Coriander vs. Cilantro: One Plant, Two Ingredients, Two Chemistries

Same plant, two ingredients that can’t stand in for each other. Cilantro is the fresh leaf of Coriandrum sativum. Coriander, in American usage, is the dried fruit sold as “seed”. As the fruit ripens, the sharp aldehydes that dominate the leaf disappear from its oil, its smell changes notably, and linalool takes over in the ripe seed oil.¹ That’s why one tastes bright and green (and to some people, soapy) and the other warm and mild.

What the names mean

In dictionary terms, “cilantro” is North American English for the leaves of the coriander plant, and “coriander” is a plant whose leaves are used as an herb and whose seeds are used as a spice. So in the US, “cilantro” means the leaf and “coriander” usually means the seed. Where people don’t say “cilantro,” “coriander” can mean either part, so check whether a recipe wants leaf or seed before you shop.

“Cilantro” is the Spanish word. It came into English by 1907 from Spanish cilantro, a variant of culantro, from Latin coriandrum.² (Culantro is now also the common name of a different plant; see culantro vs. cilantro.)

Side by side

The oil figures for both parts come from the same PROSEA entry, but they’re measured differently (milligrams per gram of fresh leaf against a percentage of dry seed). Read them as a description of each part, not a ratio between them.

Why they taste so different

PROSEA puts the volatile oil of the fresh leaf at about 4 mg per gram and says aldehydes make up more than 80% of it, with (E)-2-dodecenal, (E)-2-tetradecenal and (E)-2-decenal the biggest components.¹ Eriksson and colleagues describe those (E)-2-alkenals as soapy, fatty, “like cilantro” or pungent.⁵

During ripening, PROSEA says, those aldehydes disappear from the oil and the smell of the fruit changes notably. The main component of the ripe seed oil is always linalool, usually more than 60%,¹ and a 2023 review puts it at 60 to 80%.³

The soapy taste is a leaf problem

In a 2012 genetic study of 14,604 people of European ancestry, Eriksson and colleagues linked reports that cilantro tastes soapy to a variant near a cluster of smell-receptor genes. One of those genes, OR6A2, codes for a receptor that binds several of cilantro’s aldehydes. The genetic effect was small: common variants explained only about 0.087 of the heritability of the soapy-taste trait.⁵ Since the aldehydes disappear as the fruit ripens,¹ the study’s findings are about the leaf. We found no study asking whether people who taste soap in cilantro also dislike coriander seed.

How each one is used

Cilantro. The young leaves are widely used in Latin American, Indian and Chinese dishes. Cilantro goes into Mexican salsas and meat dishes, and Arabic cooking uses both the leaves and the seeds in pickles, curries and chutneys. In China and Thailand, the aromatic taproots are eaten as a vegetable. It gets folded into guacamole and scattered over tacos and curries at the end.

Coriander. PROSEA describes the seed as a spice in a large number of dishes and an ingredient of curry powder, which can contain up to 40% coriander,¹ and USDA’s purchasing specification for curry powder lists coriander among its ingredients.⁶ It also goes into cookies and other baked goods, soups, casseroles and sausages, and in England the seeds flavor liqueurs. Coriander is also a signature spice of Belgian witbier. Clemson Extension traces the style to Flanders and says the coriander brings the orange and citrus aromas, alongside bitter orange peel.⁷

Nutrition: what a realistic serving supplies

Both get credited with impressive nutrient numbers. The numbers are real per 100 grams, but nobody eats 100 grams of either.

By our math, using USDA’s per-100 g values (cilantro: vitamin K 310 µg, vitamin A 337 µg, vitamin C 27.0 mg, fiber 2.8 g; coriander seed: fiber 41.9 g, vitamin C 21.0 mg) and USDA’s own portion weights, against FDA Daily Values of 120 µg vitamin K, 900 µg vitamin A, 90 mg vitamin C and 28 g fiber.⁸⁹¹⁰ Cilantro only becomes a real vitamin K source by the big handful. We’re not claiming either one treats or prevents any condition.

Can one stand in for the other?

No. The Spice House says fresh cilantro and dried coriander seeds have very different flavors and aren’t interchangeable,¹¹ and the chemistry above shows why. What to use instead depends on which one you’re missing:

• Out of coriander seed: see coriander substitutes. Ground cumin and caraway are the attributed swaps there. If you have whole seed and the recipe calls for ground, Ratio (Computed): McCormick’s conversion is 1 teaspoon of seed to 1 1/4 teaspoons ground, a volume figure.¹²
• Out of cilantro, or you taste soap: see cilantro substitutes, which covers culantro, flat-leaf parsley and Thai basil.
• Dried forms: see dried vs. fresh coriander and dried vs. fresh cilantro.

Safety

The FDA links recurring US outbreaks of cyclosporiasis in 2012 through 2015 to fresh cilantro from the state of Puebla, Mexico. Under Import Alert 24-23, it can detain fresh cilantro from Puebla offered for entry between April 1 and August 31 each year, unless it comes from a firm on its “Green List”.¹³ The alert covers fresh cilantro, not dried coriander seed.

What isn’t known

• We found no study comparing how people who dislike cilantro react to coriander seed.
• USDA’s coriander seed record lists no vitamin K value, so the two can’t be compared on that nutrient.
• Widely repeated uses of coriander seed in Danish pastries, butter cookies, posole, enchiladas and barbecue rubs couldn’t be traced to a source.
• No source we found explains how “cilantro” came to dominate American usage.

Related

• Coriander, cooking with coriander, how to store coriander, too much coriander
• Cilantro, cooking with cilantro, how to store cilantro, too much cilantro
• Coriander vs. cumin, coriander vs. parsley, cilantro vs. parsley