Several years ago, I was gifted a small grafted sudachi tree by a friend. The bright green tree finally gave a bunch of sudachi fruits for the first time this year. It was incredibly exciting to harvest the citrus fruits and make today’s recipe, Cold Somen Noodles with Sudachi Lime. I’ve had a cold udon noodle dish with sudachi at a popular noodle shop, Tsurutontan (つるとんたん), in Japan many years ago. The broth was savory yet bursting with fresh fruity tartness, which was sublime to enjoy with soothing strands of noodle. Since then, it’s been my dream to recreate this refreshing dish at home. As San Francisco summer happens to be in September and we’ll have more fruits ready to be picked, this is the perfect time to live off this cold somen noodle all month long.
What is Sudachi?
Closely resembling a lime, sudachi (スダチ or 酢橘) is a small, round green citrus fruit of Japanese origin. Although the fruit is about the size of a golf ball, sudachi has a much higher juice content and a sour refreshing taste. Since sudachi is a muted variety of yuzu—another popular citrus fruit, we use this fruit for flavoring and garnishing in cooking. Most sudachi fruits come from Tokushima prefecture in Japan. You may find halved sudachi next to grilled sanma (pacific saury) or thinly sliced sudachi over chilled somen/udon noodles when you’re traveling in Japan.
Substitution for Sudachi
As sudachi is still rare here in the US or outside of Japan, you would be interested to see if limes can be a good substitute. I made the exact same recipe with lime and sudachi and did a side-by-side comparison. The good news is the flavors for sudachi and lime are quite similar and both pair well with this recipe. So a big yes, I would highly recommend using regular limes if you can’t find sudachi.
Creating Light-Color Noodle Soup with Shiro Dashi
The noodle soup broth is typically made with mentsuyu (or tsuyu)—the noodle soup base—that is often concentrated. We use this noodle soup base to make both hot and cold udon, soba, and somen noodle dishes. For my recipe, I opted shiro dashi, instead of typical mentsuyu, in order to create a lighter-color soup broth that helps spotlight the vibrant lime green of sudachi.
What’s Shiro Dashi?
Yamaki Kappo Shirodashi Versatile Dashi Base Marukin Shiro Dashi (Versatile Concentrate Dashi Base)
Or, you can make Homemade Shiro Dashi using my recipe below.
The Difference Between Mentsuyu and Shiro Dashi
Both mentsuyu and shiro dashi are pretty much the same, except that shiro dashi uses light-colored soy sauce called usukuchi shoyu (薄口醤油) or white soy sauce called shiro shoyu (白醤油). We use shiro dashi when we want to retain or highlight the original color of the food. The soup base is a much preferred choice for dishes such as Chawanmushi, Tamagoyaki, Oyakodon, Udon Noodle Soup, Clear Soup, and more!
How to Make Homemade Shiro Dashi
I highly recommend making your own Homemade Shiro Dashi at home! Store-bought shiro dashi is convenient but it tends to have preservatives and other ingredients we don’t need. The homemade version is very delicious and simple.
Ingredients for Sudachi Cold Somen
Dried somen noodles (or udon noodles) Shiro dashi – store-bought or homemade (kombu, katsuobushi, light-colored soy sauce, mirin, and salt) Sudachi (or lime)
How to Make Sudachi Cold Somen Noodles
Somen Noodle Cooking Tips
Remove wrappings from the bundles of somen. My favorite somen noodles (Ibonoito brand) require cooking for just 1½ minutes. It’s super fast! Therefore, all the noodles should go into the boiling water at the same time. Don’t overcook the somen noodles. The noodles are best when they are springy and have an elastic texture. The remaining heat will continue to cook the noodles, so it’s ok to slightly undercook and let them cool as soon as possible. Rinse the noodles well under cold running water. Using your hands, gently knead the noodles while rinsing them under cold running water. This helps to remove the excess oil from the noodles (the oil was used to make super thin noodles).
What to Serve with Sudachi Cold Somen Noodles
21 Popular Japanese Side Dishes Chikuwa Isobeage Pickled Watermelon Rind Karaage (Japanese Fried Chicken)
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