Fermented Lime & Chilli Paste (Makrut Lime Kosho)

A versatile flavour punch for a variety of meals!

Kosho is a (traditionally Japanese) condiment or spicy paste that is used to liven up & add flavour to a wide variety of meals. Combining the double whammy of citrus and chilli, this fermented blend usually features the north Asian fruit Yuzu. Here, we’ve swapped the yuzu out for makrut lime, better known as kaffir lime.

Makrut limes have a distinct crinkly rind and ‘double’ leaves

Makrut, or kaffir limes, are a tropical south-east Asian fruit mostly grown for their highly fragrant leaves, which feature in many curry dishes. Naturally, they grow very well here in the subtropics, yet the plentiful fruit prove a culinary challenge due to their bitter pulp.

Makrut lime kosho is strong and salty, so a little can go a long way. It might also be spicy, depending on which chillies you use. This is a versatile ingredient which can be used as a sandwich spread, a marinade, as a topping for grilled fish & meats, and so much more. Add to a ramen soup, spice up a casserole, bulk out a salad dressing, top eggs or oysters with it, or use as the base for a dip on a grazing platter.

Makrut lime kosho is a fermented product, so will last for 1-2 years if stored correctly. Once opened, it should be kept in the refrigerator. It’s flavour will be at its peak during the first 5 months, by which time you’ll probably have eaten it anyway!

A note on the name. While this fruit has always been known as makrut lime in Thailand (whose cuisine features it heavily), the name of this fruit has evolved with time. Assigned the name ‘kaffir lime’ by a Scottish botanist in 1910, the word ‘kaffir’ has moved from one of proud self-identification to one with negative connotations in some regions. For this reason, we prefer to call it the makrut lime.

Makrut lime kosho

Here’s How to Make It

Assemble your ingredients- picked fresh from the garden, ideally! Zest all the makrut limes & add the zest to your mortar.

Finely chop the lemongrass and chillies, and add them to the mortar.

De-vein & chop the lime leaves and add them to the mortar. Juice the lime then add the lime juice, sugar & salt.

Grind the ingredients together. The mixture will slowly gain more liquid as the solids break down. You can use a food processor instead of a mortar & pestle if you prefer, but the mortar & pestle makes for easier decanting plus it squeezes essential oils & juices out in a way that blades can’t.

Move the kosho into a sealed jar and refrigerate. Leave it to ferment for at least a few days before use.

Fermented Lime Chilli Paste (Makrut Lime Kosho)

A versatile flavour punch for a variety of meals!
Prep Time 20 minutes
Course Condiments
Cuisine fusion
Servings 10


  • 1 Knife
  • 1 chopping board
  • 1 Grater
  • 1 mortar & pestle
  • 1 small sterilised storage jar


  • 12 makrut limes aka kaffir limes
  • 3 whole small chillies
  • 1 stalk lemongrass
  • 4 makrut lime leaves aka kaffir lime leaves
  • 1 tsp salt
  • 1 pinch sugar
  • 1 tbsp lime juice use juice from any standard lime


  • Kest the limes straight into the mortar.
  • Finely chop the chillies (wear gloves if you need to!) then add to the mortar.
  • Top & the lemongrass, then peel off the outer layers until the softer centre section remains. Fine chop this, then add to the mortar.
  • De-vein the lime leaves then chop them finely & add to the mortar.
  • Add the sugar & the salt to the mortar.
  • Grind all the ingredients together in the mortar & pestle until a fine paste is achieved.
  • Add the lime juice and stir until well combined.
  • Decant to a sterile, labelled jar and store in the fridge.
Keyword chilli, chilli paste, fermented, flavour paste, lime, southeast asian
Tried this recipe?Let us know how it was!

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