Japanese Dashi: The Textbook Example of Umami Synergy

The preparation of dashi starts by placing konbu in cold water. Most recipes stress that the water is then to be warmed up to just under the boiling point, at which time the seaweed is promptly removed. Under no circumstances is the water to boil, because that will result in a more bitter extract. There are, however, indications that having more control over the extraction process will yield a better outcome. Experiments have shown that a temperature of 60–65°C is optimal and that the best results are achieved by allowing the seaweed to steep at this temperature for an hour in a vacuum-sealed bag in a water bath. Some chefs have asserted that higher temperatures break down glutamate, but this is not correct, given that glutamic acid is stable up to at least 150°C.