Kaffir lime (makrut).

Makrut is easy to tell apart from an ordinary lime. The skin is dark green, thick and covered in bumps and wrinkles, and when you scratch it the smell is sharp, floral and very strong. Inside there's not much juice, and what there is tastes sour with a bitter edge. The real prize is the zest. A small amount goes a long way in Thai curry pastes, where it gives that bright, perfumed note you can't get from anything else.

Ways to use it

• Grate or finely chop the outer green zest into red curry, green curry or chu chee paste. Leave the white pith behind, it's bitter.
• Pound a little zest into the paste for tod man pla, the Thai fish cakes.
• Squeeze a few drops of juice into a nam prik or a sour soup, tasting as you go.
• Halve a used lime and drop it into a pot of tom yum or a clear broth for scent.

Storing it

Keep the limes dry, in a cool place or in the fridge's vegetable drawer, and use them while the skin is still firm and glossy. Scrub them under running water before grating, because the zest is the part you eat. If you won't use a whole lime at once, grate the zest you don't need and freeze it in a small, tightly closed container.

Where it comes from

Grown to certified organic standards. The certificate for each lot is shown when you trace your pack.

Every pack will carry a lot code. Enter it on the Trace your pack page and you will see the farms in that lot, the harvest date and the certificate.