Green Thai Chiles (phrik khii nuu)—the fresh, unripe version of a finger-sized variety that we call bird’s-eye, or bird, chiles—give green curry its name. Floral and sharp-tasting, they are also super hot. For milder curry, remove their capsaicin-rich seeds and ribs. Green Thai chiles, $4 for a 2-oz. package; templeofthai.com

Shrimp paste (kapi), made from tiny salted, fermented, and sun-dried crustaceans, adds a distinctive pungency to curries. Look for Thai brands, like Trachang, which are more moist and aromatic than those from other countries. Trachang shrimp paste, $6.49 for 3-oz. container; amazon.com

Palm Sugar (naam taan pip), derived from palm tree sap, adds a nutty, slightly fermented-tasting sweetness to curries. It’s sold in hard cakes, so chef Ricker advises throwing it into the microwave for 30 seconds to soften it before grating. Palm sugar, $8 for a 1-lb. bag; kalustyans.com

A.K.A. laos, lengkuas

Tamarind (makham), a podlike fruit with more pucker than sweetness, gives some sour curries their tartness. It’s sold in blocks of sticky pulp that you soften in hot water before using, or as a smooth, ready-to-use concentrate (shown) made from the strained juice. Caravelle tamarind concentrate, $4 for 12-oz. jar; easythaieasygo.com

Krachai, a rod-shaped rhizome, can mainly be found frozen in the U.S., where you might also see it called Chinese ginger, Chinese keys, or finger root. It adds peppery and gingery notes to curries. Krachai, $7 for 1 bunch; greenharvest.com.au

Shallots get added to curry pastes raw or grilled just until soft and fragrant. Seek out red shallots (hom daeng), the variety used in Thailand; they’re smaller and sweeter, with a more concentrated flavor than the ones we normally cook with in the States.