What are double boiled soups?
In Cantonese culinary tradition, there are two distinct techniques of making soups. The bou (煲) process brings the soup or stock to a rolling boil over high heat, before lowering the flame to simmer for a few hours.
Double boiling or dun (炖) is a gentler process, to the bain marie technique in Western cooking, where soups are cooked in tightly covered ceramic pots within an outer pot of boiling water. While water should be replenished to maintain constant steam levels within the outer pot, the inner pot must not be uncovered until the end of its cooking time.
The Michelin Guide shares more about the double boiling technique, which is an elegant adaption of the ancient chamber cooking method that harnesses the boiling point of water to maintain gentle and even heat for cooking delicate ingredients.
Double boiling coaxes flavours from the ingredients and prevents liquid evaporation from the inner pot. The gentle release allows maximum retention of the soups' essence in terms of taste and nutrients, resulting in a more nutritious soup with greater depth of flavours.
This method is especially suitable for soups that are cooked for balancing and healing properties according to traditional Chinese principles of nourishment.