It’s officially cold noodle season, and I’m fully committed to the trend. Lately I came across the recipe for cold lemon somen from harus_cuisine and knew immediately I had to make my own version.

So I tweaked it to make it heatwave-friendly: no dashi step, just instant granules, a punchy homemade mentsuyu-based broth, and plenty of lemon. That’s really it.

It hits the spot incredibly well — refreshing and light, while still being satisfying enough to count as a real meal, not just a snack.

Chilled Lemon Soba – About the dish

Soba (そば) are Japanese buckwheat noodles, eaten across Japan since at least the Edo period (17th century). Served cold in the warmer months, they’re one of the country’s oldest and most cherished noodle traditions, traditionally paired with a savoury dipping sauce called mentsuyu.

Mentsuyu itself is a concentrated sauce built on dashi (Japanese stock), soy sauce and mirin. Making dashi from scratch is traditional, but here we lean on instant dashi granules and a bottled mentsuyu concentrate to keep things fast — not really a shortcut, just smart, heatwave-appropriate cooking.

The lemon is where this version drifts from tradition. Instead of dipping noodles bite by bite into a separate sauce, everything sits together in one chilled, citrusy broth — closer to a cold noodle soup than the usual zaru style. It’s a small change, but it makes the whole dish brighter without adding a single extra step at the stove.

Chilled Lemon Soba – Recipe

Ingredients – Advice & key points

• Dried soba: 180g is enough for two servings. Follow the package timing closely — soba overcooks fast, and a few extra seconds turns it gummy. Any buckwheat or blended soba works.
• Very cold water: needed for rinsing the noodles after cooking. The colder, the better — it stops the cooking and washes off the surface starch that would otherwise cloud the broth and make the noodles clump.
• Concentrated mentsuyu: the base of the broth. A bottled concentrate from an Asian grocery store already carries the soy sauce, mirin and dashi flavour, so you’re not building anything from scratch.
• Instant dashi granules: optional but recommended. A small pinch deepens the umami without needing to simmer a proper dashi from scratch.
• Lemon: both zest and juice go into the broth, plus a few thin slices as topping. Use an untreated or organic lemon if you can, since the zest infuses directly into the liquid.
• Ice cubes: added to each bowl at serving. Don’t skip them, this dish only works properly cold.
• Cucumber: adds crunch and freshness. Slice it thin so it doesn’t overpower the noodles.
• Toasted sesame seeds: a finishing touch for texture and a nutty note. Toast raw seeds yourself in a dry pan for a minute or two if needed.

Recipe – Advice & key points

• Let the zest infuse properly: 20–30 minutes in the fridge is the sweet spot. Any less and the lemon flavour stays shallow.
• Taste before adding ice: the broth will be diluted once the ice cubes go in, so it should taste slightly stronger/saltier than you want the final dish to be.
• Shock the noodles hard: rinse them under very cold running water right after draining, rubbing gently between your hands. This removes excess starch and gives soba its clean, springy bite once chilled.
• Assemble at the last minute: pour the broth over the noodles only when you’re ready to serve, and add the ice cubes straight into each bowl so nothing has time to go lukewarm.

Credit to harus_cuisine for the original idea — this version is just a heatwave-friendly remix. Enjoy!

Print Recipe

Chilled Lemon Soba

Author: Multicarbs Cuisine: Asian cuisines, Japanese cuisine Courses: Main dish, Pasta

Prep Time 10 min Cook Time 5 min Rest Time 25 min Total Time 40 mins

Servings: 2

Description

Chilled soba noodles in a bright lemon dashi broth, topped with cucumber, lemon slices and toasted sesame seeds — a heatwave-proof, no-fuss summer bowl.

Ingredients

Servings

Noodles

• 180 grams dried soba
• very cold water (for rinsing)

Lemon Dashi Broth

• 400 milliliters cold water
• 3 tablespoons concentrated mentsuyu (start with 2,5 then adjust)
• ¹⁄₃ teaspoon instant dashi granules (optional but recommended)
• ¹⁄₂ lemon (zested and juiced)
• 4 large ice cubes

Toppings

• ¹⁄₃ cucumber, thinly sliced
• 4 thin lemon slices
• 1 tablespoon toasted sesame seeds

Instructions

Instructions

1. Make the broth

   In a bowl or jug, whisk together the water, mentsuyu, lemon juice and dashi powder until dissolved.

   Add the lemon zest and let it infuse in the fridge for 20-30 minutes.

   Taste and adjust if needed, keeping in mind that the broth will be diluted by the added ice

2. Slice your toppings & cook the soba

   While you wait, thinly slice your cucumber and lemon. Top your cucumber slices with some lemon juice and salt and let it sit. 

   Cook the soba according to the package instructions (usually about 3 minutes).

   Drain immediately and rinse under very cold running water until completely cooled. Drain again well.

3. Assemble

   Divide the soba between two bowls. Top with the cucumber, lemon slices and sesame seeds.

   Pour the chilled broth over the noodles, then add 2 large ice cubes per bowl. Serve immediately.

Keywords: soba, lemon, cold noodles, dashi, mentsuyu, Japanese, summer, chilled noodles