Cold Udon Noodles (Zaru Udon) ざるうどん

3 days ago 11

A plate of chilled udon noodles on a bamboo mat, garnished with green maple leaves, served with dipping sauce, wasabi, green onions, ginger, and sesame seeds on a rustic wooden table.

When the summer weather gets hot and you don’t have much of an appetite, try this delicious Cold Udon Noodles (Zaru Udon) recipe. Classic fare during the hot and humid summers in Japan, these chilled noodles are so refreshing and simple to prepare, especially when you don’t feel like cooking! I’ll show you how to make the savory dipping sauce two ways—either from scratch or with store-bought noodle soup base.

If you love udon, try my Beef Udon, Yaki Udon (Stir-Fried Udon Noodles), and Kitsune Udon recipes next!

Table of Contents

A plate of chilled udon noodles served on a bamboo mat with ice cubes, garnished with maple leaves. Sides of sliced green onions, wasabi, shredded nori, and dipping sauce are arranged around the plate on a wooden table.

What is Cold Udon Noodles (Zaru Udon)?

Cold udon noodles (zaru udon, ざるうどん) is a dish that we serve in Japan during the summer months when the weather is hot and humid. The chilled noodles taste refreshing when served with savory mentsuyu dipping sauce and toppings like green onions, ginger, and wasabi. This dish is the cold version of Kake Udon that’s served hot with dashi broth and sliced green onions on top.

Namiko Hirasawa Chen

Why I Love This Recipe

Perfect summertime lunch that’s cool and refreshing.
Light and savory flavors to stimulate your appetite on a hot day.
Easy to make when you’re not in the mood to cook.

A plate of chilled udon noodles on a bamboo mat with ice cubes, garnished with a green maple leaf. Wooden chopsticks rest on the plate, and bowls of dipping sauce and sesame seeds are nearby on a wooden table.

Ingredients for Cold Udon Noodles (Zaru Udon)

udon noodles – frozen
Homemade dipping sauce (tsuyu):
- dashi (Japanese soup stock) – Use a dashi packet or make Awase Dashi or Vegan Dashi from scratch
- mirin
- soy sauce
- sugar
Condiments:
- green onion/scallion
- ginger
- wasabi (optional)
(Optional) Quick dipping sauce:
- water and mentsuyu (concentrated noodle soup base) – bottled
- kombu (dried kelp)
- katsuobushi (dried bonito flakes)

Find the printable recipe with measurements below.

Jump to Recipe

A plate of cold udon noodles served on a bamboo mat with ice cubes, garnished with green maple leaves. Chopsticks are placed on the side, and small dishes surround the main plate on a wooden table.

How to Make Cold Udon Noodles (Zaru Udon)

Dipping Sauce

Make the dipping sauce. Simmer dashi stock, sugar, and mirin in a small saucepan over medium heat. Then add soy sauce. Cool completely.

A hand pours a dark liquid from a small glass bowl into a saucepan with a light-colored liquid, on a stovetop.

A glass measuring cup filled with dark liquid is placed in a metal bowl with ice cubes on a wooden surface, cooling the liquid.

Noodles

Heat the udon noodles. Place the frozen noodles in a large pot of boiling water until heated through. If you’re using dried udon noodles, cook according to the package instructions.

A pot of simmering clear broth is being stirred with a wooden spoon on a stovetop. The liquid is light golden in color, with bubbles forming as it heats.

Rinse and cool. Drain the noodles in a sieve and rinse under cold water. Then, add the noodles to an ice bath for 30–60 seconds, then drain. If you chill too long, the noodles become too firm.

A hand rinsing cooked udon noodles under running water in a metal colander placed in a sink.

A metal colander contains cooked udon noodles with ice cubes, sitting on a sink rack, likely being cooled or rinsed.

Condiments

Prepare the condiments. Thinly slice the green onion and grate the ginger. Put them on individual small plates.

A close-up of hands slicing green onions on a wooden cutting board with a knife. Thin, round slices of the green onion are scattered on the board.

Assemble

Drain and divide the chilled noodles and ice cubes onto individual plates. Pour the sauce into individual cups. Serve with condiments on the side. Add green onion, ginger, and optional wasabi to the sauce, dip the noodles, and enjoy.

A person arranges cooked udon noodles on a bamboo mat placed on a round black plate.

