Making Thai Curry Paste from Scratch: Red, Green and Massaman

Every Thai curry starts with a paste. Before any coconut milk, meat or vegetables go into the pot, a cook pounds chillies, aromatics and seasonings into a thick, fragrant mass, then fries it until it smells completely different from the raw ingredients. The paste is the curry. Everything else is what the curry is cooked with.

Thai cooks call these pastes khrueang gaeng, which roughly means curry ingredients. Most markets sell them freshly made, scooped from large mounds into small plastic bags, and plenty of Thai households buy them rather than making their own. But pounding a paste at home at least once is the best way to understand what a curry is made of, and a fresh paste has a brightness that is hard to match.

The shared base

Most central Thai curry pastes are built on the same core of ingredients. The differences between them come from the type of chilli and from a handful of extra spices. Learn the base and the rest is variation.

• Chillies: dried for red, yellow and massaman pastes, fresh for green.
• Shallots and garlic: for sweetness, body and depth.
• Lemongrass: only the pale lower part, finely sliced across the grain.
• Galangal: sharper and more piney than ginger, and much harder to cut.
• Makrut lime zest: just the thin green skin, not the bitter white pith below.
• Coriander root: the roots and lower stems, which carry far more flavour than the leaves.
• Shrimp paste (kapi): a small amount for savoury depth.
• Salt: as seasoning, and as an abrasive that helps break down the fibres.
• Dry spices: usually coriander seed, cumin and white peppercorns, toasted and ground.

Red, green, yellow and massaman

Red curry paste (khrueang gaeng phet) is the closest thing to a master recipe. Dried red chillies give it its colour and a deep, rounded heat, and it is used not only for red curry but also for dishes such as fish cakes and many stir-fried curries.

Green curry paste swaps dried chillies for fresh green ones, usually a mix of small bird's eye chillies for heat and larger green chillies for colour and bulk. Many cooks add extra coriander root and makrut lime zest, and sometimes a few holy basil or coriander leaves to deepen the green. Because fresh chillies are fierce, green curry is often the hottest of the family, despite its reputation as a gentle choice.

Yellow curry paste (gaeng kari) uses dried chillies again but leans on turmeric and curry powder, which give it its colour and a warmer, more Indian-style spice. It is milder than red and pairs well with chicken and potatoes.

Massaman paste goes furthest in that direction. Alongside the usual base it takes the sweet spices brought to Thailand by Muslim and Persian traders: cardamom, cinnamon, cloves and nutmeg or mace. The shallots and garlic are often dry-roasted before pounding, which gives the paste a mellow, slightly smoky sweetness.

Fresh and dried chillies

Large dried chillies are the backbone of red, yellow and massaman pastes. Snip them into pieces, shake out most of the seeds, and soak them in warm water for 10-15 minutes until soft. Removing the seeds lowers the heat and lets you use more chillies, which means more colour and more depth without making the curry unbearable. Squeeze them well before pounding, as extra water makes a wet paste that is harder to fry.

Some cooks add a few small dried chillies for extra fire. For green paste, use fresh chillies as they are, roughly chopped. Wear gloves if you are handling a large quantity, and keep your hands away from your eyes either way.

Toasting the spices

Whole dry spices are toasted before grinding. Put the coriander seed and cumin in a dry pan over a low to medium heat and shake it often until the seeds darken slightly and smell nutty, usually a minute or two. Cumin burns faster than coriander, so some cooks toast them separately. Tip them out of the hot pan straight away, let them cool, then grind them to a fine powder with the white peppercorns.

Grinding the spices on their own first matters. Whole seeds tend to bounce around in a mortar full of wet aromatics and never break down properly. For massaman paste, toast and grind the cardamom, cloves and cinnamon in the same way.

The pounding order

The rule is simple: hardest and driest first, softest and wettest last. Each ingredient is pounded until it has broken down before the next goes in.

1. Salt and the soaked dried chillies (or fresh chillies for green paste).
2. Galangal, then lemongrass, then makrut lime zest.
3. Coriander root.
4. Shallots and garlic.
5. Shrimp paste.
6. The ground dry spices, worked in at the end until evenly mixed.

A good paste is smooth enough that you cannot pick out individual pieces of lemongrass or galangal. That takes time, often 20-30 minutes for a full batch, and is the reason market pastes exist. A food processor or blender will do the job faster, though it usually needs a splash of water or oil to turn, and the result is slightly wetter and less fragrant. A useful compromise is to pound the tough fibrous ingredients first and finish in a machine.

Storing homemade paste

A batch of paste is usually more than one curry needs. Pack the rest into a clean jar, press it down to remove air pockets and pour a thin layer of oil over the top. It will keep in the fridge for about a week. For longer storage, freeze it in small portions, an ice cube tray works well, and transfer the frozen cubes to a bag. Frozen paste keeps its flavour for a few months and can go straight into a hot pan.

When bought paste is fine

There is no shame in a tub of curry paste. Thai-made pastes sold in tubs, tins and sachets are widely used in Thailand itself, and they produce a perfectly good curry on a weeknight. A few things make them taste better:

• Fry the paste properly in oil or cracked coconut cream until it is deeply fragrant and the oil turns red. Most of the difference between a flat curry and a good one happens here.
• Taste before seasoning. Bought pastes are often salty, so add fish sauce at the end, not the start.
• Freshen it up by pounding in a little fresh lemongrass, galangal, garlic or makrut lime zest.
• Finish with fresh herbs: Thai basil for green or red curry, a few torn makrut lime leaves for most others.

Make your own when you have time, or when a curry is the centre of a meal. Use bought paste the rest of the week. Once you have pounded a paste from scratch, you will also be much better at judging which tub on the shelf is worth buying.