Ajwain seeds are an Indian spice which come from the plant of the same name, also known as carom or bishop's weed. The spice appears in a variety of Indian dishes, and it has an intense thyme like flavor, along with a zesty kick, especially when used fresh. Stores which stock Indian spices will probably carry whole ajowan seeds, and they are also available through special order. Like other spices, ajowan seeds should be kept whole in a cool dry place until use for the best flavor. To determine whether or not they are still good, crush them lightly to see if they still smell strong.
The botanical name for the plant is Trachyspermum ammi, and it is in the family Umbelliferae, along with dill, caraway, and cumin. Like the seeds of these plants, ajwain seeds are small and roughly crescent shaped, with a silky thread at one end of the seed. The bush-like plant has feathery leaves and red flowers, and grows up to two feet (61 centimeters) in height. It prefers hot, dry climates.
Some people eat ajwain seeds raw and whole, crunching them between the teeth. The flavor of raw seeds is hot, fiery, and bitter, and it can leave the mouth slightly numb. When cooked, the intensity of the flavor is mitigated, allowing more of the thyme-like flavor to rise in the dish. Ajwain seeds are used in a wide range of Indian dishes from breads to curries, along with an assortment of other herbs and spices.
Ajwain Seeds is just the Indian name for celery seeds.