The cuisine of Việt Nam’s old imperial city of Huế features a number of local specialties that aren’t so well known in the rest of the country. The lightly fermented shrimp condiment called tôm chua, sour shrimp, is one of these. My in-laws tell stories of visitors from Sai Gon eyeing the plump pink shrimp in reddish sauce, wondering what main dishes it goes with and how to eat it.
Although the shrimp are fermented, they look so fresh you’d think they’d been caught moments before making their appearance on the serving tray.
My mother-in-law says the best tôm chua is prepared with shrimp grown in the brackish water of the Cầu Hai lagoon, about an hour outside Huế by motorbike. She says the carefully chosen shrimp are rinsed, their heads removed, and they are left briefly to marinate in rice wine, then transferred to a strainer to dry off. In the next step, they are combined with the necessary flavourings: thinly sliced garlic, shredded galangal and fresh bamboo, red chilis cut in thin lengthwise strips, sticky rice, and fish sauce. Amongst all the flavourings, galangal and chilis are the ones that give the tôm chua its characteristic flavour.
The ingredients are placed in a ceramic jar to ferment for seven to ten days in a cool place, preferably where the temperature can be kept steady. Some people even keep the jars buried to maintain the ideal cool atmosphere for the shrimp to ferment. The steadier the temperature, the tastier and more fragrant the final product. The fermentation turns the shrimp a reddish colour, as if they’d been cooked, the same way lemon juice or vinegar will “cook” fish.
At this point, the cook will add honey and maybe more galangal for extra flavour. Now, the shrimp are ready to bottle in clear jars that show off the lovely colours: pink or orange shrimp in red sauce dotted with yellow bamboo shreds, ruby red chilis and white garlic nubs. My mother-in-law says the condiment offers the perfect yin-yang balance, and all the important flavours: sweet, sour, bitter, and bùi (best translated as richness), linger on the palate.
Tôm chua is most typically served as a side dish with boiled pork sliced thin and arranged in overlapping concentric circles, and sautéed bean sprouts or boiled rau muống (water spinach). Alongside these, finely sliced local vả figs, a type of astringent green banana called chuối chát, and sour unripe starfruit top a pile of herbs including basil and coriander, and of course, more red chilis. The result is an eye- and palate-pleasing feast fit for the Nguyễn kings who once ruled Việt Nam (in some cases as puppets) from the old imperial city of Huế.