Dashi in Japanese refers to any stock used in cooking. The Dashi Kombu made by Matsumaeya is made from second year ma-kombu ("true bull kelp"), giving a very thick, full-bodied dashi. Dashi kombu is also delicious after cooking. Often in Japan, dashi kombu is used when making miso soup. The dashi kombu is served in the bowl with the miso, and eaten as such.
Using kombu for dashi is preferred over using smoked bonito flakes (hondashi) for the following reasons:
It is a vegetable, therefore suitable for vegan/vegetarian dishes
It is a 100% renewable resource. When harvested the root (stipe) remains, and then re-grows
It requires no pesticides, herbicides, fertilizers, or chemical additives
It can be matched to virtually any dish, whereas bonito can only been used in some dishes due to its inherently smoky taste.
If your area has particularly alkaline (hard) water then we recommend you use shredded dashi kombu in order to obtain the best flavor. When making a soup stock from dashi kombu we recommend 50 grams of dashi kombu to 5 liters of water (2 ounces to the gallon).