Thai Tom Yum Noodle Soup

What is Tom Yum?

Tom Yum (sometimes spelled Tom Yam) is arguably the most popular Thai hot and sour soup. The most known version of this soup, Tom Yum Goong, is made using shrimp or prawns.

Other well-known versions of this dish include Tom Yum Pla (fish), Tom Yum Gai (chicken), and Tom Kha Gai (chicken, galangal, and coconut milk).

Is Tom Yum a clear soup or a creamy soup?

Tom Yum is prepared and enjoyed both ways. The clear version is called Tom Yum Nam Sai. The creamy soup with coconut milk or evaporated milk is referred to as Tom Yum Nam Khon.

Ingredient Notes

Here are some useful notes on the ingredients you need to make this delicious Tom Yum Noodle Soup.

Nam Prik Pao (Thai Chili Paste)

Nam Prik Pao is a classic Thai chili paste/jam and a key ingredient in the modern version of Tom Yum. The paste is a pantry staple in Thai cuisine and is used as a condiment, dip, and flavor enhancer in Thai recipes.

The Nam Prik Pao jars sold in Asian grocery stores are often labeled “chili paste” or “chili paste in/with oil”. Be sure to read the ingredients, so you don't confuse it with other kinds of Asian chili pastes (like Chinese and Korean ones).

Since Nam Prik Pao is traditionally made using roasted chilies, shallots/onion, garlic, tamarind, fish sauce, sugar, and dried shrimp or shrimp paste, you want to look for these (or similar) ingredients on the label. If the product is made in Thailand, that's an added layer of assurance that you’re grabbing the right kind of chili paste.

Nam Prik Pao is umami, sweet, spicy, and tangy all at the same time and cannot easily be substituted. If you can't find this paste, your best bet is to make it at home. Here is a good recipe for Nam Prik Pao.

Once opened, the jar/bottle of Nam Prik Pao should be stored in the refrigerator.

Tom Yum Paste

I highly recommend using a store-bought tom yum paste for a proper boost of flavors. This is usually marketed as a paste for “instant tom yum” but I use it along with all the fresh aromatics for tom yum. It's almost always stocked in Asian grocery stores. You may also be able to find it in the international aisle of your local grocery store. And any tom yum paste will do. As long as it's made in Thailand.

Tom yum paste stays good in the refrigerator after opening. You can also freeze it if you like. Put 1 tablespoon of tom yum paste in each cube of an ice cube tray and freeze overnight. Empty the frozen cubes from the tray in a freezer-safe zip-top bag the next day, label the bag, and freeze again.

Fish Sauce

Fish sauce is a liquid condiment made from fermented fish. Now, this initial piece of information may put you off, and you may be correct in assuming that it has a pungent flavor, but it is incredibly popular in many East Asian Cuisines for a reason. Sure it smells and tastes strong on its own, but in the right amount, it adds a lovely umami flavor to the food.

Fish sauce can be stored in the pantry, but storing it in the refrigerator will extend its freshness for longer durations.

When buying fish sauce, be sure to look at the ingredients. A good fish sauce should have just a few ingredients like fish/anchovy extract, salt, sugar, and water. The longer the list, the more diluted and low-quality the fish sauce will potentially be. I prefer using the Squid Brand fish sauce that's made in Thailand.

Kaffir Lime Leaves

These are leaves of the kaffir lime or makrut lime plant and are easily available in Southeast Asian grocery stores around the world. Some stores carry frozen whole leaves, which work just as well for this recipe.

You may also find dried leaves in some stores, but they are not nearly as fragrant and potent as fresh leaves.

To store any leftover fresh leaves, stack 12-14 leaves on top of each other and pack them in a small piece of food-safe cling/plastic wrap, leaving no air pockets. In the same way, make more of these single-use small packets using all the leaves you have. Put these leaf packets in a zip-top bag and freeze them for up to 3 months.

Lemongrass

Lemongrass is the aromatic stalk of a tropical grass and is widely used in East Asian cuisines. It is usually available fresh and/or frozen at Asian grocery stores. You may also find finely chopped lemongrass in the freezer section of the store but that is not suitable for making Tom Yum.

Lemongrass is hard and inedible and its chunks are sometimes removed from the food during the cooking process (after it has simmered/boiled for an adequate amount of time in the soup/base).

You can also leave the lemongrass chunks in, as is done traditionally, but warn your guests that the lemongrass pieces are inedible.

