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Finished homemade shio kombu — dark dried strips of kelp coated in a fine dusting of white finishing salt and sugar — piled in a clear freezer bag on a kitchen counter

Homemade Shio Kombu from Leftover Dashi Kelp

Turn the spent kombu from making Japanese dashi into a jar of homemade shio kombu — glossy, salty, umami-packed kelp strips that taste better than store-bought. A zero-waste condiment for rice, onigiri, salads, and pasta.
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Prep Time 10 minutes
Cook Time 1 hour
Total Time 1 hour 10 minutes
Servings: 50 grams
Course: Condiment
Cuisine: Japanese
Ingredients Method

Ingredients
  

  • 50 g leftover dashi kombu sliced into 3 mm strips
  • 1 tbsp sugar
  • 1 tbsp mirin
  • 1/2 tbsp rice vinegar
  • 1 tbsp soy sauce
  • 150 ml water
  • 1 tsp unrefined cane sugar for finishing
  • 1/3 tsp finishing salt a flaky sea salt works best

Method
 

  1. Combine sugar, mirin, rice vinegar, soy sauce, and water in a small saucepan. Add the sliced kombu and stir to submerge.
  2. Bring to a gentle boil, then reduce to a low simmer. Stir every few minutes and cook until all the liquid has reduced away and the kombu is glossy — about 30–40 minutes. Let cool in the pot.
  3. Spread the cooled kombu in a single loose layer on a parchment-lined baking sheet. Place in a cold oven, set to 100°C (212°F), and bake for 25–30 minutes. Longer = crispier.
  4. Let cool completely on the tray — the kombu firms up further as it cools.
  5. Drop the cooled kombu into a resealable bag with 1 tsp unrefined cane sugar and 1/3 tsp finishing salt. Seal with a bit of air trapped in and shake gently until every strip is dusted.
  6. Store sealed at room temperature for up to 4 weeks, or in the fridge for 2 months. Use over rice, in onigiri, tossed with cucumber, or crumbled over pasta and salads.