Shirasu しらす are tiny little white sardines. Known for its high content of calcium and protein, they are also packed with magnesium and zinc and relatively low in fats and sodium. Japanese like to give these to little babies who are starting on solids.
While some people like to eat them fresh and raw, the majority ones you find in the supermarkets have been processed beforehand. Shirasu are blanched and left out in the sun to dry naturally. The longer they are left under the sun, the harder they would become. So depending on the amount of time they sun-dried, they are named differently.
Nama-shirasu 生しらす: Require no prior process. Straight from sea. Serve raw and fresh on steamed rice with soya sauce or other seasonings.
Kamaage-shirasu 釜揚げしらす : Blanched in salted water then set aside to cool. Packed almost immediately thereafter. Retained 70-80% of water content, they are softer in texture.
Shirasu-hoshi しらす干し : Blanched in salted water and sun for a couple of hours. Retained 50-60% of water content and relatively soft in texture too.
Chirimen-jako ちりめんじゃこ: Blanched in salted water. Either dry naturally under the sun for at least half a day or in a dehydrator. Drier in texture with only 25-40% of water content.
You can check out some pictures here to see how the process looks like.
There is no particular way on how to choose Shirasu when buying – simply pick one with the longest expiry date. Compared to the rest, Chirimen-jako tends to be more expensive.
Since they have been blanched in salted water, you may want to give it a quick wash to remove excess salt (especially when giving to babies). Otherwise, simply just scoop them out from the food packaging and include them in your cooking directly.
They keep well in refrigerator for 3-7 days. Alternatively you can pack them into small portions with individual freezer bags, they could easily last for 3 weeks to a month in the freezer.
Shirasu has a high content of calcium, I often like to sprinkle a little in my dishes for my children. Because of their soft texture, they are also ideal for young children or for people with weak teeth. Currently I have 2 recipes using Chirimen-jako to share. Please check below.