Rosemary vs. Thyme: Piney and Strong vs. Savory and Medium

Out of rosemary? Thyme can usually stand in at an equal amount, but rosemary should replace thyme only at a reduced one. The University of Delaware’s extension service puts rosemary among the strong herbs and thyme among the medium ones.¹ Both are woody mint-family herbs that go into the pot early, and they often end up in the same one. Underneath, though, they’re built on different chemistry: rosemary oil is led by α-pinene and 1,8-cineole, while most thyme oils are led by thymol.

Side by side

Rosemary’s leaves taste pungent and slightly bitter, and PROSEA links rosemary’s warm, piny note to α-pinene.²

The chemistry, sample by sample

Each figure belongs to the oil it was measured on. They come from different studies and describe distilled oils, not dried leaf, so don’t merge them.

The 2017 rosemary study found at least five chemotypes,³ and PROSEA reports thyme chemotypes where thymol and carvacrol are both below 5%.⁴ Still, the usual pattern is clear: the two herbs share no lead compound. They taste different, even though they often end up in the same pot.

The differences that change a dish

Strength

The University of Delaware groups rosemary with bay, sage and mustard among the strong herbs, and thyme with oregano and mint among the medium ones. For that strong group, it warns that the flavor “can be extremely objectionable” if you use too much.¹ A Couple Cooks calls thyme much milder than rosemary.⁶ Bottom line: go lighter with rosemary.

Cooking

America’s Test Kitchen counts both as hearty herbs to add early, because their flavor compounds are somewhat more heat-stable.⁷ In ATK’s dried-versus-fresh tests, dried rosemary and dried thyme both held up reasonably well in dishes with more than 20 minutes of cooking and a good amount of liquid.⁸ LSU AgCenter also lists both among the less delicate herbs.

Texture

Rosemary’s leaves are needle-like, up to 5 cm long and only 1–2 mm wide. Thyme’s are 3–8 mm. Thyme leaves can go into a dish whole. Rosemary usually gets chopped fine, or goes in as a sprig you fish out later.

They often go together

McCormick’s culinary poultry seasoning lists thyme, sage, marjoram, rosemary, black pepper and nutmeg, in that order,⁹ and US labels list ingredients in descending order by weight,¹⁰ so that blend has more thyme than rosemary. In the Label Rouge recipe for herbes de Provence, as reported by the French trade press, rosemary makes up 26% and thyme 19%.¹¹

Nutrition

Source: USDA FoodData Central.¹²¹³ Thyme is richer in iron and calcium, rosemary in vitamin C and fiber. Neither is a clear winner. At seasoning amounts, here’s our math against the FDA’s 18 mg Daily Value for iron:¹⁴ a teaspoon of dried thyme gives you about 1.2 mg of iron (7% DV), and a teaspoon of dried rosemary about 0.35 mg (2%). Nothing else either herb provides in a teaspoon is worth counting.

Can one stand in for the other?

One direction works much better than the other.

• Thyme in place of rosemary (Attributed). The Spice House calls thyme the closest all-purpose swap and says to use fresh thyme in the same amount as fresh rosemary.¹⁵ A Couple Cooks agrees on equal parts, fresh or dried, in cooked dishes, while noting that thyme is much milder.⁶ The dish will taste of thyme, not rosemary. See rosemary substitutes.
• Rosemary in place of thyme. The Spice House lists rosemary among its thyme substitutes.¹⁶ Rosemary is the stronger herb,¹ so start with half the thyme amount, finely chopped, and add more after tasting. See thyme substitutes.
• Fresh and dried. For either herb, ATK’s tests found 1 part dried to 3 parts fresh came closest to equal flavor (Computed, a general rule for herbs).⁸ See dried rosemary vs. fresh and fresh thyme vs. dried.

Safety

Both herbs are on the European Medicines Agency’s list of plants containing thujone in variable amounts.¹⁷ That’s about herbal medicines, and it gives no figure for either culinary herb. We make no claim that either herb treats or prevents any condition.

What isn’t known

• We found no source for a thyme blend with tarragon or savory as a rosemary replacement.
• Rosemary’s lemon note, which comes up a lot, isn’t explained by any compound in the sources we reviewed.

Related

• Profiles: rosemary, thyme, sage, lemon thyme
• Substitutes: rosemary substitutes, thyme substitutes
• Comparisons: rosemary vs. sage, tarragon vs. rosemary, tarragon vs. thyme, oregano vs. thyme, thyme vs. lemon thyme
• Poultry seasoning, herbes de Provence, thyme uses, rosemary uses, too much rosemary?, too much thyme?