Thai curry pastes consist of a thick mixture of ground herbs and spices such as galangal, lemongrass, coriander, garlic, shallots and chilies. Thais will usually purchase prepared curry pastes from the market or supermarket, but recipes for making them from scratch also abound. In fact, many famous supermarket brands of curry paste started out as home-made versions by chefs. Although ready-made curry pastes offers convenience, there's no telling the age of the pastes in the market. The packaged pastes in supermarkets have also been stabilized such that they lack the subtlety of fresh pastes, so making the paste from scratch will probably offer the best in terms of taste. This is traditionally done using a large mortar and pestle, and it can take up to an hour to successfully pound all the ingredients.
Curry Pastes on sale in a Chiang Mai market.
The Thai word gaeng literally means “liquid”, although it is generally translated to curry. This is not surprising, since Thai curries are traditionally mostly liquid, with small portions of meat and vegetable for flavor, allowing a little meat to go a long way for families on a budget. Were it not for their spiciness, we might well be calling them stews.
Thai curries appear to have evolved over many centuries. The Mon—among the earliest settlers of Thailand—probably introduced the basic idea of blending spices into a paste and then combining them with coconut milk, meat and vegetables. The spices originally used are believed to be mainly black pepper and ginger. The arrival of the Tais (a Chinese ethnic group from which most Thais are descended) and other Chinese ethnic groups around the first millennium then introduced additional ingredients, but it wasn't until the 16th century that the Portuguese arrived with the chili pepper, now an essential ingredient of most Thai curry pastes.
We don't know much about Thai curries before the arrival of Westerners, as few of the early visitors to Siam (the country’s previous name) recorded their impressions of the food, although many of them apparently arrived with their own cooks and stuck to their own cuisine. The Abbé de Choisy, who accompanied the first French embassy to Siam in 1685 mentioned a meal only once. On 25 October 1685, he recorded:
"Tables had already been laid with a magnificent buffet, and many gold and silver vases. Gilded enamel is not held in esteem here. We dined at length. The Kings' [King Louis XIV of France and King Narai of Siam] healths were drunk to. There were Japanese-style stews, which I found good, the Siamese ones better, the Portuguese ones detestable."
Two hundred years later, we get another opinion on Thai food, also from a western diplomat, this time British. Sir Enest Satow C.M.G. was Minister-Resident in Bangkok from 1885 to 1888. He visited Chiang Mai in January 1886 and his comments on his first dinner with the King's Chief Commissioner in the north, Phaya Montri Suriyawong, are worth quoting at length for their insight into the Victorian viewpoint on the world:
"Of all places in the world where an evening suit was unlikely to be needed I thought Chiang Mai was one of the most improbable. Great was my horror then when I received a formal invitation to dine with Phaya Montri, and learnt that as the chief would be there, a tail-coat was expected of me. Luckily I had a black morning coat amongst my baggage, and my host was induced to accept it as a substitute for the garment prescribed by our etiquette. He has a pleasant private residence in the city, built of teak, and surrounded by a pretty garden. The drawing-room and dining-room were completely furnished in simple European style, and the dinner was provided by a Chinese cook. One of the best dishes was Siamese curry, which I prefer to all others that I have tasted. The predominant flavor is derived from lime peel, and it is very pungent, owing to the free use of chillies, but there is nothing in the world that comes up to it, not even the prawn curry of Ceylon. Phaya Montri is a man of taste, and his veranda was hung round with ferns and orchids. He is fond of bric-a-brac, and had already collected some fine Buddhist bronze statuettes, several of which were extremely ancient. His spittoons of silver repoussé work eighteen or twenty inches in height were magnificent, and cigars were brought round in a gold box such as Chinese workmen of Canton are famous for."