Making a curry paste from scratch, step by step

A homemade curry paste is a ground mixture of spices, fresh or dried aromatics and a little moisture, cooked in oil until it smells deep and savory before any other ingredient goes into the pan. The method is similar across most curry traditions: choose the base, toast and grind the dry ingredients, pound or blend the fresh ones, then cook the combined paste. Each step shapes the final flavor, and most disappointing pastes come from rushing one of them.

The whole process takes 30 to 60 minutes once the ingredients are ready, and longer with a mortar, since pounding by hand takes more time than blending. A single batch covers several meals, so it is worth making enough to store, rather than a spoonful for one dish.

Choosing the base

Decide which paste you want before you buy anything, since the ingredients differ sharply. Thai-style green paste leans on fresh green chilies, while red paste is built on dried red chilies. Both usually add lemongrass, galangal, shallot, garlic and coriander root, often with a small amount of shrimp paste and few other dry spices. Indian-style masalas usually start with ground coriander, cumin, turmeric and dried chili, and add ginger and garlic. A paste built for one style will taste out of place in the other.

Shrimp paste is made from shellfish, so leave it out if guests have a shellfish allergy, and skip it entirely when you are making a vegetarian paste.

For a concrete starting point, one batch of Thai-style red paste can use these amounts:

• 6 dried red chilies, with seeds and pale membranes removed for a milder paste
• 3 shallots
• 4 garlic cloves
• 2 lemongrass stalks, pale lower parts only
• 1 piece galangal about the size of a thumb
• 1 tablespoon chopped coriander root or stems
• 1 teaspoon each of coriander seeds and cumin seeds
• 1 teaspoon shrimp paste, omitted for a vegetarian version
• 1/2 teaspoon salt, added while pounding

This makes roughly half a cup of paste. Plan on two to three tablespoons per 13.5 to 14 ounce can of coconut milk, so one batch covers about three cans, and use a little more for a hotter curry.

Toasting and grinding the dry spices

Toast whole spices in a dry pan over medium heat, shaking the pan often, until they smell fragrant and turn a shade darker. This usually takes a few minutes. Cumin, coriander and peppercorns burn quickly, so pull them from the pan as soon as the aroma changes and tip them onto a plate to cool. Scorched spices taste bitter, and adding more of everything else will not fix that, so start the batch again.

For a Thai-style red paste, soak dried red chilies in hot water for 10 to 20 minutes until they soften, then drain them well. For a milder paste, remove both the seeds and the pale membranes, since most of the heat sits in the membranes that hold the seeds. Wrap shrimp paste in foil and toast it briefly in a dry pan, which softens its raw edge and deepens its aroma. Grind the cooled spices in a dedicated spice grinder or a mortar, taking them to the texture the recipe calls for. A grinder gives a fine powder, while a mortar leaves some texture. Wipe out the grinder between spices so the flavors stay clean.

Pounding or blending the fresh aromatics

Slice the fresh ingredients thinly and remove any tough outer layers. Lemongrass is most useful from the pale lower stalk, so trim away the fibrous outside and slice the tender center finely. In a mortar, pound the harder ingredients first, such as galangal and coriander root, with a pinch of salt. The salt acts as an abrasive and speeds the breakdown of fibers. Add shallot, garlic and chilies next, then the ground spices.

A blender works too, but it needs a little oil or water to keep the blades moving. Blend in short bursts and scrape the sides between them, since a long run warms the mixture and dulls the fresh aromas. The finished paste should look smooth, with no stringy strands of lemongrass.

Cooking the paste until it deepens

Heat a few tablespoons of neutral oil in a pan over medium heat, add the paste and stir often. It will sputter at first, then start to smell toasty and sweet. Cook it for about five to ten minutes, until the color darkens and the oil begins to separate at the edges. That separation is the signal that the raw edge has cooked away. If the paste sticks or dries out, add a splash of water and keep stirring.

Skipping this step leaves a paste that tastes green and harsh once it reaches a curry. Cooking also blends the spices and aromatics into one flavor, so the finished dish tastes rounded rather than like a list of ingredients.

Balancing salt and storing the paste

Taste a small amount once the paste has cooked, but remember that it will be diluted in the dish, so season it lightly. Thai pastes usually need little extra salt because of the shrimp paste, while a masala may need more salt added with the other ingredients. Chili heat is easy to add later and hard to remove, so start with a mild paste and adjust the heat in the finished dish.

Let the paste cool completely before storing it. Pack it into a clean, dry, airtight jar and smooth a thin layer of oil over the top to limit contact with air. Keep it in the refrigerator and use it within about a week. To keep it longer, press spoonfuls into an ice cube tray, freeze them, and move the cubes to a sealed bag. Frozen portions go straight into hot oil. Use a clean spoon each time you open the jar, because a used spoon brings bacteria that speed up spoilage.

Once you have a batch, treat it as the start of a dish rather than a finished flavor. Simmer a spoonful in coconut milk with chicken or tofu and vegetables, then finish with fish sauce or palm sugar and a squeeze of lime. Taste at the end and adjust, since the balance depends on the coconut milk and the chilies in your paste.