Ajwain vs Caraway
The short answer
Both are small ridged Apiaceae seeds and the resemblance stops at the shape. Ajwain is dominated by thymol, so it tastes of thyme with an aggressive bitterness, and a very small quantity flavours a whole dish. Caraway is anise-like and warm from carvone, and is used far more generously. Ajwain is sometimes called carom seed or bishop's weed in English, which helps; being called "wild caraway" does not.
Side by side
| Ajwain | Caraway | |
|---|---|---|
| Botanical identity | Trachyspermum ammi (L.) Sprague | Carum carvi L. |
| Part used | seed | seed |
| Origin | The eastern Mediterranean and western Asia, with cultivation long established across South Asia, which is now the main producing region. | Western Asia and Europe, where it grows wild across a wide temperate belt and has been gathered and cultivated for a very long time. |
| Flavour notes | herbal, bitter, pungent, woody | sharp, anise, woody, bitter, cooling |
| Heat | Scoville does not apply | Scoville does not apply |
| Flavour | Hot, bitter and thyme-like, with a numbing sharpness on the tongue that fades quickly. It is one of the most assertive spices here by weight — a quarter teaspoon seasons a large batch of dough — and used generously it turns a dish acrid. | Assertive and slightly bitter, with a cooling sharpness and a lingering finish. Caraway is not a background spice: it is present in whatever it is added to, and a dish either tastes of caraway or does not contain it. People who dislike it usually dislike it definitively, which is worth knowing before adding it to something being cooked for others. |
| Aroma | Powerfully thyme-like, with a sharp medicinal edge and a faint anise note behind it. A jar opened in a kitchen scents the room. | Sharp, penetrating and immediately recognisable — the smell of rye bread. Anise-adjacent but drier and more medicinal than true anise, with a slight woody warmth behind it. |
Which should you buy?
Ajwain
Whole, and a small packet. Ajwain is assertive enough that most kitchens use it a quarter teaspoon at a time, so even a modest bag lasts years — and since it is cheap in a South Asian grocer and expensive in a supermarket jar, the sensible purchase is a small bag from the former rather than a large jar of anything. Crush a few before you buy if you can; spent seed is a documented problem and looks perfect.
Caraway
Buy whole, without hesitation. Caraway is nearly always wanted whole anyway — the seed is meant to be encountered in a bite of rye bread rather than dissolved into it — and the ground form both fades fast and reads as harsher. If a recipe wants ground caraway, grind it. And buy a small jar unless you bake rye: caraway is assertive enough that most kitchens use it slowly.
Full detail on ajwain and caraway, including evidence grades and sources for every claim above.