Bumbu is the Indonesian word for spices mixture or seasoning, and it commonly appears in the names of certain spice mixtures, sauces and seasoning pastes. It is commonly found in Indonesian cuisine, which includes its regional variants such as Balinese, Javanese, Sundanese, Padang, Batak and Manado cuisines. It is spread over various meats, poultries, seafoods and vegetables; used in stews, soups, barbecue, sotos, gulais, and also as a common addition to Indonesian-style instant noodles. The practice of blending spices, herbs and seasonings is perhaps the most distinctive feature of Indonesian cuisine; it produce some of the most flavorful food in the world.
Indonesians have developed original gastronomic themes with lemongrass and galangal, cardamom and chilies, tamarind and turmeric. The spice mixture is commonly made by slicing, chopping, grounding, beating, bruising, or sometimes burning the spices, using traditional cooking tools such as stone pestle and mortar, or a modern blender or food processor. The bumbu mixture was usually stir fried in hot cooking oil first to release its aroma, prior to adding the main ingredient (meats, poultry, or fish).
The main function of bumbu is actually the same as common spices; as flavouring agent, to add, enrichen and/or to enhance taste and aroma. However, in tropical Indonesian climate, prior to the discovery of refrigeration technology, the cooking and preparing food through spicing was used to kill the dangerous microbes and to improve food safety. The spices used in Indonesian bumbus such as garlic, shallot, ginger and galangal that are used in rendang have antimicrobial properties and serve as natural organic preservatives. Some of spices are known to inhibit the growth of microbes. That is why if cooked properly, dry rendang can last for as long as four weeks and still safe to be consumed.