“Adobo” is a Spanish word that literally translates to sauce, seasoning or marinade. In Spanish cookery, the basic ingredients for adobo are salt, pepper, oregano, garlic, vinegar and paprika. Before there was refrigeration, the mixture was used to preserve meat and fish. It was also used to pickle vegetables. In short, back then, it was a mixture for curing raw food. As Spain went on to colonize many parts of the world, the use of adobo spread to Latin America and other Spanish colonies.
The Philippines was a Spanish colony from 1521 to 1898. When the Spaniards arrived, they saw that the natives cooked their food with vinegar, garlic and peppercorns too and, because of some similarities with their adobo, the Spaniards referred to those native dishes as adobo. And that paved the way for the misconception that Filipino adobo is part of the Spanish legacy. It is not. In fact, despite the similarities in some of the ingredients, Filipino adobo is a stew, not a curing method. What it was called before the Spaniards arrived, no one knows today.
There are many regional variants of Filipino adobo but all share three ingredients in common — vinegar, garlic and peppercorns. In some regional variants, the salty component of the stew can be plain salt or patis (fermented fish sauce).
Meat or seafood is simmered in the mixture until it soaks up all the flavors of the seasonings and spices, and the liquid turns into a sparse thick sauce. That is Filipino adobo.
Soy sauce is a regional rather than a universal ingredient. Although adobo with soy sauce (adobong itim) has been more popular over the last hundred years or so, adobo without soy sauce (adobong puti) appears to be the original based on historical accounts on how the Spaniards described the dish that they encountered when they arrived. Variants of adobong puti are still cooked to this day — adobo sa dilaw, cooked with turmeric which gives the dish a distinctive yellow hue, is just one of many. So, it was very upsetting to see someone who calls himself an authority on Filipino food claiming on Anthony Bourdain’s No Reservations that soy sauce is an essential ingredient of Filipino adobo. What a clueless remark that was.
The most well known variants of adobo are the ones with pork and chicken but almost anything can be cooked using the basic adobo base of vinegar, garlic and peppercorns. For instance, you can make adobo with frog legs, oysters, catfish, rice, eggs, mushrooms, eel, with coconut milk, with lemongrass or with vegetables. It is even possible to cook vegetarian adobo. There is an eatery that dedicates itself to proving just how versatile adobo is and its versions include adobo topped with cheese. Seriously.