Amongst all the different types of Japanese sardines made into niboshi, hirako niboshi (平子煮干し) refers to niboshi made from maiwashi (マイワシ), or true sardines, the same sardines that are used for sushi. Whilst the highest quality iwashi for sushi are the richest ones with plentiful fat, the highest quality hirako niboshi is made from leaner smaller iwashi, as the high fat content can lead to overtly fishy aromas as well as the dashi going rancid quicker.
Suppliers we’ve talked to say that the ideal size of iwashi used for hirako niboshi is those less than 10cm in length, which then shrink considerably more as they dry out. You may also sometimes see this niboshi written as hirago niboshi (ひらご煮干し), with the ‘平’ word referring to its relatively compressed appearance of the dried fish.
Compared to the more famous katakuchi niboshi, hirako niboshi has a less sharp fish aroma and a rounder sardine characteristic which some say does not provide enough body for dashi alone. However, it does have a unique sweetness and therefore most chefs we have spoken to use this niboshi in a combination with other sardines rather than on its own.
For a more abstract description, people typically describe dashi made from hirako niboshi as assari (あっさり), which we go more indepth it on our series on rice.
Learn more about different ingredients that go into dashi and other types of niboshi.
