BEFORE greenhouses could supply year-round vegetables or fridges were introduced to prolong the life of vegetables, the sun was the best tool to preserve produce fresh from harvest for use in out-of-season months.

Even today, dehydration is still a prime method for preserving vast varieties of mushrooms and fungi that grow in specific regions across China. The light weight of the dried vegetables reduces air freight costs.

Chinese cuisine has become very versatile in the use of dehydrated vegetables. Take the Chinese white radish, for example. It’s a popular root vegetable with a slightly spicy taste.

The fresh white radish is served raw in salads or cooked in quick stir-fries to maintain crunchiness. It can also be added to soups and stews to absorb the flavors of meats while adding a bit of zest.

When the white radish is sliced and dried in the sun until most of its moisture evaporates, the texture becomes very chewy — ideal for pickling or use in slow-cooked stews and braised meat dishes.

In winter, drying white radishes strung in long threads or put in large baskets are a traditional sight in many rural areas around China.

Sun drying works with a large variety of common vegetables, including chilies, pumpkin, eggplant, long beans, kelp and day lilies. People living in the countryside typically dry a large quantity of their harvest and then store the vegetables in a dry, cool environment.

In Wuyuan County, Jiangxi Province, local residents dry baskets of produce in the sun, filling their rooftops with vibrant colors. This tradition is called shaiqiu, which translates into “sun dry autumn” because the peak season is in the fall.

While chilies can be dried whole, some vegetables require more elaborate preparation beforehand. Pumpkins are often cut in thin slices with the seeds removed, and eggplants are preserved in chunks. Drying white radish requires different cutting methods to create different textures in the dried vegetable.

One method is to put a white radish atop two parallel chopsticks, then cut it thinly at a 45-degree angle. The chopsticks prevent a full cut. When end is reached, the radish is flipped and the process repeated. Eased off gently, the white radish is turned into a flower shape and left to dry outside.

The day lily (Hemerocallis citrina), or huang hua cai in Chinese, is widely cultivated across China, particularly in regions south of the Qinling Mountains in northwestern Shaanxi Province.

The flowers contain colchicine, which can be poisonous when eaten raw. They cannot be consumed until they are first boiled in water. After that, they are sun dried.

The dehydrated day lily is common in Chinese cuisine. Packaged dried day lilies can be found in supermarkets at very affordable prices.

Another seasonal produce commonly preserved as a dry vegetable is the bamboo shoot. The spring shoots are boiled first, then the pieces are sun dried or baked dried. Different kinds of dried bamboo shoots retain different moisture levels. Some are completely desiccated, while others retain a certain percentage of moisture to preserve the tender texture.

Some vegetables in China undergo a curing process before they are set out in the sun to dry.

The potherb mustard is a popular mustard green with rich nutrients. It is used in making mei gan cai, a rich-flavored preserved vegetable.

Fresh potherb mustard is rinsed and dried for one day, then stored in a cool, ventilated place for four to five days. The mustard greens are turned every day to prevent them from going bad.

When the potherb mustard turns yellowish-green, it is put into pots or jars, with salt (3 kilos of salt per 100 kilos of vegetable) layered in between. The mixture is then pressed hard to squeeze out any juices. After curing, the mustard is taken out to dry in the sun.

Vegetables with extreme short shelf life, like mushrooms and fungi, can be dried in the sun directly to remove moisture. The commonly used varieties are shitake mushrooms and black fungus. In modern production, the mushrooms and fungi are also baked to dehydrate more thoroughly.

The key to bake-dry shitake mushrooms is to gradually bring up the temperature so that the mushrooms don’t instantly shrink. That process takes about a day.

Sea kelp dries naturally on beaches, but duplicating that process at home is hard work. The kelp is very heavy to pull up from the seabed, and farmers have to spend hours arranging it and then flipping it until the strings are fully dried.

Most dried vegetables can be cooked in the same way as fresh ones, after an initial step of rehydration. But even when dried vegetables return to their soft texture after soaking, they are much chewier than when fresh. That makes them ideal for absorbing sauces and condiments.

Different dried vegetables require different procedures. Shitake mushrooms take only about an hour to soften in warm water and should not be soaked too long. The residual water is packed with rich flavor and can also be used in cooking.

Black fungus and white fungus are best soaked in water at room temperature for eight hours. If that’s too much trouble on a regular basis, a larger quantity can be soaked and stored in the fridge in sealed containers or Ziploc bags.

Dried kelp requires even more effort. It should not be simply placed in water. The dried kelp must first to be rinsed well in water and then steamed for 30 minutes. Then it is washed again in warm water before letting it sit to soak for another 30 minutes.

Dried bamboo shoots also take longer preparation time. The hardest and driest varieties need to soak in water for at least one day, then are boiled until the thickest parts soften enough to be poked through with a chopstick. After that, the bamboo shoots must be rinsed three to five times in cold water.

Less dried bamboo shoots, like bian jian, are preserved from tender shoots and often retain more moisture during the drying process. They take a shorter time to soak in water, but beware the quantity of salt they may contain. Bian jian is often cooked in soups with duck.

A key to remember when dealing with dried vegetables is to rinse the produce thoroughly before soaking in water, constantly checking to see if the water needs changing.

Pork belly meat steamed with dried potherb mustard

Dried potherb mustard is often steamed with fatty pork belly slices layered on top in a southern-style dish called mei cai kou rou. It’s very popular around China and is best served with soft steamed buns or steamed rice.

Ingredients:

A cut of high quality pork belly meat, 700 grams

Dried potherb mustard, 150 grams

Dark soy sauce, 15 grams

Light soy sauce, 45 grams

Salt and sugar

A little honey

Several pieces of fresh ginger

Some green onion

One star anise

Cooking wine

Steps:

1. The big cut of pork belly is first boiled in water with ginger, green onion and cooking wine, then patted dry with paper towel.

2. Coat the meat with dark soy sauce and honey before letting it dry in a ventilated place.

3. Soak the dried potherb mustard in cold water until it softens, then rinse clean.

4. In a hot pan, fry several pieces of ginger in a few tablespoons of oil, then stir in the potherb mustard with some cooking wine, star anise, light and dark soy sauces, sugar and salt. Let the vegetables cook until the moisture evaporates and remove from pan.

5. In a clean pan, heat enough oil to cover the large meat chunks, fry the meat until the skin caramelizes and the sides turn golden.

6. Take out the meat and let soak in cold water for at least 15 minutes.

7. Cut the meat in slices about half a centimeter thick and arrange in a bowl. Then cover with the potherb mustard stir-fry mixture and steam for an hour.

8. Take a clean plate and cover the top of the bowl. Flip and the whole dish is ready to present, with the meat on top of the potherb mustard.