Sa Tế — Vietnamese Lemongrass Chilli Oil (Ớt Sa Tế)

September 18, 2009

Sa Tế — Vietnamese Lemongrass Chilli Oil (Ớt Sa Tế) © kvalifood.com

Sa Tế is a Vietnamese chilli-lemongrass oil that works as both a condiment and a cooking ingredient. The name comes from satay (the Southeast Asian skewered meat), but the sauce itself is nothing like peanut satay sauce - it’s an aromatic chilli oil built on lemongrass, garlic, shallots, and dried chilli, slow-fried in oil until everything is fragrant and deep red.

It shows up across southern Vietnamese cooking. A spoonful goes into bò kho (beef stew) and bún bò Huế (spicy beef noodle soup). It sits on the table at phở restaurants for people who want heat. It works as a marinade for grilled meats, a stir-fry base, or stirred into a bowl of noodles.

The colour comes partly from the chillies and partly from annatto seeds (hạt điều), which are steeped in oil to produce a bright red-orange tint. Some versions also include star anise and cinnamon bark for warmth. The key flavour, though, is always lemongrass - that’s what separates sa tế from Chinese chilli oil or other Asian chilli pastes.

Store-bought sa tế (brands like Bà Giáo or Cholimex) is widely available at Asian grocers and works fine. But the homemade version is noticeably more fragrant, especially when the lemongrass is fresh.

This page has two versions: a quick blended sauce that uses Hoi An chilli sauce as a shortcut, and a traditional from-scratch sa tế oil.

Version 1: Quick Chilli Satay Sauce (Sốt ớt sa tế)

A quick Vietnamese satay-style chilli sauce built on Hoi An chilli sauce as its base. It’s sweet, salty, sour, and spicy all at once - good with grilled meats, noodles, or as a dipping sauce. Takes about a minute to put together if you already have the Hoi An chilli sauce on hand.

Ingredients

1 tbsp Hoi An chilli sauce (see recipe on this page)
1 tsp sugar
2 tsp soya sauce
½ tsp black vinegar
1 tsp water

Directions

Combine the sugar, soya sauce, black vinegar, and water in a small bowl. Stir until the sugar dissolves completely.
Add the Hoi An chilli sauce and mix well.

Notes

Vietnamese chilli satay sauce can also be purchased from an Asian grocer if you want a shortcut.
This relies on the Hoi An chilli sauce recipe - make that first or substitute a store-bought chilli garlic sauce.

Version 2: Traditional Sa Tế (Lemongrass Chilli Oil)

The real thing. This is a slow-fried chilli-lemongrass oil - closer to a chilli crisp than a sauce. It takes about 30-40 minutes of low-heat cooking, but makes a large batch that keeps for weeks in the fridge.

Makes about 350 ml (1½ cups).

Ingredients

Annatto oil:

250 ml (1 cup) neutral oil (vegetable, canola, or peanut)
2 tbsp annatto seeds (hạt điều)

Aromatics:

125 ml (½ cup) neutral oil
5 stalks lemongrass, tender white/light green parts only, very finely chopped
50 g shallots (about 2-3 medium), finely minced
30 g garlic (about 6 cloves), finely minced
1 star anise
1 small piece cinnamon bark (about 3 cm)

Chilli and seasoning:

100 g fresh red chillies (Thai bird’s eye or similar), finely chopped
3 tbsp dried chilli flakes (gochugaru or similar, not Sichuan)
1 tbsp fish sauce
1 tsp sugar
½ tsp salt

Directions

Make the annatto oil. Heat 250 ml oil with the annatto seeds in a small saucepan over low heat. Stir gently for 3-5 minutes until the oil turns deep red-orange. Strain out the seeds and set the oil aside.
Fry the aromatics. Heat 125 ml oil in a medium saucepan over medium-low heat. Add the star anise and cinnamon bark and let them sizzle gently for 1-2 minutes until fragrant. Remove the spices with a slotted spoon.
Add the lemongrass to the oil and cook on medium-low for about 5 minutes, stirring often. The goal is to soften and release the fragrance - not to brown it.
Add the shallots and cook for another 3-4 minutes, stirring regularly.
Add the garlic and cook for 3-4 minutes more. Keep the heat low enough that nothing burns or turns dark.
Add the fresh chillies, dried chilli flakes, fish sauce, sugar, and salt. Stir everything together and cook on low heat for about 10 minutes, stirring occasionally. The mixture should bubble gently, not sputter.
Pour in the annatto oil and stir to combine. Cook for another 1-2 minutes.
Remove from heat and let it cool completely before transferring to a clean glass jar.

Storage

Keeps in the fridge for up to a month in a sealed glass jar. Some people report it lasting much longer - an oil layer on top helps. For longer storage, freeze portions in ice cube trays.

Notes

Low heat throughout. This is the single most important thing. High heat will burn the garlic and lemongrass and make the sauce bitter. If anything starts to brown too fast, pull the pan off the heat and lower the flame.
Lemongrass prep matters. Use only the tender lower portion of the stalk (the bottom 10-12 cm after peeling outer layers). A food processor helps get it fine enough - you want a near-paste, not chunks.
The annatto seeds are for colour, not flavour. If you can’t find them, skip them. The sauce will be less red but taste the same.
Galangal (about 20 g, minced) is an optional addition found in some southern Vietnamese versions.
Some recipes add a teaspoon of paprika for extra colour if annatto isn’t available.

Quick Version vs. Traditional: What’s the Difference?

The quick version (Version 1) is a blended dipping sauce - it tastes good but it’s a different product. It’s thin, saucy, and gets its heat and flavour from the Hoi An chilli sauce base.

The traditional sa tế (Version 2) is an oil-based condiment with body and texture. The lemongrass, garlic, and chilli bits sit in the oil and add crunch. It’s richer, more aromatic, and more versatile - you can cook with it, not just dip into it.

If you’re making bò kho, bún bò Huế, or want something to stir into phở, the traditional version is what you want. The quick version works well as a table sauce for spring rolls or grilled meats.