Learn everything you need to know about how to store dried seaweed and keep it fresh longer. In addition to proper storage methods, you'll also learn more about the expiry date and the #1 sign of spoilage. In Japan, we even know how to restore the crispiness of old dried seaweed. I'll teach you that trick too!
Author: Asami Goto is a bilingual Japanese food writer based in Tokyo. (edited and photos by Matt Eisenhauer)
Nori is just one type of seaweed that's eaten in Japan. For beginners, it's easy to get it confused with other kinds of edible seaweed such as wakame, konbu, and hijiki. On top of that, there are different varieties of nori and seasoned aji nori. Then there are the Korean versions, often seasoned with sesame oil, as well.
Dried seaweed (nori: 海苔) is a good source of dietary fiber. It's a healthy ingredient rich in minerals and nutrients. It can be used in a wide variety of Japanese dishes, for your health and your taste buds. You can even buy dried seaweed as a healthy snack at any convenience store in Japan.
Nori is well known as a common ingredient in classic Japanese cuisine such as sushi rolls and onigiri rice balls. Dried seaweed (乾燥海苔) is delicious eaten on its own and also delicious cooked. It adds a subtle umami taste of sea vegetables to your dish.
If you bought some nori and don't know what to do with it, you can read this guide to Japanese nori seaweed.
Because nori sheets are a dried and processed preserved food, they can be stored for a long period.
But do you know how long it can be stored?
How long does dried seaweed last?
The expiration date of dried seaweed generally ranges from 9 to 15 months. Just know that your seaweed may go bad sooner than the expiration date on the package if it's not stored correctly. This is true even if the original packaging is unopened.
Once opened, seaweed will lose its flavor and crisp texture due to moisture, even if it's stored correctly. After opening the package, it should be consumed as soon as possible, regardless of the expiration date on the package.
Many manufacturers recommend that the dried seaweed be eaten within approximately one month.
How do I store dried seaweed?
The best-case scenario is to eat it all as soon as possible after opening the package. Dried seaweed loses its flavor when exposed to air moisture. But if it must be stored, it needs to be kept inside a sealed plastic bag or container and stored in a cool, dry place.
The easiest way: If the bag of dried seaweed sheets you purchased has a resealable zipper, it's best to store it in the original bag. Remove as much air as possible. Done. Easy-peasy.
2nd easiest: If you bought a bag of dried seaweed without a zipper, you can transfer it to a seaweed storage bag with a specially designed zipper. A Ziploc freezer bag is the next best option.
3rd easiest: If you're going to keep your dried seaweed in an air-tight container, such as a canister or Tupperware food container, it should be stored with the desiccant that was enclosed in the original package. Close the lid or cover tightly as soon as you remove the dried seaweed from the container. Eat it as soon as possible before the flavor is lost.
Desiccants are those little square packets labeled 'DO NOT EAT' that remove air moisture from inside food packaging.
Sushi restaurants and izakaya in Japan use the above three options. Look at you-- you're already turning into a seaweed pro!
Note on refrigeration: Dried seaweed does not necessarily need to be stored in the refrigerator. It can be stored at room temperature for about 6 months as long as it's kept out of direct sunlight, high temperature, and high humidity.
There are advantages to keeping it in the fridge-- I'll go into more detail below.
The best way to keep the dried seaweed fresh
Dried seaweed is sensitive to heat, light, and humidity. That's why it's recommended to keep it in your refrigerator, where these conditions are less likely to exist. Before putting dried seaweed in the refrigerator after opening, first, wrap it in plastic wrap. Then, store it in a zipper storage bag or airtight container.
Unopened dried seaweed can be stored at room temperature as long as it is not exposed to direct sunlight and is kept away from high temperatures and humidity.
How about the freezer?
Also, unopened dried seaweed can be frozen to preserve its original crispy texture. To prevent condensation from occurring due to temperature differences, be sure to bring it to room temperature before opening.
Can you eat expired seaweed?
Dried seaweed can be eaten even after its expiration date as long as it has not gone bad. If it's stored properly, it's possible to eat dried seaweed that is one month to six months past its best-before date.
Dried seaweed that has passed its expiration date by more than one year is more likely to have gone bad even if stored properly. Avoid eating it even if it's cooked. It's recommended to eat it within the expiration date indicated on the package or label.
How to tell if dried seaweed has gone bad
Dried seaweed lasts for a long time and is said to be resistant to spoilage. Saying this, as it gets old, the original flavor, crispiness, and other qualities of the seaweed deteriorate. It's recommended to consume it as soon as possible to keep it tasting fresh.
There are a couple of telltale signs of dried seaweed that's gone bad.
These are the three signs of spoilage:
1. Unpleasant Odor
A bad smell is a clear sign your seaweed has gone bad. When dried seaweed becomes old, it may develop a fishy or sour smell. If you notice such a foul odor, dispose of it immediately.
2. Discolored
Dried seaweed can begin to turn purplish in color when exposed to moisture for an extended period. The discoloration of seaweed is difficult to see at first glance. But the difference in color can be clearly seen when you hold a sheet of seaweed up to a light or bright window. This phenomenon occurs because the pigment components decompose when the seaweed contains moisture. Discolored seaweed is most likely to have gone bad and should be discarded instead of eaten.
3. Mold
Basically, seaweed is a dry foodstuff which means mold does not easily grow on it. However, if it's not stored correctly after opening, mold can grow on it due to moisture absorption.
Tips on how to restore old seaweed to its crispy texture
Old, damp dried seaweed can easily be restored to its crispy state by frying it in a pan, roasting it over a stove flame, or allowing it to come into direct exposure to fire.
Simply fry the dried seaweed on both sides in a warm frying pan without oil to remove the moisture and restore the seaweed's crispy texture. If you're searing it directly over a stove flame, start about 20 cm away from the stove. Gradually move in closer to sear both sides.
To bring back the crispy texture, it's also recommended to toast it before eating. Toast one side of the seaweed for 6 to 8 seconds to get both sides crispy.
Microwave ovens can also be useful to dry out damp, limp seaweed and return it to its crispy texture. When using the microwave, first place the dried seaweed on a plate or microwave-safe cookie sheet. Warm it up at 500W for 30 seconds. Check the dried seaweed and heat it for 10 seconds more if needed. The seaweed is ready when the water has evaporated and the seaweed is crispy!
Recipes that use dried seaweed (nori)
Make a nutritious dish or snack with the unique flavor of this incredible, edible sea vegetable!
Temaki seaweed wraps (hand sushi wrapper)
Korean-style seaweed snacks with sesame seeds and almonds
Low-carb okra recipe (with less slimy texture)
Want to learn how to choose the right kind of dried seaweed at grocery stores, Asian markets, or online? Read the full guide to nori seaweed.
You'll find the best quality brands from Japan and South Korea.
ABOUT THE AUTHOR
Asami Goto Traditional Cooking Researcher（伝承料理研究家）
In order to globally communicate the appeal of traditional cooking methods handed down in each region of Japan, Asami conducts research on the tastes and characteristics of local ingredients, history, and local cuisine.
She is developing various Japanese recipes based on her knowledge of the role of dashi in Japanese cuisine and how to choose it, the colors and flavors of various misos, and how to make miso at home.
Asami is currently writing a recipe book for Japanese cuisine made by local Japanese families in Hawaii.