Gū lǎo ròu(咕老肉)
This name is also sometimes used outside of China for a distantly related dish from Northeastern Chinese cuisine, named Guō Bāo Ròu (锅包肉) in Chinese. It consists of a bite-sized pieces of pork in potato starch batter, deep-fried until crispy. They are then lightly stewed in a variation of a sweet and sour sauce, made from freshly prepared caramel, rice vinegar and flavored with ginger and garlic, so the battering absorbs the sauce and softens. Beijing variant has the sauce thin and watery, while the dish as prepared in Dongbei itself often include thicker sauce with ketchup added to it, but both versions are characterized by an intense ginger and garlic flavor.
Sweet and sour pork(Chinese name: ɡū lǎo ròu, 咕老肉) is a Chinese dish that is particularly popular in Cantonese cuisine and may be found all over the world. A traditional Jiangsu dish called Pork in a sugar and vinegar sauce is considered its ancestor.
The origin of sweet and sour pork was in 18th century Canton or earlier. A record shows that the renowned Long Family in the prosperous neighbouring Shunde county (of the Qinghui Garden fame, and the family was active in the 18th and 19th centuries), used sweet and sour pork to test the skills of their family chefs. It spread to the United States in the early 20th century after the Chinese migrant goldminers and railroad workers turned to cookery as trades. The original meaning of the American term chop suey refers to sweet and sour pork.
Preparation
The dish consists of deep fried pork in bite sized pieces, and subsequently stir-fried in a more customized version of sweet and sour sauce made of sugar, ketchup, white vinegar, and soy sauce, and additional ingredients including pineapple, green pepper, (capsicum) and onion. In more elaborate preparations, the dish’s tartness is controlled by requiring that Chinese white rice vinegar be used sparingly and using ketchups with less vinegary tastes, while some restaurants use unripe kiwifruits and HP sauce in place of vinegar. Some of the more casual food outlets use diluted acetic acid as a substitute for white vinegar and synthesized red colouring in place of ketchup to keep the costs down, making the dish too pungent and leaving customers thirsty.
Hong Kong/Cantonese version
The Cantonese original is made with vinegar, preserved plums and hawthorn candy for a nearly scarlet colour and sweet-sour taste. A related Hong Kong/Cantonese-based dish is sweet and sour spare-ribs and it is identical in methods except spare-ribs are used in place of pork loins.
Northeast Chinese version