Cooking with Ajwain Seed
When collecting spices, there comes the eventual risk of flavor overlap. Will that new spice taste significantly different from what I already have? Is it really worth the diminished pantry real estate? I sometimes find myself confronted by these questions, and invariably I give in. An ounce is less than a dollar, I say. Just an ounce. Fortunately, with spices, the risk is usually worth it.
Ajwain plays a little like a greatest hits album of more common herbs and spices. It tastes unmistakably like thyme, but it's got some oregano-like pungency, a bite reminiscent of cumin, and an aftertaste that may remind you of anise. But ajwain is an assertive, distinct spice all its own. It pulls those flavors from their familiar grounds and combines them into something utterly new.
A member of the parsley family (the leaves are also edible), most ajwain today comes from India, and is widely used in a variety of dishes there. It also goes by the names carom and bishop's weed. It's another one of those spices used to treat a range of health problems; my favorite claim is a triumph of delicate wording: it supposedly "temper[s] the effects of a legume-based diet."
What Does It Taste Like?
Ajwain's main flavor comes from thymol, the essential oil that makes thyme taste like thyme. But while thyme is floral and sweet, ajwain is more sharp and pungent. It lifts flavors like thyme, but also acts as a strong contrasting element in simmered vegetables, beans, lentils, and breads. Its unique bite is a great way to add complexity and interest to the aromatic base of a curry or as a finishing tarka, in which spices are briefly fried in hot oil or butter before being poured on a finished dish, just before serving. Ajwain doesn't need to be fried before using—you wouldn't for bread—but it should at least be dry-roasted to excite its flavors before use.
How Do You Use It?
A little ajwain goes a long way—a teaspoon is enough for a large pot of food. You do, however, have some control over how it affects a dish. In dishes rich in starch and fat (such as Indian-style fried potatoes), where its sharp cutting side may be especially valuable, you can add ajwain at the end, either raw or briefly fried in fat.
I prefer the effects of longer cooking achieved by starting a dish with fried ajwain: its pungent thyme-ness mellows and its haunting aftertaste becomes more pronounced. It still stands on its own rather than blend in with other spices, but its more complex, subtle flavors are also allowed to bloom. Like many small-grained spices, you don't need to grind ajwain to release the bulk of its essential oils.
Though ajwain remains rooted in Indian cuisine, don't let those boundaries stop you. It's great in parathas but equally delicious in ciabatta-like breads. Vegetables that tend towards slight bitterness are improved by its inclusion, as are potato chips and spice blends used to season deep-fried food. Ajwain may remind you of other spices in your pantry, but nothing plays quite like it.