Miso is a blend of soybeans, grain, salt, and Aspergillis orzyae, a benevolent mold. It ranges in color from creamy ivory and pale yellow to soft ochre, burnt siena, and earth-black. Often compared to peanut butter in texture, miso can be dry and pasty, moist and smooth as apple butter, crumbly as potting soil, or nubbly with bits of bean and grain. In flavor, miso ranges from decidedly sweet to meatlike with coffee or cocoa notes. The layers of flavor, the result of fermentation, are what make miso an ideal enrichment in meatless dishes, where it instantly adds the kind of depth a good stew develops only after it has simmered for hours.

If soy sauce offers a trio of brightness, salt, and yeasty flavor to a dish, miso is a culinary orchestra, offering a profound harmony of complex flavors, including evanescent top notes, a sweet or dry body that linger, and unique grace notes. Miso also adds a creaminess and body to the texture of dishes. Finally, if offers health benefits, both as a fermented food rich in enzymes that aid digestion and as a soyfood containing protein, which soy sauce and tamari do not.

When produced the way it has been for centuries in Japanese farmhouses and miso shops, where it is allowed to ferment as nature takes its course, no two batches of miso are alike. Their differences come from the specific qualities of the soybean crop in a given year, the specific qualities of an equally variable crop of grain, usually barley or rice, and the variations of temperature and humidity that take place while enzymes from friendly bacteria are busy digesting the sugars in the soybeans and grain, This is not true of industrially manufactured miso, where artificially controlled temperatures and careful monitoring assures uniformity as well as faster fermentation than by the traditional method.

Miso has qualities that let it take the place of both wine and butter in cooking. Darker misos have the layered flavors you get when cooking with wine. Miso does not taste like butter, but mashed into potatoes, carrots, and other root vegetables, a light miso makes them creamy and imparts a satisfying richness, without fat.

When cooking with miso, keep in mind that the paler ones taste sweeter and less salty, while darker misos are saltier and more intense. For example, sweet white miso, almost ivory in color, contains only 5.5 per cent salt, while chocolate-dark Hatcho miso contains 10.5 per cent.

When buying miso, it helps to know that among all those tubs and jars, there are three major families of miso and more than a dozen varieties. The kind of grain used determines the family a miso belongs to. Rice miso is made with rice and soybeans. Barley miso combines barley and soy. Hatcho miso contains only soybeans. Often, the name of a miso relates to the prefecture or town where it was fist made, as in Dendai or Hatcho miso. The amount of time it has fermented is also a factor in defining what variety it is.

Until you have some experience with miso, I recommend buying it in a natural food store, where the miso is usually good and naturally made. The products they carry will have English names, which are often descriptive, like mellow white miso. In Asian stores, where there is usually little or no English on the label, you can buy miso by color–light, medium, or dark–but you have no way of knowing if it contains preservatives, bleach, or additives like riboflavin, used for coloring. On the other hand, miso clearly labeled as organic is being sold in a growing number of Asian markets.