WHAT IS TOM YUM SOUP?

This tom yum soup recipe is my favorite, which I will show you how to prepare using tom yum goong (spicy soup with shrimp) as an example.

Tom Yum soup is the most famous Thai soup in the world for a reason.  Although it looks deceptively unpretentious, it is packed with a bold, citrusy and savory flavor. You will feel the bursting taste from the fresh Thai herbs with a pop of spicy heat lingering in your mouth.

Let’ get into the details right in.

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1. Ingredients for the tom yam soup

The ingredients for this tom yum soup recipe is divided into four categories:

1. The aromatic: The trio of Thai ingredients forms the base of the tom yum flavor.  I am referring to the combination of lemongrass, galangal, and kaffir lime leaves.  You also need Thai bird’s eye chilies for the spiciness. You may also add some garlic and shallots to enhance the taste.
2. The stock: Shrimp stock (made with shrimp heads and shells) is the best for making tom yum goong (tom yum shrimp soup).  You can use chicken stock for tom yum gai (chicken tom yum soup), but it is unappetizing to use water as it lacks flavor. Store-bought chicken broth (in packets) is the next best thing but is not authentic since it is added with other ingredients targeted for western cuisine. 
3. The main ingredients: Shrimps, squid, fish, and chicken are the most common main ingredients. Mushrooms always play second fiddle but are always included. Besides that, tomato and onion are a welcome addition to the list.
4. Seasonings: The seasonings are fish sauce, sugar, lime juice, and Thai chili paste. All of them play like a symphony to produce an incredibly complex flavor when used together.

How to prepare tom yum soup

a. Get ready the ingredients in this tom yum soup recipe

Three components make up the base flavor of tom yum soup- lemongrass, kaffir lime leaves, and galangal.  This combination is also frequently used in other Thai dishes.

Lemongrass

• Cut off the green section of the lemongrass and also the part near to the root. 
• Remove the outer sheath of the center part.  The inner layer of this part is where the flavor is concentrated. It is slightly pale green, and the innermost layer is almost white.
• Cut this part on the bias into three or four sections, depending on the size. Some people like to bash them to release the flavor much faster, but I prefer to leave it for aesthetic reasons.  I can extract the flavor by boiling it slightly longer.

Kaffir lime leaves

These leaves have a unique aroma (you can smell them to check out). Plug the leaves and discard the stems.  You may want to tear them in half to speed up the flavor’s release but prefer to leave them intact and boil a little longer along with the lemongrass.

Galangal

Galangal looks like ginger but has a distinct flavor. As such, you cannot substitute galangal with regular ginger (which can be disastrous).  Galangal is quite hard and sometimes can be quite dirty (because it is a root vegetable). Wash them thoroughly and cut them into thin slices. There is no need to remove the skin for this tom yum soup recipe since we will not eat them, only to extract the flavor.  

Garlic and shallot

Garlic is optional in making tom yum soup, as you might have read some other tom yum recipes that do not include it.  However, I like the flavor of garlic, which complements lemongrass and galangal.  Bash the garlic, throw the whole clove into the stock, and boil together with other aromatic ingredients.

You can substitute the shallot with yellow onion, which is a personnel preference as I have seen various Thai restaurants adopt different approaches.  Cut the shallot into half if they are too big. 

Note:

• These ingredients are readily available in Asia but can be challenging to get at certain places outside Asia, especially galangal. The best place to find these ingredients is the Asian grocery stores near you.  Some might come in the form of a frozen state, which is Ok, although fresh ingredients are the best.
• These three items are not for eating, as they are ar hard and tasteless after boiling.  However, many cooks like to leave them in the bowl while serving, mainly for decoration purposes (and to show the tom yum is made from the real ingredients, not from the store-bought tom yum paste).  Thai people know that they are not edible, but if you have guests who never try tom yum, gently remind them not to chew on them.

b. Use shrimp stock to prepare tom yum broth

The most crucial element to making the best tom yum soup is the stock.  You can use plain water to make tom yum, but the authentic way always starts with a good stock, mainly shrimp stock.