If you don't use lemongrass frequently, freeze the leftover stalks for later use. Start by cutting off the small (bulb) end on the yellow/pale side of the stalk. Then peel away the outer, tough layer of the entire stalk. Now chop off and discard the green/woody part of the stalk. Cut the yellow/white part of the stalk into 2 to 3-inch chunks. Wrap these chunks in a piece of aluminum foil before storing them in a zip-top freezer bag. Lemongrass stored this way can remain good for up to 3 months in the freezer.

Galangal

Although galangal root looks very similar to ginger, they both taste very different and cannot be used interchangeably.

Galangal can also be found in Asian grocery stores. If you don't find fresh galangal, look for frozen chunks. Galangal powder does not work in this recipe.

If you have leftover fresh galangal, you can freeze it for up to 3 months. Peel and slice the galangal. Then grab single-use portions of galangal slices and wrap them in food-safe cling/plastic wrap. Store these wrapped packets in a freezer-safe zip-top bag.

Tomatoes

Any type of commonly available red tomato will work for this recipe. Cherry tomatoes, cut in halves, can also be used.

Noodles

Check out the FAQs section on this page for the note on noodles.

Chicken Broth/Stock

Chicken broth/stock will add depth of flavor to this soup. If you don't have or cannot find unsalted broth/stock, you can use salted chicken broth/stock or chicken bouillon.

To substitute 1 cup (250 milliliters) of broth/stock, dissolve 1 teaspoon of chicken bullion powder or 1 chicken bouillon cube in 1 cup (250 milliliters) of hot water.

When using salted chicken broth/stock or bouillon powder/cubes, skip the salt mentioned in the recipe. Also, reduce the quantity of fish sauce in this recipe from 4 tablespoons to 3 tablespoons. Check the saltiness of the soup towards the end of the cooking and adjust the fish sauce and the salt if you feel the need.

Shrimp/Prawns

Shrimp and prawns can be used interchangeably in this recipe. I prefer large shrimp but medium ones will work too. Small shrimp and prawns will shrink to a very small size as they cook.

I find it convenient and easier to use shelled and deveined frozen shrimp (tail on or tail off – both work) available at my local Costco.

Traditionally, shrimp/prawn shells and heads are boiled in water to make shrimp broth for the tom yum soup, but because I use frozen shrimp, I substitute chicken broth/stock for the shrimp broth (as mentioned in the recipe) to add some richness to the soup.

When using frozen shrimp, let them thaw completely to ensure even cooking.

Shallots or Onions

You can substitute 1 medium onion for the 3 medium-sized shallots required in this recipe.

To make shallot wedges for the soup, first cut a shallot into half, lengthwise, from bulb to tip. Chop off the small bulb end from both halves and remove the peel. Now place the shallot half, flat side down, on a cutting board, and cut into 2 pieces lengthwise.

When using onions, cut each half into 3 or 4 pieces, depending on the size of the onion, and the wedge thickness you prefer.

Mushrooms

In Thailand, straw mushrooms are commonly used for tom yum soup, but you can use any fresh mushroom type you can find.

I prefer to use Asian varieties like shimeji, oyster, and enoki mushrooms.

Canned mushrooms can work too, but try to get fresh ones for the best flavor and texture.

Canned Evaporated Milk or Coconut Milk

You will need either of these to make the creamy version of tom yum. Being lactose intolerant, I tend to lean more towards coconut milk, whenever I can. Coconut milk also gives more depth to the overall flavor of Tom Yum. However, restaurants usually use evaporated milk.

You will need canned coconut milk for this recipe, not the super diluted coconut milk sold in cartons that are often branded as a coconut blend or coconut beverage.

When shopping for coconut milk, always check the ingredients on the can. Some brands have artificial flavors and other additives on their ingredient list. The fewer the ingredients, the better. Also, look for a higher percentage/concentration of coconut milk. The higher the percentage, the more it will taste like freshly prepared coconut milk.

Thai Chilies

You can use red chilies or green ones, or both. Thai chilies are often easy to find. But if you don't have easy access to them or you don't use them frequently, consider freezing whole/uncut leftover chilies in zip-top freezer bags for later use.

