Hot and Sour Soup

Hot and Sour Soup is the thick, peppery Chinese restaurant soup with pork, tofu, mushrooms, and egg ribbons, and I make it with the vinegar and the pepper going in at the very end. A long simmer flattens vinegar. Add it early and you may need more because the sourness fades as it simmers. Off the heat, what you pour in is what you taste. Everything before that is a plain pot of broth, meat, and vegetables cut into strips.

Two ingredients decide whether this tastes like the bowl you get at a Chinese restaurant, and neither one is the vinegar. They are ground white pepper and wood ear mushrooms. White pepper is where that earthy warmth comes from, and wood ear gives the soup a soft crunch that nothing else in the pot can stand in for. Both are cheap, both keep for months in the cupboard, and one trip to a Chinese grocery covers you for several batches.

The cornstarch and the egg do two different jobs, so they go in one at a time. Stir the slurry in first and let the broth thicken, then bring the pot down to a gentle simmer before the beaten eggs go in. A thickened broth holds the egg together into long ribbons instead of scattering it, and it is the same pour I use for my egg drop soup.

What is Hot and Sour Soup?

Hot and Sour Soup is a Chinese soup of pork, tofu, mushrooms, and bamboo shoots in a cornstarch-thickened broth, soured with vinegar and made hot with ground white pepper, then finished with beaten egg poured in as ribbons. The Chinese name is suan la tang, which reads straight across as sour spicy soup. You will also see it labeled as Sichuan hot and sour soup on many Chinese restaurant menus, even though the soup is also traced to Henan.

The American Chinese version is generally thicker because of the cornstarch. That thickness also makes it filling enough to serve as a first course or a light meal.

Ingredients

For the soup

• Pork – Any lean cut you can slice thinly. I cut it across the grain into strips about as wide as the carrot sticks, so everything sits on the spoon together.
• Shiitake mushrooms – Fresh is fine, since they get 12 minutes in the broth. Dried ones taste stronger, and their soaking water can go into the pot as part of the liquid.
• Wood ear mushrooms – Sold dried, in a clear bag, at any Chinese or Filipino Chinese grocery. No wood ear at your store? See the substitutions below.
• Ginger – Sliced into coins rather than minced, so anyone who does not want a mouthful of ginger can push the pieces aside.
• Firm tofu – Firm, not silken. Soft tofu falls apart the moment you start stirring the slurry through.
• Carrots – Julienned thin. They only get about 3 minutes in the pot, so thick sticks stay raw in the middle.
• Bamboo shoots – I use the canned sliced ones, drained and rinsed. The liquid in the can has a tinny smell that carries into the broth.
• Chicken broth – Low sodium if you can find it, since the soy sauce is bringing salt of its own.
• Soy sauce – Regular all-purpose soy sauce. Three tablespoons colors the broth without making it taste like soy sauce.
• Sugar – One teaspoon, and it will not make the soup sweet. It rounds off the edge of the vinegar.

To thicken and finish

• Cornstarch and cold water – Equal amounts of each, and the water has to be cold. Warm water starts setting the starch in the bowl.
• Eggs – Beat them until no streak of white is left, or you get a rubbery patch in the finished soup.
• Rice vinegar – Get the unseasoned kind. Seasoned rice vinegar already has salt and sugar in it, which throws off the seasoning at the end. No unseasoned rice vinegar? See the substitutions below.
• Toasted sesame oil – A finishing oil. Its aroma fades with cooking, so I add it after turning off the heat.
• Cayenne pepper powder – A quarter teaspoon is mild. You can push it up after you taste.
• Ground white pepper – A teaspoon, and buy it already ground in a small jar. It is in the spice aisle of most Asian groceries.
• Salt – Last, after the soy sauce and the vinegar are both in.
• Spring onions – Chopped fine and scattered over the bowls.

About the Wood Ear Mushrooms

Wood ear is a thin black fungus sold dried, and it tastes of almost nothing on its own. What it gives the soup is a soft, slightly crisp bite that holds up well during simmering. That texture is one of the things I look for in Hot and Sour Soup.

A small handful swells to several times its dry size, so a half cup of dried pieces goes further than it looks. Soak them in warm water for about 20 minutes, until they feel soft and rubbery rather than papery. Cut away the hard knot at the base of each piece before slicing, because that knot stays tough no matter how long it simmers. Restaurant-style recipes often ask for dried lily flower alongside it, sometimes with a soak of an hour or more. This one leaves the lily flower out, and 20 minutes is the longest anything here needs to sit in water.

Start the broth and let the pork and mushrooms simmer while you mix the cornstarch and beat the eggs. Once the broth thickens, the egg and final seasonings go in quickly.

