Pickles add a zing of flavor, a bit of crunch and typical Chinese breakfasts of congee and steamed bread seem incomplete without crispy, tangy pickles.
Salty, spicy, sugary, acidic pickles are not exactly loaded with health benefits, but they make a tasty garnish or side dish, contrasting with other ingredients, cutting through fat and adding texture.
There's a widespread belief in China that pickles are healthy in summer because they stimulate the appetite lost in hot and humid weather.
And in China, practically everything can be pickled, and is. They are mostly roots, stems, vegetables like small cucumbers, lettuce, cabbage, ginger, garlic, lotus root, peanuts, almonds, turnips, radish, to name a few.
Pickles are of three general kinds, jiang cai (酱菜, soy sauce vegetable), yan cai (腌菜, salt preserved vegetable) and pao cai (泡菜, salt spicy vegetable).
Among the famous pickles are Peiling (County) zha cai (榨菜, hot pickled mustard tuber) in Chongqing Municipality; Nanchong (County) dong cai (冬菜, dried mustard greens) in Sichuan Province, and jiang luobo (酱萝卜, soy sauce radish stem) in Yangzhou, Jiangsu Province; babao cai (八宝菜, eight-treasure pickles) in Beijing, and sauerkraut in Guizhou Province.
Pickling was originally used to safely preserve food, especially vegetables that were not available in winter, but later was developed for flavor.
The process typically involves water, vinegar, salt and sugar, plus spices. Soy sauce is also common.
Though Korea is better known for its pickles - notably fiery kimchi - Chinese pickles are far more diverse in ingredients and seasonings.
"Salty in the north, sweet in the south and spicy in the southeast" is the general picture of pickles in China, according to David Du, chef de cuisine at Hyatt on the Bund, who emphasizes the regional diversity.
Various pickles in Yangzhou are famous among southern pickles and known for being tasty, sweet, crisp and tender. It's said that Yangzhou pickles date back to the Han Dynasty (206 BC-AD 220) and spread to Japan in the Tang Dynasty (AD 618-907). Pickles are recorded in the imperial cuisine of the Qianlong Emperor in the Qing Dynasty (1644-1911)
Soy sauce, sugar and salt are common in the south where there's usually an insistence on high-quality ingredients. For example, small, soy pickled cucumbers must have thin skin, tender flesh and 30 pieces must weigh no more than 500 grams to ensure crispness and taste.
Similarly, in the south, ginger for pickling should be tender and not fibrous; luosi cai (螺丝菜, pickled Chinese artichoke) should be thin, crisp and well shaped; and turnips must be small, round and white for soy pickling.
Tenderness and small size are important south of the Yangtze River, where the land is fertile and crops are diverse.
The most famous pickles of North China are known as eight-treasure pickles, a combination in one jar of cucumber, kohlrabi, lotus root, cowpea, eggplant, Chinese artichoke, ginger and peanuts. They are salted, dehydrated and pickled with fine, sweet, soybean paste.
"Sour and spicy" are the words commonly used to describe the pickles in southwest China, consistent with the regional cuisine.
Nanchong dong cai is one of the four famous pickles in Sichuan Province; the other three are Peiling zha cai, Yibin (County) ya cai (芽菜, pickled sprout-like mustard greens) and Neijiang (County) datou cai (大头菜, pickled rutabaga).
The tender part of the mustard greens pickled in brine pickle are used for dong cai and the whole process takes from one to three years and involves around 20 steps. Spices include chili peppers, prickly ash peel (Sichuan pepper) and star anise, which are used in Sichuan cooking.
The popularity of pickles has resulted in a number of time-honored pickle shops. They include Sanhe Simei (三和四美, Three Harmonies and Four Beauties) in Yangzhou and Liu Bi Ju (六必居, Six Musts Shop) in Beijing.
"Considering that most of the pickle ingredients are vegetable roots or stems, they are not suitable for main dishes," says chef Du.
"However, pickles add flavor when working together in a meat dish," he adds.
Pan-fried shredded meat with wild rice and zha cai is a home-cooked favorite of many Chinese suffering from a poor appetite in summer.
A favorite in Sichuan cuisine is dong cai kou rou (冬菜扣肉, braised pork with preserved vegetables) and dong cai dandan mian (冬菜担担面, noodles with preserved vegetable and pepper sauce).
A favorite of Huaiyang cuisine is gua jiang yusi (瓜姜鱼丝, pan-fried fish pieces with pickled ginger and cucumber).
"The special pickle flavor adds more color to the fish taste, while the contrast between crispy cucumber and tender fish offers a variety of mouthfeel," says chef Du.
Still, pickles are, well, pickles, and there's not much you can do to innovate and make a better pickle. Most pickles today are the kind eaten hundreds or thousands of years ago.
"That's because of the less important role of pickles in fine Chinese cuisines, and it takes a lot of effort and time to innovate the already rich pickle categories in China," says Du.