Using “Indonesian food” as a blanket culinary term is about as useful as talking about “American food.” Just as our cuisines differ—sometimes significantly—by region and state, Indonesian cooking varies even more wildly across the roughly 17,508 islands (but who’s counting?) that comprise this archipelagic state.

Not prepared for quite that much island hopping—yet still hoping for a microcosmic taste of this macrocosmic culinary scene—I focused my eating in Jakarta, the nation’s capital and a hub so central to so much of Indonesia’s political, business and cultural pulses, nearly all of the country’s cuisines can be found there in some form or another.

It was the right call. Because as I devoured more nasi goreng, satay, bakso, rendang, mie goreng and gado gado than I thought possible in a week, common threads revealed themselves. I’d be hard-pressed to connect the dots of the coastal cooking of Maine, Louisiana and California, but in Indonesia it became clear that one thing underpinned most everything.

Bumbu.

The term translates simply as spice, but especially refers to spice pastes, potent blends of alliums, aromatics, chilies, spices and nuts that provide the flavor backbone of so many dishes. The specific combination of ingredients and their volumes, whether pureed or simply ground, if cooked before or after grinding, all determine the flavor and intensity a paste delivers.

“You can do so many things with just one spice paste. Each paste can make multiple dishes, even with the same protein,” explained Degan Septoadji, a chef and judge on MasterChef Indonesia. Despite all that variation, most spice pastes can be categorized into one of five—white, yellow, green, red and black. The darker the color, the deeper, more potent the flavor.

Long ago, those colors also had cultural meaning that influenced when they were used. “Yellow was the color of wealth,” Septoadji said. “You’d use it for certain ceremonies.” Red was for good fortune, green represented hope, white indicated purity, and black symbolized wisdom. Today, of course, it’s more about taste and all the pastes are used widely.

Nearly every paste begins with the same base—garlic, shallots, ginger, galangal, lemon grass and sometimes candlenuts (similar to macadamias). The ingredients added after that determine the color and flavor. White—called bumbu dasar putih—contains only those basics, and the flavor is clean, creamy and almost miso-like. It’s often used to marinate chicken.

Yellow—or bumbu dasar kuning—gets color and earthy-savory notes from the addition of fresh turmeric. It often is used as a base for soups. Green—bumbu dasar hijau—is spiced and colored by fresh green chilies. It is popular for stir-fried chicken or rice, as well as steamed seafood. Red—bumbu dasar merah—owes its color and sweet notes to palm sugar and red chilies; it’s commonly paired with tempeh to create either a glaze-like coating or a soupy broth. Black—bumbu kluwak—gets color and nutty flavor from a fermented black nut called kluwak. It’s often paired with beef.

Traditionally, all bumbus are prepared using a cobek and ulekan, a wide, platter-like stone mortar with an angled, heavy pestle. The shape and technique—the ulekan is used to smash and drag the ingredients across the cobek—reflect the tough, fibrous nature of many of the ingredients in bumbu, Septoadji said. Up-and-down mashing isn’t enough.

Tasting my way through the pastes can only be likened to welcoming a series of increasingly intense explosions in your mouth. Raw, they all were pleasantly pungent. But once cooked in oil or broth, they bloomed and the flavors deepened. “The only difficult part of cooking Indonesian food is making the spice pastes. Once you understand that, it’s very easy.”

And frankly, even making the spice pastes wasn’t that hard. Though Septoadji prefers to use a cobek and ulekan, many cooks use a blender, making it fast and easy to harness a seemingly limitless multitude of flavors. Suddenly, those 17,508 different cuisines didn’t feel nearly so overwhelming.