Hiyajiru is a traditional Japanese cold miso soup designed for hot summer days, and in this article you’ll learn exactly how to prepare it at home. Whether you’re searching for a light meal to fit a balanced diet, exploring Japanese cuisine, or curious about simple recipes with cucumber, sesame, and tofu, you’ll find step by step instructions, ingredient insights, and practical tips.
I first discovered Hiyajiru while traveling in Saitama, where it’s often ladled over steamed rice for a cooling yet nourishing lunch. Since then, I’ve recreated it in my own kitchen with dashi stock, roasted sesame, and seasonal vegetables, adjusting it for both vegetarian and pescatarian friends.
Each spoonful is like a whisper of roasted sesame drifting through chilled miso broth, where cool cucumber slices snap against the silky depth of dashi in a rhythm that makes you pause mid-bite.
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What is Hiyajiru?
Hiyajiru is a traditional Japanese cold miso soup made with dashi broth, miso paste, sesame seeds, and seasonal ingredients like cucumber, tofu, and shiso leaves. Originating in Miyazaki Prefecture, it is typically poured over steamed rice and served chilled as a refreshing summer dish. Unlike hot miso soup, Hiyajiru is designed to cool the body in warm weather while still providing protein, minerals, and umami flavor from fermented soybeans and fish based dashi.
Hiyajiru Ingredients
Hiyajiru combines a handful of everyday Japanese pantry staples with fresh summer produce. Each ingredient contributes to the balance of umami, creaminess, and refreshing crunch that defines this cold miso soup.
- Dashi: the savory fish based soup, usually made from kombu (kelp) and katsuobushi (bonito flakes), rich in umami.
- Miso: fermented soybean paste that provides depth, probiotics, and a salty complexity.
- White sesame seeds: toasted and ground to release natural oils, adding a nutty creaminess.
- Tofu: soft or firm cubes for plant-based protein and gentle texture contrast.
- Japanese-style grilled salmon (or mackerel): flaked into the broth, giving smokiness and protein.
- Cucumber: thinly sliced for crisp freshness.
- Shiso leaves (perilla): aromatic herbs with minty, citrus notes.
- Sugar: a small amount balances the saltiness of miso.
- Rice: plain steamed rice, often served with the soup poured over it.
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How to Make Hiyajiru
Making Hiyajiru at home is simple once you prepare the essential components: a chilled miso sesame broth, fresh vegetables, and rice. Follow these steps:
Toast and grind sesame seeds: Use a suribachi (Japanese mortar) or spice grinder until the seeds release fragrant oils.
Mix sesame with miso and sugar: Stir until a smooth paste forms. This creates the flavor base of the soup.
Add dashi stock: Gradually whisk in cold dashi (kombu and katsuobushi broth, or instant granules for convenience) until dissolved. Chill in the refrigerator.
Prepare the protein: Grill salmon (or mackerel) Japanese style, then flake into small pieces. For vegetarian versions, replace with tofu.
Slice vegetables: Cut cucumber into thin rounds and shred shiso leaves for freshness and aroma.
Assemble the soup: Combine chilled broth, fish or tofu, cucumber, and shiso in a large bowl.
Finally adjust saltiness by choosing different miso types (white miso for mildness, red miso for stronger flavor).
Hiyajiru (Japanese Cold Miso Soup)
Ingredients
Method
- Use a suribachi (Japanese mortar) or spice grinder until the seeds release fragrant oils.
- Stir until a smooth paste forms. This creates the flavor base of the soup.
- Gradually whisk in cold dashi (kombu and katsuobushi broth, or instant granules for convenience) until dissolved. Chill in the refrigerator.
- Grill salmon (or mackerel) Japanese-style, then flake into small pieces. For vegetarian versions, replace with tofu.
- Cut cucumber into thin rounds and shred shiso leaves for freshness and aroma.
- Combine chilled broth, fish or tofu, cucumber, and shiso in a large bowl.
Nutrition
Notes
- You can use pre-made dashi granules for convenience.
- Optional grilled fish (like mackerel) adds traditional depth of flavor.
- Make it vegetarian by omitting the fish and using kombu-based dashi.
- Serve with extra ice cubes if eating during a heat wave!
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Let us know how it was!Hiyajiru Udon and Somen Soup Base Straight
While Hiyajiru is traditionally poured over steamed rice, modern adaptations highlight how versatile this cold miso soup can be. Two popular variations are Hiyajiru Udon and recipes that use somen soup base straight for quick preparation.
Hiyajiru Udon
- Replaces rice with thick, chewy udon noodles, creating a heartier meal.
