Mentsuyu is Japanese soup base used in soba and udon noodle dishes. It’s made from sake, mirin, soy sauce, kombu, and katsuobushi (dried bonito flakes).
There are two types of mentsuyu:
- Kaketsuyu (かけつゆ) – the sauce is poured hot over boiled noodles to make noodle soup
- Tsuketsuyu (つけつゆ) – “dipping soup” for chilled noodles
“Straight” or Dilute
Whenever the bottle says “straight” (ストレート), you do not need to dilute the sauce with water. However, many of the brands are concentrated and they require you to dilute the soup base with water depending on the use. Some says to dilute 3 x and some says 2 x.
In Japanese grocery stores, you will see different types of “soup base” for noodles. Some are for zaru soba like this (and it says “straight” ストレート, which means no diluting!).
For homemade Mentsuyu recipe, click here.