Tips for Recipe Success

1. Add the lime juice when all the cooking is done. Wait for 2 to 3 minutes after you turn the heat off. Lime juice tends to lose potency/flavor at high temperatures and may turn the soup slightly bitter if added to the boiling soup. Adding the lime juice while cooking might also curdle the soup. So it’s best to wait and add the juice later.
2. Add the noodles to the soup just before eating. If left in the soup for a long time, noodles will continue to soak the liquid and turn mushy and unpleasant. Serving the noodles and soup separately will allow easy customization (I like more soup and a little portion of noodles) and will also make it easier for you to store the soup separately from the noodles if you have any leftovers.
3. If available, use unsalted chicken broth/stock. If your broth/stock is salted, skip the salt and reduce the quantity of fish sauce from 3 tablespoons to 2.5 tablespoons. Adjust the salt and the fish sauce towards the end of the cooking process as needed. Avoid using beef stock as a substitute as it will make the soup taste very different.
4. Adjust the soup to your liking. If it's too tangy for you, add some more sugar. If you want it spicier, add some more chopped Thai chilies. If you like it tangier, add more lime juice.

Scaling the Recipe

Scaling up a recipe is not always an exact science. Spicy ingredients can sometimes increase the heat of a dish disproportionately. And that can be the case with the taste/smell of some aromatics too. For example, 2x (double the quantity) of a spicy ingredient might be 3x (3 times) spicier.

When scaling up, increase the quantity of the spicy ingredients (for example Thai/Bird’s eye chili in this case) by half for each additional portion. This will prevent the spiciness from overpowering the dish. You can always increase the quantity if you feel the dish isn't spicy enough.

Making Ahead

This soup tastes great the next day as the flavors have more time to work their magic together. While you can finish making the complete soup (without the noodles) and refrigerate/freeze it, I strongly recommend that you don't cook the shrimp in advance.

When reheating the soup, turn the heat to medium-high, bring the soup to a rolling boil, and then add the thawed, room-temperature raw shrimp. Cook the shrimp for 1 to 2 minutes, or until they turn opaque and white/pink. Taste the soup and adjust the lime juice, fish sauce, and/or Thai chili paste to adjust the sourness, saltiness, or heat as per your liking. You can also add more chopped Thai chilies if you like your soup spicy. Also, boil the noodles fresh just before serving.

You can make and freeze this soup without shrimp and noodles several days in advance. Check the freezing tips under the storage section below.

Storage

• Let the leftover soup cool to room temperature and refrigerate the soup separately from the noodles in an airtight container for up to 2 days or in the freezer for up to 3 months.
• If it's difficult to find ingredients like kaffir lime leaves, lemongrass, and galangal, you can freeze these ingredients as explained in the ingredients section above. Or you can make and freeze a big batch of the soup (without the shrimp and noodles).
• Freeze individual portions of the soup in zip-top freezer bags. Don’t fill the bags to the top, as liquids expand when they freeze. Stack these soup bags on top of each other on a flat surface, like a sheet pan, for easier storage. Freezing the soup will help preserve all the amazing flavor.
• Avoid freezing the soup with shrimp or noodles in it. For best results, cook shrimp in the boiling soup at the time of reheating. Also, make the noodles fresh before serving. Cooked noodles don't freeze and thaw very well and can turn mushy when reheated.
• Always label the food with its name and preparation date before freezing.

Reheating

Refrigerated or Room Temperature Soup

• Soups don’t heat up very well in microwaves as the heat doesn't always get distributed evenly, especially when reheating bigger quantities. Reheat on a cooktop if you can.
• If you must use a microwave, make sure to use a microwave-safe container. Set the timer to 1 minute the first time and then heat in additional intervals of 30 seconds, as needed.
• Pause the microwave and stir the soup a few times to ensure even heating and prevent splatters.

Frozen Soup

• If you have time, defrost the soup in the refrigerator. It may take between 24 and 48 hours to completely thaw, depending on the size and shape of the storage bag or container and the temperature inside your refrigerator.
• Avoid using the microwave for thawing frozen soup, as the plastic from the bag or the container may leech into the food.
• If you want to defrost faster, place the soup bag/container in another container filled with room-temperature water. Replace the water every 30 minutes until the soup has completely thawed. Then reheat on the stovetop.

Variations

• You can use any of your favorite noodle types for this recipe.
• Turn this recipe into Tom Yum Rice Soup by adding sticky rice or steamed rice instead of noodles.
• Try this recipe with thin slices of boneless chicken if you want to skip the shrimp/prawns (see the FAQs).
• If you like your tom yum tangier, add more lime juice. If you like it sweeter, add some sugar. If you want it more creamy, add more coconut/evaporated milk. To increase the spice level, add more chopped chilies or Thai chili paste.