There are two ways you can do it.

• The first method is to cook the shrimp in water with the shell and head attached. By the time the shrimp is cooked, the water has become the shrimp stock. 
• The second method is to separate the head and shell from the meat, use them to boil in water to make the stock, and then strain to get the clean stock.  I don’t like to peel each shrimp and remove the head while eating, but that is only my preference, of course.

I will wash the head and shell repeatedly as they are quite dirty sometimes. Then prepare a pot of water and bring it to a boil. Pour the shrimp heads and shells into it and keep it at a constant boil to extract the flavor. 

Do this for about fifteen minutes, and the flavor should have been all extracted.

Note: If you make tom yam goong (shrimp tom yam), try to avoid using any chicken stock as the base as it is not the best way to present the authentic flavor.  You can do so if you are preparing tom yam gai (chicken tom yum).

c. Prepare the remaining ingredients

Mushrooms

Mushrooms are essential ingredients in making tom yum soup. I haven’t been served tom yum soup in any restaurants without mushrooms, be it tom yum goong, tom yum gai, or other variants.

The common types are oyster mushrooms, which I used in this tom yum recipe.  Tear the mushroom into small pieces before adding it to the soup stock.

Other suitable mushrooms for tom yum are shiitake mushrooms, button mushrooms, straw mushrooms, and shimeiji mushrooms.

Tomato

Cut one tomato into wedges and throw them into the stock along with the mushrooms. Some tom yum soup recipe does not include tomato, but I used it to add more flavor to the soup.  

Thai chilies 

Thai chilies are a must for preparing tom yum. Bird’s eye chilies are the ideal types for making tom yum.  They are relatively small, about two to three inches long, and comes in two colors- red and green.  These chilies are fiercely hot, so be prudent if you cannot withstand the heat.  Generally, I will use three chilies for each serving, but the Thai people usually include more as they can take very hot food.

Cut off the chilies’ stem, then bash the chilies with the knife and cut them into two sections.

Lime juice

The citrusy note of tom yum soup comes from lime juice.  You should choose those larger lime (key lime), not those small kalamansi lime, as you need about a quarter cup of lime juice for two servings.

Strain the lime juice through a wire mesh strainer to remove the pulp and seeds.  

The flavor of lime juice can be destroyed by prolonged boiling, so it is best to add only at the final stage of cooking, preferably after turning off the heat.

The rind of the lime is bitter, so it is essential only to use the juice.

Evaporated milk

There are two types of tom yum, the clear and the milky one.  You need to add evaporated milk (not condensed milk or regular fresh milk)  to turn the clear soup into a milky one.  Evaporated milk is an authentic ingredient. Coconut milk is not for the creamy tom yum soup recipe.

Thai chili paste (Nam Prik Pao)

The tom yum soup flavor will accentuate by adding a small amount of the Thai chili paste.  This chili paste is different from other chili paste made in other countries as it contains some shrimp.  Other chili pastes are not the substitute for the Thai chili paste.

You need to add more Thai chili paste to the soup when preparing the creamy tom yum soup. It is added in the final stage, together with the evaporated milk.  The chili paste coupled with the evaporated milk will turn the clear soup into a red and milky color and slightly thicker.

Fish sauce, sugar, and coriander leaves

Fish sauce is the main ingredient to provide the savory flavor of tom yum soup. The saltiness should balance with a fair amount of sugar (white or brown sugar).  Sugar also acts as the balancing ingredient for the sourness of the lime juice. Therefore, it is useful to carry out a taste test before serving, as the saltiness and sourness may differ due to the use of different brands of fish sauce and the lime quality.

The leaves of the coriander are added at the last minute for decoration. The stems are cut into tiny short sections and add to the soup for more flavor.

The cooking process

a. Prepare the shrimp stock for tom yum

Clean the shrimp heads and shells thoroughly with water.  You can use all the heads and shells from the shrimp to cook this tom yum soup, but the flavor might not be enough. Therefore, I suggest you keep the shrimp heads and shells whenever you purchase shrimp and keep them for this purpose. 

