Cooking Thai Food Outside Thailand: Substitutes and Shopping

Thai food is cooked all over the world, often a long way from a Thai market. Most home cooks outside Thailand face the same question sooner or later: the recipe asks for something you cannot find, so what do you use instead?

Some substitutions work well and nobody at the table will notice. Others change the dish so much that it becomes something else. Knowing which is which is more useful than any list of exact replacements, and it means you can cook confidently with what is in front of you.

Swaps that work

Several common ingredients have close equivalents that are easy to find:

Palm sugar: light brown sugar, or a mix of white and brown, is a fair stand-in. Avoid very dark sugars with a strong molasses flavour.
Limes: Thai limes are smaller and more fragrant, but the limes sold in most supermarkets work well. Use a little more if they are mild.
Shallots: Thai shallots are small, red and sharp. Banana or round shallots are fine, and red onion works in salads.
Thai aubergines: the small round green ones are hard to find. Ordinary aubergine, cut into chunks, works in green curry, though it cooks faster and softens more.
Coriander root: if your coriander comes without roots, use a larger amount of the lower stems. They are milder but similar in character.
Fish sauce: Thai and Vietnamese fish sauces are close cousins and can be used interchangeably. Choose one with a short ingredients list.
Shrimp paste: Malaysian belacan, sold in firm blocks, can replace Thai kapi in curry pastes and chilli dips. It is drier, so it may need mashing with a drop of water.

Swaps that do not work

Some ingredients carry a flavour that nothing else can replace. In these cases it is better to find the real thing, or to cook a different dish.

Galangal is the clearest example. It looks like ginger, but it tastes sharp, piney and citrusy rather than warm and sweet. Ginger in tom kha gives you a pleasant soup that is not tom kha. In a curry paste where galangal is one of many ingredients the difference is smaller, but it is still there. Ground dried galangal is a poor substitute; dried slices are better and can work in soups.

Makrut lime leaves have an intense, floral citrus scent with no real equivalent. Lime zest gives some of the citrus but none of the distinctive perfume. The zest of the makrut lime fruit itself is used in curry pastes, and it is even harder to find than the leaves, though ordinary lime zest is a reasonable compromise there.

Basil is where many recipes go wrong. Thai cooking uses several basils, and they are not interchangeable:

Holy basil (kra pao): peppery and clove-like, with slightly fuzzy leaves. Essential for pad kra pao.
Thai basil (horapa): purple stems and a sweet anise flavour. Used in green curry, red curry and many stir-fries.
Lemon basil (maenglak): lemony, used in some soups, curries and, as seeds, in desserts.

Thai basil is much easier to find than holy basil. Stir-fried meat with Thai basil is a good dish, but it is not pad kra pao. Italian sweet basil is a poor stand-in for either.

Coconut milk needs care too. Use canned or cartoned coconut milk sold for cooking, not the diluted coconut drinks sold alongside dairy alternatives, which are too thin and often sweetened. Light coconut milk is simply diluted, so it will not fry curry paste properly.

Fresh, frozen, dried or in a jar

Many Thai aromatics are sold in more than one form. A rough order of preference helps when deciding what to buy:

Fresh is best for everything, when it is in good condition.
Frozen is very good for lemongrass, galangal, makrut lime leaves and chillies. Their flavour holds up well, and they work straight from the freezer in soups and pastes.
Jarred pastes of lemongrass or galangal are acceptable shortcuts in curries and marinades, though they can taste flat or slightly sour from preservatives.
Dried lemongrass, galangal and lime leaves are a last resort. They can flavour a simmering soup but add little to a paste or salad.

Freezing herbs and pastes

If you find a good supply of fresh aromatics, buy extra and freeze them. Trim lemongrass and cut it into lengths, slice galangal before freezing since it is hard to cut later, and freeze makrut leaves flat in a sealed bag. Chillies freeze whole.

Curry paste freezes well. Pound or blend a large batch, divide it into small portions in an ice cube tray, then move the frozen cubes into a labelled bag. Leafy herbs are different: holy basil, Thai basil, mint and coriander lose their texture when frozen and are best bought fresh and used within a few days. Thai basil dislikes the cold and tends to blacken in the fridge, so keep it in a glass of water at room temperature, while coriander and mint keep best wrapped in damp paper in the fridge.

Equipment: wok, pan, mortar and blender

A wok is ideal for stir-frying, but it works best over a strong gas flame. Many home hobs, especially electric and induction, heat only the base of a round wok. In that case a flat-bottomed wok or a large, heavy frying pan can do a better job. Whatever you use, heat it well before the oil goes in, and cook in small batches so the food fries rather than stews.

For curry pastes, a heavy granite mortar and pestle gives the best texture, because pounding crushes the aromatics and releases their oils. A blender or small food processor is a reasonable alternative, though it usually needs a little liquid and produces a wetter, less fragrant paste. Pounding the toughest ingredients by hand first, then finishing in the machine, is a good compromise. For som tam, a deep clay or wooden mortar with a wooden pestle is the traditional tool, since granite is too heavy for bruising papaya.

A rice cooker is not essential, but it makes jasmine rice reliable, and many Thai households would not be without one.

Shopping at an Asian grocer

Asian grocers are the best source of Thai ingredients outside Thailand, and they reward a little exploring.

Check the freezer cabinets. Galangal, lemongrass, makrut leaves, banana leaves, pandan leaves and fresh noodles are often found there when the fresh shelves are empty.
Ask when fresh herbs and vegetables arrive. Many shops receive deliveries on particular days, and that is when holy basil, Thai aubergines and fresh noodles are at their best.
Read the labels. Many products imported from Thailand carry English labelling alongside the Thai, including ingredients lists.
Buy small at first. Pastes, sauces and dried goods vary between makers, so try a small jar or packet before committing to a large one.

Above all, cook with what is good where you live. A tom yum made with fresh local prawns and frozen aromatics will taste better than one made with tired fresh ones. Thai cooks have always adapted to their markets, and doing the same is in keeping with how the food is meant to be cooked.