This cold cucumber soup — oi naengguk — is very simple to make, but incredibly refreshing. It’s perfect for a hot day when you just want to cool off and not spend much time in the kitchen.

Oi Naengguk (Cold Cucumber Soup) — 오이 냉국


  • 2 small cucumbers (like Kirby cucumbers, which are used for pickling) OR 1/2 large, seedless, gourmet cucumber (like an English cucumber)*
  • 4 c. water
  • dash of Korean red pepper powder**
  • 2 Tbsp. soy sauce***
  • 2 Tbsp. white vinegar
  • 1 Tbsp. salt
  • 1 Tbsp. sesame seed
  • 1 Tbsp. chopped green onion (or scallions)

*The key is to look for a cucumber type with very small seeds. I used an English cucumber, which is longer and narrower than a regular cucumber and has smaller seeds. See photo above.

**To make this recipe gluten free, I used San-J Organic Tamari Gluten-Free Soy Sauce (available at Whole Foods or for $6.69 + shipping on

***You can find plastic bags or canisters of Korean red pepper powder (called gochugaru in Korean) at Asian grocery stores or on for about $13 a poundGochugaru‘s consistency is between a coarse powder and a fine flake, so it is sometimes called red pepper powder or hot pepper powder and sometimes called red chili flakes. See photo above.


  • Slice cucumbers into matchstick-shaped pieces.
  • Place cucumber pieces in bowl and marinate in sauce ingredients about 30 minutes.
  • Add 4 c. cold water to the cucumber mixture to make soup.
  • Season with red pepper powder and serve.

NOTE: I threw in some mushroom pieces since I had some left over. You can see them in the top photo. But the recipe does not call for mushrooms.

[Recipe from “Korean Cooking”, an out-of-print cookbook created by the Korean Institute of Minnesota.]