- Often served in summer restaurants across Japan as a cooling alternative to hot noodle dishes.
- Works well with toppings like shredded nori, sesame, and extra shiso.
Using Somen Soup Base Straight
- A convenient shortcut that replaces homemade dashi.
- Bottled soup base (mentsuyu) is usually made from soy sauce, mirin, and dashi, delivering instant umami.
- Ideal for busy cooks who want an easy Hiyajiru recipe without compromising flavor.
Traditional vs Modern Adaptations
| Variation | Base Ingredient | Main Carbohydrate | Best For | Flavor Profile |
|---|---|---|---|---|
| Traditional Hiyajiru | Homemade dashi + miso | Steamed white rice | Authentic experience | Light, savory, refreshing |
| Hiyajiru Udon | Sesame-miso broth | Udon noodles | Filling summer meal | Creamy, nutty, hearty |
| Somen Base Straight | Bottled mentsuyu + miso | Rice or noodles | Quick cooking | Balanced umami, slightly sweet |
Whether you choose the comfort of rice, the chewiness of udon, or the speed of a ready-made somen soup base straight, Hiyajiru adapts easily to different lifestyles and cooking habits.
Serving and Pairing Suggestions
Hiyajiru is more than a soup, it’s a complete seasonal meal when paired thoughtfully. Traditionally served in a chilled bowl, it’s ladled over warm rice to create a contrast between cool broth and steamed grains. For modern variations, udon or somen noodles offer a filling alternative.
Best Side Dishes
- Japanese pickles (tsukemono): Adds tang and crunch to balance the mild broth.
- Grilled fish or yakitori chicken skewers: Complements the sesame miso base with smoky protein.
- Edamame or seaweed salad: Light, plant-based options that enhance nutrition.
- Tamago yaki (rolled omelet): A slightly sweet side that pairs well with savory dashi.
Seasonal & Dietary Pairings
- Summer menus: Combine with cold soba, iced green tea, or seasonal fruits like watermelon.
- Vegetarian/Vegan diets: Replace fish with tofu and serve with miso-glazed eggplant or sesame spinach.
- Light Japanese breakfast: Pair with rice, pickles, and roasted tea for a simple morning set.
Storage Instructions
Hiyajiru is best enjoyed fresh, but with proper storage you can safely prepare it ahead. Because it contains miso, fish, and fresh vegetables, following food safety guidelines is essential.
How to Store Hiyajiru
- Cool quickly: Let the soup base reach room temperature, then refrigerate within 1 hour.
- Separate components: Store broth, rice, and toppings (cucumber, shiso, tofu, fish) in separate airtight containers.
- Refrigeration: Keep the broth in the fridge for up to 2–3 days.
- Rice storage: Refrigerate steamed rice for 1–2 days or freeze in small portions for longer shelf life.
- Do not freeze the soup: Miso and cucumbers lose texture and flavor when frozen.
Food Safety Notes
- Always use clean utensils when serving to avoid bacterial growth.
- If the soup develops an off smell or cloudy appearance, discard immediately.
- For vegetarian or vegan Hiyajiru, tofu should be consumed within 2 days for best quality.
Handled with care, Hiyajiru keeps its refreshing flavor for a couple of days in the fridge, making it an ideal make-ahead cold miso soup for hot summer meals.
FAQ
What is the meaning of Hiyajiru?
Hiyajiru (冷や汁) literally means “chilled soup” in Japanese. It is a regional dish from Miyazaki Prefecture, made with miso, dashi, sesame, cucumber, and rice.
Is it okay to eat miso soup cold?
Yes, miso soup can be eaten cold. In fact, Hiyajiru is a cold miso soup created for hot weather.
What is the national soup of Japan?
While miso soup is considered Japan’s most common and representative soup, regional specialties like Hiyajiru.
Can Hiyajiru be made vegan?
Yes, Hiyajiru can be made vegan by replacing fish-based dashi with kombu (kelp) dashi or shiitake mushroom stock.
Final Thoughts
I love making Hiyajiru because it transforms simple ingredients into something unexpectedly refreshing. The nuttiness of sesame, the chill of cucumber, and the depth of miso create a harmony that feels both nourishing and light, exactly what I crave on long summer days.
For me, this recipe isn’t just about flavor, it’s about the ritual: toasting sesame until fragrant, flaking grilled salmon, and finally pouring the cold broth over warm rice. Each step slows me down and reminds me of the beauty of seasonal cooking and that’s why this dish always has a place in my kitchen.
