Prik Nam Som (Thai Chili Vinegar Sauce): Easy Authentic Recipe

Want to brighten up any Thai dish with that authentic punch of tangy heat you remember from eating in Thailand? Prik Nam Som is one of the easiest Thai sauces to make, and it brings instant life to your fav Thai dishes!

What is Prik Nam Som?

Prik Nam Som is at its simplest just chilies and vinegar, and when you toss them together they become a vibrant, no-cook sauce that wakes up your whole meal.

It’s the same tangy sauce my Thai Hubby grew up with in Sukhothai. He used it at every noodle stall there and really all over Thailand.

Fun fact: Thais love customizing their dishes at the table, and Prik Nam Som is a huge part of that. When you sit down at a noodle stall, you’ll always see the classic Thai “four seasonings” tray, sugar, fish sauce, chili flakes, and the chili vinegar. Now you can make it at home in just a few minutes and feel like you’re sitting at a street stall in Thailand as you drizzle it over your noodles.

And if you’re building out your Thai sauce collection, don’t miss my Prik Nam Pla, my Thai Flavor Bomb Sauce, my Pad Thai Sauce that tastes like the one on the streets of Thailand, or my 5 Minute Thai Garlic Lime Seafood Sauce that’s packed with chilies and garlic!

Why You’ll Love This Recipe

• Authentic flavor – This is the real deal, the same Prik Nam Som my Thai Hubby grew up with and the one I teach in my Thai cooking classes.
• So fast – Stir it together in minutes, no cooking needed. Thai Hubby was shocked I was even writing a recipe for it because it’s so easy!
• Flexible – Spoon it over Chicken Pad See Ew, drizzle on Lad Na, or brighten any rich Thai dish.

Prik Nam Som Ingredients You’ll Need

• 2–3 serrano chilies or spur chilies (Prik Chee Fah), thinly sliced 1/4 inch thick – Traditional Prik Nam Som is made with spur chiles, a mild long red Thai chili. I can never find them in America, so I use serrano as a substitute. Serranos have a similar bright flavor and are a nice size when sliced. If you can find spur chilies, definitely use them.
• 1/2 cup white vinegar – Gives the sauce its classic tangy backbone. Use regular cheap white vinegar here. You don’t want anything fancy or flavored that would compete with the clean, bright taste this sauce is known for.
• Pinch of salt (optional) – Some noodle shops add a small pinch to round out the acidity, but many don’t. Totally optional.

How to Make Prik Nam Som

STEP 1: SLICE YOUR CHILIES

Slice the chilies into thin 1/4in. slices. Remove some seeds if you want it milder.

STEP 2: MIX THE BASE

In a small bowl, stir together the Serranos and white vinegar. Let it sit for at least 5 minutes, which allows the flavors to bloom.

STEP 3: TASTE + ADJUST

More vinegar for tang. More chilies for heat. Thai cooking is all about tasting and tweaking until it matches your palate. Store Prik Nam Som in a clean glass jar in the fridge for up to 1 week for the brightest flavor.

STEP 4: USE IT

Prik Nam Som is one of the easiest ways to add brightness, heat, and that nostalgic Thai flavor to your meal. Try it on:

Lad Na – The tangy vinegar cuts through the silky gravy perfectly.
Chicken Pad See Ew – Balances the sweet soy sauce with a clean, bright kick.
Sukhothai Noodle Soup – Adds that classic table-side tang you taste in shops all over Sukhothai.

Or keep it on the table like Thais do and add it to whatever needs a little zing!

Additions and Substitutions

• Serrano or spur chili substitute: Red jalapeños if you can find them. They’re just ripe jalapeños, so they’re sweeter and a little milder, and look closer to the long red chilies used in Thailand. Green jalapeños or Thai chilies work too, but they’ll be spicier.
• White vinegar substitute: Unseasoned rice vinegar or apple cider vinegar. Avoid seasoned rice vinegar since it has added sugar and salt that change the flavor.

Tips for the Best Prik Nam Som

Let it sit: Give it at least 5 minutes so the chilies soften and the flavors meld.
Customize it: Add more chilies if you love heat.
Make ahead: This sauce keeps in the fridge at least a week and it tastes even better the next day as the flavors deepen.

Behind the Prik Nam Som Recipe

When I was researching this recipe, I did what I always do. I pulled out my Top Five Thai Cookbooks, checked the online Thai recipes from Thai chefs Thai Hubby and I trust, and then finished by asking him how he likes his Prik Nam Som, because at the end of the day our Thai recipes come back to whatever his family grew up eating in Sukhothai

But when I asked him about Prik Nam Som, he just stared at me like I wasn’t saying it right in Thai. He had no idea what I was talking about.

When I explained, “You know, the chilies and vinegar you spoon over Lad Na,” he laughed and said, “Oh, you mean prik nam som sai chu!”

That moment reminded me how Thais almost never call this sauce by one formal name. It’s usually called by what it is, not a “recipe title.”

Thais might say things like:

• “น้ำส้มพริก” (nam som prik): chili vinegar
• “น้ำส้มใส่พริก” (nam som sai prik): vinegar with chilies
• “พริกดองน้ำส้ม” (prik dong nam som): chilies pickled in vinegar
• “พริกน้ำส้มใส่ฉู” (prik nam som sai chu): vinegared chilies, the term Thai Hubby grew up hearing

All of those mean the exact same thing, but the phrasing changes depending on the family, the vendor, or the region.

And honestly, Prik Nam Som is so everyday in Thailand that most people don’t label it at all. At noodle shops in Bangkok, no one thinks, I want to add some Thai chili vinegar sauce to my soup. 

They think, Hmm, this could use a little more sour flavor, and reach for the jar of vinegar with chilies floating in it.

It’s treated more like a seasoning than a “recipe,” which is why everyone has a slightly different name for it and why Thai Hubby was so confused when I tried to give it an official title.

Once we realized we were talking about the same thing, he told me the traditional chili used is Prik Chee Fah (spur chilies), the long mild red Thai chili you see sliced on street food. I can never find them here in America, so I use serranos. Thai Bird’s eye chilies work too if that’s what you have, but they’ll make the sauce spicier than the classic version you’d find in Thailand.

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Prik Nam Som Frequently Asked Questions

Want more Thai sauces and curry pastes to keep the flavor going?

• Tom Yum Paste – Bright and citrusy, perfect for quick soups.
• Massaman Curry Paste – A cozy blend of warm Thai spices.
• Panang Curry Paste – Rich, slightly sweet, and full of bold chili flavor for creamy Thai curries.

And if you want to learn how to make this and other sauces in person, come join one of my Thai cooking classes in Boone, NC!

Love learning Thai kitchen tips like this? Sign up for my Thai-Foodie Substack newsletter and get my free Substitution Hacks Guide download, your cheat sheet for swapping Thai ingredients no matter where you live!

If you make it, I want to see! Take a pic and tag me on Instagram @thaifoodie!

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