📝 About This Recipe
Hailing from the Kyushu region of Japan, Yuzu Kosho is a fermented condiment that delivers a high-voltage shock of citrus fragrance and chili heat. This vibrant green paste balances the floral, aromatic zest of underripe yuzu fruit with the sharp bite of Thai bird's eye chilies and sea salt. It is an essential pantry staple that transforms from a simple preserve into a complex, umami-rich flavor bomb after a short period of aging.
🥗 Ingredients
The Citrus Base
- 10-12 pieces Green Yuzu Fruit (Firm, unblemished skin; substitute with 6 limes and 2 grapefruit if unavailable)
- 2 tablespoons Yuzu Juice (Freshly squeezed from the zested fruit)
The Heat
- 100 grams Green Thai Bird's Eye Chilies (Seeds removed for a smoother paste and controlled heat)
- 2 pieces Green Serrano Peppers (To add body and a grassy depth to the spice profile)
The Preservative & Umami
- 15-20% of total weight Fine Sea Salt (Crucial for fermentation; usually about 1.5 to 2 tablespoons)
- 1/2 teaspoon Kombu Powder (Optional, for a subtle boost of natural MSG)
👨🍳 Instructions
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1
Thoroughly wash the yuzu fruit and chilies in cold water and pat them completely dry with a lint-free towel. Any residual moisture can introduce unwanted bacteria during the aging process.
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2
Using a microplane or a fine Japanese grater, zest the yuzu fruit. Be very careful to only remove the bright green outer layer; the white pith underneath is extremely bitter and will ruin the delicate flavor.
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3
Place a small bowl on a digital kitchen scale and weigh the collected yuzu zest. Note this number down.
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4
Prepare the chilies by wearing gloves to protect your hands from the capsaicin. Stem the chilies, slice them lengthwise, and scrape out the seeds and white membranes.
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5
Finely mince the deseeded chilies by hand or pulse them in a clean spice grinder until they reach a consistency similar to the zest.
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6
Add the processed chilies to the bowl with the yuzu zest and weigh the mixture again. The total weight of zest and chili determines your salt content.
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7
Calculate 15% to 20% of the total weight (zest + chilies) and add that exact amount of fine sea salt to the bowl. For example, if your mixture weighs 100g, add 15-20g of salt.
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8
Add the kombu powder if using, and 1-2 tablespoons of the fresh yuzu juice to help bind the ingredients into a thick, coarse paste.
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9
Transfer the mixture to a mortar and pestle (suribachi). Grind the ingredients together in a circular motion for 5-10 minutes until the salt is dissolved and the oils have emulsified into a uniform green paste.
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10
Taste a tiny amount. It will be very salty and sharp at this stage—this is normal. The flavors will mellow and marry during fermentation.
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11
Pack the paste tightly into a sterilized glass jar, pressing down to remove any air pockets.
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12
Wipe the inner rim of the jar clean, seal tightly, and store in the refrigerator. Let it age for at least 1 week (ideally 2 weeks) before using to allow the fermentation to work its magic.
💡 Chef's Tips
Use a digital scale for precision as the salt ratio is vital for safe preservation. Always wear gloves when handling large quantities of bird's eye chilies to avoid chemical burns. If you cannot find fresh yuzu, a mix of lime zest and a touch of lemon/grapefruit zest mimics the floral notes well. For a 'Red Yuzu Kosho,' simply substitute the green chilies with ripe red chilies and use yellow (ripe) yuzu zest. Ensure all equipment is sterilized with boiling water or high-proof alcohol before use to prevent mold.
🍽️ Serving Suggestions
Whisk a teaspoon into a simple vinaigrette for a bright, spicy salad dressing. Serve a small dollop alongside grilled wagyu beef or fatty tuna sashimi to cut through the richness. Stir into a bowl of hot Tonkotsu ramen just before eating for a citrusy kick. Mix with softened unsalted butter to create a compound butter for grilled scallops or corn on the cob. Add a tiny amount to a gin and tonic for a sophisticated, savory twist on a classic cocktail.