Derived from an ancient, hardy marsh plant called smallage (wild celery), celery seeds are light brown in color, with a scent that resembles grass or hay. The seeds have a strong, warm, bitter and astringent flavor and go well with tomatoes and vegetable juices. They are also included in commercial poultry seasoning blends and celery salt, and the warm bitterness of the seeds go well with foods such as fish, chicken, potatoes, shellfish, cheese, tomato, carrot and eggs.
Celery seeds should be used whole because of their small size, but also because ground seeds taste far bitterer than whole.
Use celery seed in dishes that benefit from its warm, bitter, celery-like flavor, such as soup stocks, boiling liquid for shellfish, mayonnaise dressings, or meatloaf.