Garum

The most important contributor to umami in fish sauces is glutamate. The content of free glutamate can be very great, close to 1,400 mg per 100 g in Japanese ishiri and the Vietnamese nuoc mam tom cha, or a little more than in soy sauce. Usually, the salt content is also very high, all the way up to 25 percent, which is quite a bit more than the 14–18 percent found in soy sauce. The combination of umami and salt works synergistically to enhance the saltiness of fish sauce.