Refreshing and Easy Cold Korean Cucumber Soup for the Summer

This traditional Korean cold soup combines crisp cucumber and nutritious seaweed in an ice-cold, tangy broth that takes just 15 minutes to make—perfect for beating summer heat while staying hydrated and nourished.

Beat the summer heat the Korean way with this incredibly refreshing cold soup that has been cooling down Koreans for generations. Korean cucumber seaweed cold soup was traditionally enjoyed by field workers under the sizzling sun, who would drink it down like water for instant relief from hot weather. Today, this authentic naengguk (냉국) remains one of Korea’s most beloved summer dishes—and for good reason.

Unlike heavy summer meals that leave you feeling sluggish, this light soup provides instant cooling while delivering powerful hydration and nutrients. The combination of crunchy cucumber and silky seaweed creates fascinating textural contrasts, while the tangy, slightly sweet broth awakens your appetite even on the hottest days.

What If I Can’t Find Miyeok Seaweed?

Direct Substitutions with Ratios: Replace miyeok with wakame using a 1:1 ratio, but reduce soaking time to 5 minutes as wakame rehydrates faster. For a completely different but authentic variation, you can also use cherry tomatoes. While that is entirely different from seaweed, it also complements the soup!

Impact on Final Taste: Without seaweed, you lose the ocean umami and mineral complexity that makes this soup distinctive. The texture becomes less varied, relying solely on cucumber crunch.

DIY Alternatives: Create umami depth by adding a small piece of kombu (kelp) to the water for 10 minutes, then remove before serving. This provides oceanic flavor without seaweed texture.

Online Sourcing: Purchase dried miyeok from Amazon, H-Mart online, or Weee! delivery service. Brands like Ottogi offer pre-cut versions for convenience.

How Do I Know When This Dish Is Properly Made?

Visual Cues: The broth should be crystal clear with vibrant green seaweed and pale green cucumber pieces. Once soaked, miyeok turns green, plump, and ready to be eaten. Cloudy broth indicates over-salted cucumber or insufficient rinsing of seaweed.

Texture Indicators: Cucumber should maintain crisp bite while seaweed feels tender but not mushy. The crunchy cucumber together with slightly chewy and slippery seaweed creates interesting textural contrasts.

Flavor Balance: The soup should taste refreshingly tangy with subtle sweetness and clean oceanic notes. If too salty, add cold water; if too bland, add more vinegar and salt gradually.

Temperature Test: Add ice right before serving to keep the soup chilled during the meal. The soup should be cold enough to see your breath when drinking on a hot day.

What Should I Serve With This Dish?

Traditional Korean Meal Composition: Simply served with a bowl of steamed rice and a variety of banchan (side dishes). The cold soup replaces hot soup in summer Korean table settings.

Essential Banchan Pairings: Serve alongside kimchi, seasoned spinach (sigeumchi namul), and pickled radish (danmuji) to create textural and flavor variety. The warm rice contrasts beautifully with the ice-cold soup.

Modern Serving Suggestions: You can also mix somen noodles to make a Korean Cold Cucumber Noodle Soup. This transforms the side dish into a complete meal.

Beverage Pairings: Traditional barley tea (boricha) served at room temperature complements the soup without competing with its delicate flavors.

Nutritional Benefits & Cultural Context

Health Benefits of Key Ingredients

Cucumber Powerhouse: Cucumbers contain high amounts of water (about 96%) and are rich in vitamin K, vitamin A, and electrolytes. They contain more than 96% water and offer an easy and refreshing way to boost hydration.

Seaweed Superfood: Seaweed is especially rich in Vitamin K, with one serving offering up to 1/5th of the daily recommended value. It’s also high in both protein and fiber. Contains abundant iodine to reduce the swollen body and calcium to help build strong bones.

Cultural Significance in Korean Summer

Historical Context: The first historical record on naengguk appears in a poem written by Yi Kyu-bo (1168–1241), a high officer of the Goryeo period. This demonstrates the soup’s millennium-long tradition in Korean cuisine.

Modern Korean Lifestyle: Naengguk or “chilled soup” is a common type of food in Korea. Especially during the summer when it’s humid, people don’t like turning on their stoves and just want a quick thirst-quenching soup.

Recipe Troubleshooting Guide

Common Problems and Solutions

Watery, Flavorless Broth: This happens when cucumbers release too much water. Next time, salt cucumber pieces lightly, let drain for 10 minutes, then rinse and pat dry before adding to soup.

Overpowering Seaweed Taste: If you add too much seaweed or leave the seaweed too long in the soup, the seaweed flavor may be too strong. Reduce seaweed quantity or add it just before serving.

Diluted Flavor After Adding Ice: Season on the aggressive side as ice will melt and dilute the soup. Always taste and adjust seasonings after adding ice cubes.

Storage and Reheating

Refrigerator Storage: It can be stored in the fridge for a few days. Store without ice cubes and add fresh ice when serving.

Batch Cooking Tips: You can make ahead up to this point several hours or a day before, if desired. Prepare everything except adding water and final seasoning.

Texture Maintenance: Store cucumber and seaweed separately if making more than 1 day ahead, as cucumber will release water over time.

Seasonal Cooking Tips

Summer Optimization

Beat the Heat Strategy: Oi Naeng Guk is enjoyed as a substitute for hot soups in the summer so serve it in small individual soup or cereal bowls. Serve in pre-chilled bowls for maximum cooling effect.

Hydration Benefits: Made with julienned cucumbers, icy broth, and sometimes vinegar, oi naengguk is ultra-refreshing and especially great when you need to hydrate and snack at the same time.

Equipment Recommendations

Essential Tools: Sharp mandoline for consistent cucumber cuts, fine-mesh strainer for seaweed preparation, and large mixing bowl for easy combination.

Korean Kitchen Equipment: Traditional Korean stone or ceramic bowls enhance the eating experience and maintain cold temperature longer than regular bowls.