Fingerroot (Krachai): The Finger-Shaped Rhizome Behind Thai Fish Curries

Fingerroot is the flavor that identifies khanom chin nam ya, the southern Thai fish curry over rice noodles, and it tastes strong and distinctly medicinal. In Thailand it’s krachai. Botanically it’s Boesenbergia rotunda, a ginger-family plant whose small central rhizome sprouts a bunch of fleshy, finger-like roots, shaped “like Chinese keys” in one reference’s words. Cookbooks often confuse it with lesser galangal, and it isn’t interchangeable with ginger or galangal either.

At a glance

What fingerroot is

PROSEA describes the rhizome as a set of more or less globe-shaped joints at the base of the leafy shoots, with tuberous, fleshy roots shaped “like Chinese keys,” which is also its English name in that reference.² Those roots are the part most cooks know. Katzer thinks “fingerroot” is the best English name anyone could come up with, and points out that the Indonesian name temu kunci contains kunci, “key,” which also refers to the rhizome’s shape.³

Its names by region: in Thailand, krachai in general, ka-aen in the north and wan-phraathit in Bangkok; in Malaysia and Indonesia, temu kunci. Katzer gives the Khmer name as khchiey. You’ll also see “Chinese ginger,” but we found no reference that uses it.

Not lesser galangal

Fingerroot and lesser galangal (Kaempferia galanga, sold as kencur and sometimes called sand ginger) are easy to mix up. Katzer says cookbooks often confuse the two, and that the name kencur often gets misapplied to fingerroot.³ Neither one is galangal, which is Alpinia galanga.

Where it comes from

The references disagree on where fingerroot is native:

We go with Kew as the botanical authority. Kew’s list includes the Andaman Islands but not the Nicobars, so we couldn’t confirm a much-repeated story about fingerroot and the Nicobarese from it, and we found no other source for it.

PROSEA says no production statistics are available. It gives an average yield of about 10–30 tonnes of fresh rhizomes and roots per hectare, four to six months after planting.²

Flavor and aroma

Katzer calls fingerroot’s flavor strong and dominating and, for want of a better word, “medical.” He finds the dried rhizome stronger and more medical still.³ Think earthy and camphor-like, with a peppery warmth and less brightness than ginger.

The compounds

Beyond the oil, fingerroot contains some unusual chalcones and flavonoids. PROSEA mentions dihydrochalcone derivatives like boesenbergin A and compounds related to panduratin A.² A 2025 review covers panduratin A, pinostrobin, pinocembrin and cardamonin among roughly 205 identified metabolites.⁴

Compared with galangal

Galangal tastes strong and pungent, like a mix of pepper and ginger. No source we found compares the two directly. Fingerroot is earthier and more medicinal, galangal sharper and more piney, and neither one substitutes well for the other. See also galangal vs. ginger and galangal substitutes.

How fingerroot is used

Thailand is where fingerroot matters most. Katzer says Thai cooking is the only cuisine where it’s an important flavoring. It often goes into curries, especially fish curries, and it’s a common ingredient in vegetable stews and fish soups, often with kaffir lime leaves.³ In Thailand it’s also a key condiment in shrimp soup and a common seasoning for fish, vegetables and curry.⁴

The signature dish is khanom chin nam ya, rice noodles with a fish curry sauce. Thailand Foundation’s recipe uses a cup of chopped fingerroot with snakehead fish, salted mackerel and shrimp paste,⁵ and Pailin Chongchitnant calls fingerroot the flavor that identifies the dish.⁶ See Thai spices and curry paste vs. curry powder.

Indonesia and elsewhere. The sources disagree on how much Indonesians cook with fingerroot. PROSEA says the rhizomes and roots are commonly used in cooking throughout Java and most of Indonesia,² while Katzer calls it a rare spice in Vietnamese and Indonesian cooking.³ In China, Katzer says, it’s a medicine, not a cooking spice. We couldn’t trace claims about its role in Cambodian kroeung paste and Thai tempeh cake.

Traditional medicine. PROSEA records it as an ingredient in post-partum tonic mixtures and as a stomachic and carminative.² Those are traditional uses, not tested effects.

Buying and storage

• Fresh. Katzer says Thai food stores often carry fingerroot, and its shape makes it easy to spot. In Thailand the fresh rhizome is almost always available.
• Frozen. Chongchitnant says fresh fingerroot freezes very well.⁶
• In brine. You can also find it in brine in glass jars at Asian grocery stores.
• Dried. Katzer suggests soaking dried fingerroot in warm water and grinding it to a paste.

We found no published shelf-life figure for fresh or frozen fingerroot.

Health and safety

A 2025 review in Frontiers in Pharmacology sums up the research on fingerroot’s effects. It says most of that research has focused on antibacterial effects in vitro (in the lab), and that research on its antioxidant effects is limited, especially in living organisms.⁴ It also says the plant’s adverse reactions remain undetermined.⁴

Claims that fingerroot treats ulcers, cancer or sexual dysfunction go well beyond that evidence. Lab results don’t show that eating fingerroot treats or prevents any disease, and we make no such claim. We couldn’t trace claims about its mineral content.

Substitutes

Nothing comes close. Chongchitnant suggests either leaving it out of nam ya or using more galangal, though she notes the dish won’t taste quite right without it.⁶ Fingerroot’s flavor is strong, so start small and adjust to taste. See galangal, ginger, sand ginger, sand ginger substitutes, turmeric and lemongrass.