Thyme vs Za'atar herb
The short answer
Closer than the oregano comparison, which is why it is asked. Origanum syriacum tastes noticeably of thyme — it is sometimes called Bible hyssop or wild thyme — and carries both thymol and carvacrol where common thyme leans on thymol alone. Common thyme is the better substitute for za'atar herb than Mediterranean oregano is, though the mixture sold as za'atar contains sumac and sesame and cannot be replaced by any herb alone.
Side by side
| Thyme | Za'atar herb | |
|---|---|---|
| Botanical identity | Thymus vulgaris L. | Origanum syriacum L., Thymbra spicata L., Satureja thymbra L., Thymus capitatus (L.) Hoffmanns. & Link |
| Part used | leaf | leaf |
| Origin | The western Mediterranean, particularly the dry limestone country of southern France and Spain. | The eastern Mediterranean and the Levant, where the plants grow wild across dry rocky hillsides from Turkey to Palestine, Lebanon, Syria and Jordan. |
| Flavour notes | warm, woody, savoury, faintly medicinal, earthy | herbal, woody, bitter, earthy |
| Heat | Scoville does not apply | Scoville does not apply |
| Flavour | Savoury, slightly bitter, persistent, and unusually good at surviving long cooking. It carries the taste of a stock or a braise without being separable from it, which is why thyme is in the classical bouquet garni alongside bay and parsley. | Savoury, herbal and slightly bitter, more astringent and less sweet than Mediterranean oregano and more rounded than thyme alone. It is not sour — the sourness in the blend is sumac — and it is not hot. On its own it is quieter than people expect, which is much of why it is nearly always used with sesame and salt. |
| Aroma | Warm, dry and faintly medicinal, with a clean woody edge — recognisably a relative of oregano but narrower and less pungent. Where oregano announces itself, thyme is a background that other things sit on. | Warm, herbal and distinctly thyme-like, with an oregano roundness behind it and a faint mineral dryness. It smells of hot dry hillside rather than of a garden herb, and it releases far more on being rubbed than on being opened. |
Which should you buy?
Thyme
Dried leaf, and it is one of the few herbs where the dried product needs no apology. Ground thyme brings the bitterness forward and loses the woody top notes within months. Fresh thyme is worth buying when you want the greener, more lemony version or when you want to fish a sprig out afterwards — but for a stock, a braise or a rub, dried leaf is doing the same job and keeping better.
Za'atar herb
Buy it rubbed rather than ground, and buy it from a Levantine grocer if you can, where the herb is sold separately from the blend and both are fresher and cheaper than a supermarket jar. The real buying decision here is not the form but which ingredient you are actually after: a great many recipes written in English say za'atar and mean the blend, and a jar of the plain herb used at the same quantity will taste thin and unsalted. If a recipe lists za'atar alongside sesame and sumac, it means the herb.
Full detail on thyme and za'atar herb, including evidence grades and sources for every claim above.