I’ve updated this very popular article a little bit and pushed it up from the archives, since it is the season for cold noodles now. I’ll also have a followup recipe soon for the perfect accompaniment to zaru soba. Originally published in May 2007.
Most of Japan gets very hot and humid in the summer. To combat the heat, a number of dishes meant to be eaten cold have been developed. One of the main cold summer dishes is cold noodles.
Soba noodles, made of soba (buckwheat), are available all year round but are really popular when the heat turns unbearable. As with other cold noodles, they are prepared in a way that may seem strange if you’re used to pasta and other Western-style noodles. Unlike pasta, most Japanese noodles, including soba, are rinsed rather vigorously in cold running water. This not only cools them down but gets rid of excess starch, which adversely affects the flavor of the noodles. Many recipes written in English omit this critical rinsing step: you don’t just plunge it in cold water, as many directions incorrectly state, but you actively wash the noodles. Once you’ve done this once, you will definitely notice the difference. I’ve given detailed instructions for this procedure below.
Dipped into a properly made sauce or soba tsuyu, with plenty of spicy condiments or yakumi, there’s nothing more refreshing to eat on a hot summer evening.
Note: zaru means basket - so these are soba served in a basket.
To serve 4 people
For the sauce (soba tsuyu):
Combine the two in a pan and bring up to a simmer. The less dashi you add the more intense the sauce will be, so add the dashi a little at a time, and start tasting after you’ve added about 1 1/2 cups: keep adding if it’s too strong. Simmer for 2-3 minutes, then let cool. You can do this a day ahead of time, and refrigerate the tsuyu.
Quick and easy version: Buy a bottle of concentrated tsuyu or mentsuyu, such as this one  from Kikkoman, and thin out with water.
Condiments, or yakumi:
Select at least one from:
Bring a large pot of water up to a boil. Unlike Italian pasta, you do not need to salt the water. Once it’s boiling, hold the noodles over the water and sprinkle them in strand by strand.
Once all the noodles are in, stir gently so that they are all immersed in the water.
Bring the water back up to a gentle boil, then lower the heat so that the water is just simmering. (This differs from the ‘rolling boil’ that’s recommended for pasta.) If the water threatens to boil over, add about 1/2 cup of cold water (but if you lower the heat to the gentle simmer, and have a big enough pot, this shouldn’t be necessary). Cook for about 7 to 8 minutes, or following the package directions (for thinner noodles 5 to 6 minutes may be enough. Test by eating a strand - it should be cooked through, not al dente, but not mushy either).
At this point, you may want to reserve some of the cooking water. This is called sobayu (そば湯), literally ‘hot soba water’, and many people like to add it to the remaining soba dipping sauce at the end of the meal to drink like soup!
Drain the noodles into a colander. Immediately return them to the pot and fill the pot with cold water. When you’re draining the hot water you may notice that it smells quite ‘floury’. This is what you want to get totally rid of.
If the noodles threaten to flood out over the pot, put the colander on the pot to hold the noodles down. Leave the water running for a while over the noodles.
Once the water and the noodle are cool, start to ‘wash’ the noodles. Take handfuls and gently swish and rub them in the water. Your goal is to wash off any trace of starchiness or gumminess on the noodles. When you’re done the water should run clear.
Make ready a flat sieve - a bamboo one is ideal and looks pretty. (You can use a nice looking colander instead, but flat sieves like this aren’t expensive - look in Asian markets.) Take a few strands of the noodles at a time.
Loop the strands onto the sieve to make a nice little bundle. This is one portion.
Allow for about 10-12 portions or so per person, if you’re using individual sieves. Arrange each bundle separately, to allow for easy pickup with chopsticks.
To serve the noodles: place a plate under the sieve or sieves to catch any drips. Put out small bowls filled with the condiments of your choice, which each diner can pick from. (Remember to put out small spoons and things if needed for the sesame seeds etc.)
The dipping containers can be anything that can hold about a cup or so of liquid. A rice bowl or a small soup bowl, or even a tumbler, can be used. Here I’ve used some small pudding molds that were a flea market find. (In Japan you can get special soba bowls or sobachoko.)
Fill each dipping bowl halfway with the cooled dipping sauce or soba tsuyu.
To eat, each person puts in the condiments of their choice, take a portion of the soba, and dips it in the sauce briefly - then, immediately eats the soba. Don’t let the noodle soak in the sauce or overload it with condiments, otherwise the delicate flavor of the soba will be overwhelmed.
At the end of the meal, you can add some of the reserve sobayu to the rest of your sauce (see above) to finish your meal.
The purest kind of soba noodle is made of 100% soba or buckwheat flour, plus water and salt. That’s really my favorite kind. There are other kinds of soba noodles though. Here I’ve used one made partly with konnyaku powder (which makes it quite sturdy, and supposedly lower-calorie).
Another popular kind of soba noodle has some green tea powder in it, which makes it a pleasant green in color. You don’t really taste the tea much though.
The best kind of soba noodle is freshly made (te-uchi), but this is a bit tricky…I haven’t actually mastered it yet. Maybe one day…
One of my favorite summer meals is cold soba, cold tofu or hiyayakko , some not-too-salty pickled cucumbers, and ice cold mugicha  to drink. Another favorite soba accompaniment is tempura, which can be dipped in the same sauce - for some reason tempura (battered fritters of vegetables, squid, shrimp and so on) seems to fit particularly well. But tempura is a rather hot and sweaty thing to make, so I usually stick to the cold tofu.