Nami’s Recipe Tips

Make the tsuyu from scratch – I recommend making homemade dipping sauce for the best flavor, but you can use store-bought mentsuyu to save time.
Cool the sauce – After simmering it on the stove, make sure to cool down your dipping sauce completely before serving. I rest the pitcher of dipping sauce in a bowl of ice to chill it.
Use frozen udon – I recommend my favorite frozen Sanuki udon from the Japanese market. Alternatively, Hime Dried Udon is a decent dried substitute from Amazon. If you have the time, Homemade Udon Noodles are delicious!
Rinse the noodles – Run the hot noodles under cold tap water while tossing them with your hands like you’re washing clothes. This cools them down and removes any excess starch.
Chill briefly – Add the rinsed and cooled noodles to an ice bath with plenty of ice cubes for 30–60 seconds, then drain. If you chill too long, the noodles become too firm.
Serve with ice cubes – Add some of the ice cubes to the udon plates to keep the noodles cold and super refreshing.

Variations and Customizations

Get creative with your toppings. Also, the Japanese enjoy other cool udon dishes during the summertime. Here are some popular variations that you can try.

Extra toppings like shredded nori, tenkasu (tempura scraps), julienned shiso, and toasted sesame seeds
Cold Tanuki Udon with tempura scraps, tomatoes, cucumbers, wakame seaweed, and boiled egg
Cold Natto Udon with fermented soybeans has the delightful texture of Japanese neba neba (ネバネバ, slimy) foods
Cold Curry Udon in chilled curry soup with sliced pork and summertime vegetables

A white bowl containing chilled udon noodles, tenkasu, julienned cucumber, boiled egg, wakame seaweed, and grated onion, along with savory noodle soup.

A white bowl containing cold curry udon with sliced pork, boiled egg, and fresh vegetables.

What to Serve with Cold Udon Noodles (Zaru Udon)

Tempura – Learn How to Make the Best Tempura for a classic pairing called tenzaru udon.
Salad – Green salad drizzled with Carrot Ginger Dressing is cooling and refreshing.
Japanese barley tea – Chilled Mugicha is a summertime favorite drink for adults and kids alike.

A plate containing assorted vegetable tempura.

Carrot ginger dressing drizzled on the refreshing iceberg lettuce and cucumber slices.

Storage Tips

To store: Store leftover dipping sauce in a clean, airtight container in the fridge for up to a month. I recommend cooking the udon noodles just before serving.

Gather all the ingredients. Here, I show what you'll need to make homemade tsuyu (noodle dipping sauce).
To prepare a quick dipping sauce instead using bottled mentsuyu (concentrated noodle soup base), see my optional recipe at the end.

To Make the Homemade Dipping Sauce (Tsuyu)

Add ⅔ cup dashi (Japanese soup stock), 2 Tbsp mirin, and 1 tsp sugar to a small saucepan. Bring it to a simmer over medium heat and stir to dissolve.
Next, add 2 Tbsp soy sauce. Bring it back to a simmer, then turn off the heat. Transfer to a heat-resistant container or serving pitcher and set in a bowl of ice to let cool (you can make it ahead and keep in the fridge).

To Prepare the Noodles

Bring a large pot of water to a boil. Add 2 servings udon noodles (frozen; no need to defrost) and boil for 1 minute to heat through. Nami's Tip: I use my favorite frozen Sanuki udon from the Japanese market. Alternatively, Hime Dried Udon is a decent option from Amazon; cook according to package directions.
Drain in a sieve. Thoroughly rinse off the udon's starch under running water until they’re no longer slippery. Once cool, place the noodles in an ice bath to chill for 30–60 seconds (if you chill too long, the noodles become too firm).

To Prepare the Condiments

Cut 1 green onion/scallion into thin slices. Peel and grate ½ inch ginger; I use a ceramic grater. Put sliced green onion, grated ginger, and optional wasabi on individual small plates.

To Serve

Drain the chilled udon noodles well. Divide onto individual serving plates along with a few of the ice cubes. Divide the cooled tsuyu sauce into individual dipping cups. Serve the cold udon noodles and dipping sauce. Add the condiments directly to the dipping sauce and enjoy.

To Store

Store leftover dipping sauce in a clean, airtight container in the refrigerator for up to a week. I recommend cooking the udon noodles just before serving.

(Optional) To Make the Quick Dipping Sauce (4 servings)

Add ½ cup mentsuyu (concentrated noodle soup base), 1 piece kombu (dried kelp), and ½ cup katsuobushi (dried bonito flakes) to a measuring cup or container. Let it steep for at least 10 minutes or overnight in the fridge. Drain the mentsuyu through a sieve (discard or repurpose the kombu and katsuobushi). To use: Dilute with 1½ cups water, then serve into individual dipping cups.
Nami's Tip: The mentsuyu brand I use is concentrated 3 times for cold noodle dipping sauce (men no tsuketsuyu). The dilution ratio is one part mentsuyu to three parts water (1 : 3). Follow your bottle's dilution instructions, as each brand is different. If you have “straight” mentsuyu, use it as is without diluting.