Bring a pot of water, about 1.5 liters, to a boil. Place all the heads and shells into it and wait until it starts to boil again. 

Reduce the heat and keep it at a constant boil with the lid on for fifteen minutes, enough to extract all the flavor.  

Remove the heads and shells by pouring the stock through a wire mesh strainer.  The stock should now be reduced to about 1 liter, which is the right amount for this recipe.

b. Prepare other ingredients

Prepare the rest of the ingredients (cut, wash, measure) as mentioned in the previous section.

c. Extract the flavor of the spices 

Bring the shrimp stock to a boil again.

Place the lemongrass, kaffir lime leaves, galangal, garlic, and shallot in the boiling water, and let it simmer for fifteen minutes. Keep the pot cover to prevent the stock from reduced too much.

It takes slightly longer to extract the flavor since I do not bash the lemongrass and tear the kaffir lime leaves. If you have done so, ten minutes should be enough to extract the taste of these ingredients.

After fifteen minutes, remove these ingredients from the stock. You can leave them inside and proceed to the next step, but I think the amount of these unpalatable ingredients is too much, and therefore decided to remove it.  I will choose some nice-looking pieces to add back to the stock as garnishing at a later stage.

d. Add the main ingredients

Add the mushrooms to the stock. When it returns to a boil again, add the shrimp, followed by the coriander stems and tomato wedges. This time is also when you should add other ingredients (chicken, squid, fish, etc.)

When the shrimp is cooked through, reduce the heat to low.

e. Season the soup

Now it is time to season the soup with lime juice, Thai chili paste, sugar, and fish sauce.

Add these ingredients into the soup and switch off the stove.

Please note that the flavor of lime juice will be destroyed by heat, and therefore it is best to add only after removing it from heat.

Do a taste test!

The amount of each seasoning ingredient as mentioned in the recipe is the approximate amount.  It depends on how much the stock has been reduced during cooking, the brand of fish sauce (with various degrees of saltiness), and the lime’s freshness.  After all, you are the one who should decide how much of these ingredients should be added to get the perfect balance of sweetness, saltiness, sourness, and spiciness that you want.

The tom yum soup is now ready to serve, the clear tom yum soup (nam sai). You can add one more step to transform it into the creamy version (nam khon),

f. Add evaporated milk and more chili paste (for tom yum goong nam khon)

I serve half of the tom yum soup as the clear soup and keep the other half in the pot to prepare the creamy version.

Add three tablespoons of evaporated milk and two tablespoons of additional Thai chili paste to the soup.

Do a taste test again, as you may need to adjust the taste with the additional milk.

Once you are satisfied with the taste, bring it to a boil and serve. 

Can you freeze the tom yum soup?

I have to be honest that I am not a fan of frozen soup.  It is best to consume the tom yum soup within one to two days for the best flavor. However, if you want to freeze the soup, I suggest you only freeze the soup at the stage after boiling the galangal, lemongrass, and kaffir lime leaves, garlic, and chili.

You still need to prepare the other fresh ingredients after this stage. It does not take too much time as the bulk of the work has been done.

Types of tom yum soup

There are two types of tom yum soups. The first type is a clear broth, which is called nam sai (ต้มยำกุ้งน้ำใส). If you prefer the clear broth, stop and serve it after step (e) in the last section.

The second type is the most common type, which is a creamy red broth. It is added with evaporated milk and more Thai chili paste (hence the color is red).  It is creamier and spicier and is called nam khon (ต้มยำกุ้งน้ำข้น).

Related recipe to Tom Yum soup

Here are my top picks of the best Asian soups for you:

Chinese hot and sour soup is a traditional northern Chinese favorite packed with the acidity of the vinegar, the spiciness of the pepper, and the nuttiness of sesame oil.  I am sure you will love it, just like the tom yum soup!

Soto ayam is a chicken soup that originated from Indonesia.  It is prepared with an entirely different set of herbs and spices than tom yum.  Give it a try.

Egg drop soup is the easiest Chinese soup recipe to prepare. This soup is the perfect choice when you are busy, as you can do it in fifteen minutes.