1. Pour the chicken broth into a cooking pot and bring it to a boil.
2. Add the shiitake mushrooms, wood ear mushrooms, ginger, and pork.
3. Reduce the heat and simmer for 12 minutes.
4. Add the bamboo shoots and carrots, then simmer for 3 minutes.

Keep it at a low bubble once the pork is in rather than a rolling boil. Thin slices tighten up in a hard boil. Twelve minutes at a simmer leaves them tender and no longer pink through the middle.

1. Add the tofu, soy sauce, and sugar. Stir gently and let the soup return to a gentle simmer.
2. Combine the cornstarch and cold water in a small bowl.
3. Slowly pour the mixture into the soup while stirring.
4. Continue cooking until the broth thickens.

Pour the slurry in a thin stream rather than tipping it in at once. A quarter cup of cornstarch is a lot for one pot, and a fast pour leaves lumps that will not stir out once the broth is hot.

1. Slowly drizzle the beaten eggs into the simmering soup while gently stirring in one direction.
2. Let the egg set into ribbons, then turn off the heat.
3. Stir in the rice vinegar, sesame oil, cayenne pepper, and ground white pepper.
4. Taste and add more vinegar, cayenne, or white pepper if it needs it, then season with salt.

Pour the egg in a thin stream from a few inches above the pot. The height stretches the stream so it lands across the surface instead of dropping in one place.

1. Transfer the soup to a serving bowl.
2. Garnish with the chopped spring onions. Serve warm. Share and enjoy!

What to Serve with Hot and Sour Soup

• Rice – The broth is thick enough to eat over rice like a sauce, which turns one bowl into a light lunch.
• Egg Fried Rice – The fried rice works well with the thick broth and turns the soup into a more filling meal.
• Kung Pao Chicken – Already carrying its own heat, so keep the soup on the mild side when you serve them together.
• Pork Siomai – Steamed dumplings and a small bowl of soup is how most Chinese meals open here.
• Pinsec Frito – Fried wontons to eat between spoonfuls, so there is something crisp on the table.
• Hot tea – Plain jasmine or oolong. Something unsweetened after a sour, peppery bowl.

Storage

Hot and Sour Soup keeps well in the refrigerator, but I like to reheat it gently so the egg ribbons and tofu stay in good shape.

• Refrigerator – I let the soup cool first, then keep it in a tightly sealed container in the refrigerator for 3 to 4 days. A good lid also helps keep the vinegar smell from spreading. I only reheat what we are going to eat because the tofu gets softer each time the soup is warmed.
• Freezer – I prefer freezing this before adding the cornstarch and eggs. I ladle out the portion I want to freeze once the vegetables are cooked, then add the slurry and eggs after reheating. It keeps well for up to 2 months this way. You can freeze the finished soup too, but the broth may thin after thawing and need a little more cornstarch and water.
• Reheating – I warm it on the stove over medium heat until steaming, but I avoid letting it boil. Boiling can break up the egg ribbons and make the tofu spongy. Taste the soup before serving too. The vinegar can mellow in the refrigerator, so I usually add a small splash if it needs more sourness.

More Soup Recipes

• Chicken and Corn Soup – Cream-style corn and ground chicken in a thickened broth with egg ribbons through it.
• Hototay Soup – Pork, liver, and vegetables in a clear broth, with a whole raw egg cracked into each bowl and cooked by the heat of the soup.
• Pancit Molo – The Ilonggo wonton soup, with pork dumplings and toasted garlic scattered on top.
• Chicken Lomi – Thick miki noodles in a heavy broth, thickened with cornstarch and beaten egg.
• Sotanghon and Egg Noodle Soup – Two kinds of noodle in one clear broth.
• Tofu Balls with Miswa and Patola – Fried tofu balls with thin flour noodles and loofah.

• Pork – Chicken breast cut into thin strips, added at the same point. You can also leave the meat out entirely and use vegetable broth in place of the chicken broth.
• Unseasoned rice vinegar – Plain white vinegar at the same 1/3 cup is the closest match. Chinese black vinegar works too and makes the soup darker and rounder, but start at 1/4 cup because it is stronger.
• Wood ear mushrooms – Another cup of sliced shiitake takes their place. You lose the crunch and nothing else.
• Ground white pepper – Ground black pepper at the same teaspoon.
• Bamboo shoots – Canned water chestnuts, sliced thin, give you a similar crunch. Leaving them out is also fine.
• Cornstarch – Potato starch at the same 1/4 cup. Flour will thicken the soup but the broth turns dull instead of glossy.

Serve Hot and Sour Soup hot with chopped spring onions on top. I like mine a little more peppery, so I usually add a bit more white pepper to my bowl.