seedless type, and kelur or timbul for the seeded one. The breadnut is native to New Guinea and possibly to the Moluccas and the Philippines, so it belongs to the eastern side of the wider Indonesian region.

Immature seeded fruit can be cooked as a vegetable. In the Philippines it is cooked with coconut milk, and the seeds are eaten after boiling, roasting or frying. Kluwih is the vegetable here that behaves most like a starch, so it fills a plate in a way the leafy greens do not.

How the vegetables differ at the cooking stage

Cooks sort these vegetables into roughly four working groups, and the group tells you the method.

• Quick greens that wilt in minutes: genjer, katuk, krokot, caisim and bayam.
• Soft fruits and gourds that cook gently in broth or sauce: oyong, labu kuning, chayote and cucumber.
• Bitter or pithy fruit that needs salt, rinsing or seed removal: pare.
• Pods, shoots and beans that must be cooked fully to be safe: buncis, lamtoro and rebung.

Two vegetables sit outside those groups. Cabbage is a cool-season crop that suits higher ground, and kluwih is a starchy fruit that cooks like a root. Both fill a different role on the plate, so a meal built from only leafy greens will feel light, and one built from gourds and kluwih will feel heavier.

How to choose between them at a market or a restaurant table

When you are choosing, start with the texture you want. For a crisp raw side, cucumber and the young leaves of katuk are straightforward, provided the katuk is cooked or eaten in modest portions. For a soup, oyong and the leaves that suit clear broths are the easiest choices. If you want something bitter that still balances a meal, pare is the vegetable to order, especially if the cook has salted it. If you are unsure about safety, choose a dish where pods, shoots or beans have been cooked for a long time, because that is the part of the group where undercooking causes the most trouble.

If a dish is new to you, ask what part of the plant it uses. A leaf dish will taste green and light. A fruit dish will taste sweet, sour or bitter depending on how ripe it is. A pod or shoot dish will usually be cooked in coconut milk or a braise, which softens any harsher notes.

Preparation rules that apply across the group

Four rules cover most of the cooking decisions in this group. First, cook beans, bamboo shoots and lamtoro through, because each carries a natural compound that heat destroys. Second, salt and rinse bitter fruit such as pare, and remove seeds and pith where the recipe asks. Third, peel the tough outer skin of gourds such as oyong and the chayote, because the peel holds bitterness and fibre that the flesh does not. Fourth, limit raw portions of the leaves that contain oxalates or other compounds, including bayam, krokot and katuk.

None of these rules is complicated. They matter because the vegetables in this group were not bred for the uniform supermarket market that most visitors know. Their flavour and their safety depend on how they are handled, and the cook who knows the rule for each vegetable gets far better results than one who treats them all the same.

Where these vegetables sit on an Indonesian table

Most of these vegetables are not served alone. A plate of rice with a green, a gourd or a bean dish and a spoon of sambal is the usual pattern, and the vegetable often carries the lightness and the balance that the meal needs. Learning the vegetables one part at a time, from the quick greens to the cooked-through pods, is the fastest way to read a menu with confidence. Start with the group that suits your own kitchen, let the part of the plant guide what you buy, and let the rules above decide how you cook it.