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A glass jar filled with vibrant green yuzu kosho paste, made from a traditional Yuzu Kosho Recipe, sits on a wooden tray beside a wooden spoon and a whole green citrus fruit. Plates and utensils are arranged in the background.

Yuzu Kosho

by Namiko Hirasawa Chen
Yuzu Kosho is a fermented Japanese condiment made from green yuzu zest, green chilis, and salt—spicy, salty, and citrusy in one bite, and far more vibrant than anything store-bought. A small dab adds punch to soups, grilled meats, dressings, or rice. The final photos show a double portion (100 g).
Prep: 30 minutes
Fermenting Time (See Notes): 7 days
Total: 30 minutes
Servings: 1 small jar of (50g) yuzu kosho paste

Ingredients

Servings: 1 small jar of (50g) yuzu kosho paste
  • 25 g green yuzu zest (~15 small fruits; washed and dried; optional yuzu juice to bind the paste)
  • 25 g fresh green chilis (~3 serrano peppers—closest swap for ao togarashi; stemmed and seeded)
  • 7.5–10 g Diamond Crystal kosher salt (15–20% of yuzu + chili weight; ~2⅔ tsp to 1 Tbsp)

Instructions

Before We Start

  • Gather all the ingredients. Fruit sizes vary, so buy a little extra of each.
    To sterilize the jar, boil or steam a glass jar for 10 minutes, then air-dry upside down on a clean towel.
    Note: Green yuzu is usually the harder ingredient to source, so zest and weigh it first, then match that exact weight in chilis for a true 1:1 ratio.
    On the left: fresh green chilies, limes, and a bowl of salt on a wooden surface—perfect ingredients for a homemade Yuzu Kosho Recipe. On the right: glass jars being sterilized in boiling water in a pot on a stove.

To Zest the Yuzu

  • Microplane the peel. Avoid the bitter white pith. Weigh the zest on a digital scale—this is your base weight (e.g., 25 g).
    A person grates green zest from a lime, with the zest being weighed on a digital kitchen scale showing 21.9 grams—perfect for adding vibrant citrus flavor to your next Yuzu Kosho recipe.
  • (Optional method: Peel with a knife or vegetable peeler, then trim off the white pith.)
    A cut lime with zest and a peeler on a wooden board, and a hand slicing lime peel strips with a knife on the same board—essential preparation steps for an authentic Yuzu Kosho recipe.

To Prep the Chilis

  • Wear food-safe gloves. Trim the stem, halve chilis lengthwise, and scrape out the seeds.
    Nami’s Tip: Gloves prevent painful accidental burns. Capsaicin lingers on skin for hours and will cause a severe burn if you accidentally touch your eyes.
    A person wearing gloves slices green chili peppers and removes their seeds on a wooden cutting board and a metal tray, carefully preparing the ingredients for an authentic Yuzu Kosho recipe.
  • Use a small paring knife to slice away any remaining white pith.
    Weigh the prepped chilis to match your yuzu zest weight exactly (e.g., 25 g)
    Three images: slicing and deseeding a green pepper with a knife on a cutting board—a key step in preparing ingredients for Yuzu Kosho Recipe—the pepper halves displayed, and the halves weighed on a digital scale showing 25.7 grams.

To Grind to a Paste

  • Transfer the chilis and zest to a food processor.
    Two images: On the left, a hand adds green peppers to an empty food processor, beginning the first step in a Yuzu Kosho recipe. On the right, the processor contains finely chopped green peppers. Both are on a wooden surface.
  • Pulse, scraping down the sides as needed, until finely chopped.
    Nami’s Tip: For a smoother, traditional texture, finish by hand in a mortar and pestle—it releases even more citrus oils for an incredibly aromatic paste!
    Three images show hands using a food processor to blend green herbs for a Yuzu Kosho Recipe, then scraping the mixture down with a spatula, and finally the finely chopped herbs inside the processor.

To Calculate and Add the Salt

  • Place a bowl or mortar on a digital scale. Transfer the paste and record the total weight.
    Calculate 15%–20% of the paste weight in salt (e.g., 7.5–10 g salt for 50 g paste).
    Chopped green herbs are poured into a bowl on a kitchen scale, an essential step in preparing a Yuzu Kosho recipe. In the next image, the scale shows the bowl with herbs weighs 49.1 grams.
  • Weigh the calculated salt and mix in thoroughly (grinding with a mortar and pestle) until fully dissolved and hydrated.
    Nami’s Tip: Only add a small drizzle of fresh yuzu juice if the paste looks dry—the salt usually draws out plenty of moisture naturally.
    Three photos illustrate the Yuzu Kosho Recipe: sugar is weighed on a scale in a glass bowl, poured into a bowl of green herbs, then mixed and mashed with a wooden pestle until combined.

To Jar It

  • Transfer paste into your sterilized glass jar, pressing out air pockets.
    Lay a small piece of parchment paper directly on top of the paste surface. Close the lid tightly to create an anaerobic environment.
    Nami’s Tip: Pressing out air pockets and sealing well prevents top oxidation, keeping the entire jar bright and fresh.
    Three panels showing: spooning green herb paste into a glass jar, pressing the paste down with fingers, and sealing the jar with a glass lid and metal clasp—perfect steps for preparing a homemade Yuzu Kosho Recipe.

To Ferment and Age

  • Rest at room temperature for 24 hours (if your kitchen is cool), then transfer to the refrigerator.
    Age in the fridge at least 7 days (2 weeks recommended) to mellow raw heat and develop a rounded flavor.
    Two photos show a glass jar filled with green paste, likely a Yuzu Kosho recipe or herb blend, on a wooden tray with fresh green citrus fruits nearby. The jar is open in one photo and closed in the other.

To Store

  • Keep in the fridge for about 6 months. Freezes exceptionally well without turning solid—scoop straight from frozen whenever needed.

Notes

Ingredients & Substitutions

  • Yuzu zest: Swap in lemon or lime zest.
  • Green chilis: Serrano pepper is the closest match in flavor and heat to Japanese ao-togarashi. You can also use jalapeño, Thai chili, or habanero.
  • Salt: Use pure kosher or additive-free sea salt. Do not go below 15% salt by weight to prevent spoilage during fermentation. Avoid iodized salt, which can hurt the ferment.

To Use Leftover Yuzu

Here are a few great ways to make use of the remaining fruit:
  • Yuzu ponzu: Juice the fruit and follow my Yuzu Ponzu recipe.
  • Green yuzu syrup: Layer sliced fruit with sugar or honey until dissolved, then dilute with water.
  • Yuzu ice cubes: Freeze strained juice in ice trays for dressings or Japanese Cucumber Salad.

How to Use (Quick Ideas)

See post above for full variation ideas!
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