Miso is a renowned Japanese condiment that adds umami deliciousness to soups, sauces, salad dressing, sweets and so much more. This popular paste is super versatile, but a little goes a long way.
With most recipes only calling for a small amount you're likely to have a packet of miso that you've had for a while and find yourself asking questions like; How long does miso last in the fridge? Does it go bad? Is it safe to consume expired miso?
Whether you're deciding if you should keep the jar that's been lingering in your fridge for 6 months or simply looking for storage tips, you've landed in the right place. This article is packed with information on shelf life, signs of spoilage, storage suggestions and more.
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What is miso?
Miso is a fermented soybean product and a key ingredient in many Japanese recipes. It's made by fermenting soybeans, salt and a fungus called koji that is often cultivated from rice or barley.
Miso has a similar flavour profile to soy sauce with a distinctive salty and umami taste. There are more than 1000 varieties of miso paste with red and white being two the most commonly found types.
White miso paste has a light and slightly sweet taste due to its short fermentation time and higher proportion of grain to soybeans. It's often used in salad dressings and Japanese sweets like mochi and dango. Red miso's longer fermentation process gives it a stronger and saltier flavour and is used for making stews, soups and marinades.
What is miso used for?
Miso is most commonly known as the key ingredient in miso soup, which is eaten daily by many Japanese people. However, you can also use miso to add umami flavour to a range of other Japanese and Western dishes. These include soups like ramen, udon and nabe as well as salad dressings, marinades, and sauces for meat and vegetable dishes and stews.
Where can you buy miso?
It’s likely you’ll find Japanese miso in your local supermarket, but it's unlikely they'll stock more than one type. Visit an Asian Grocery store if you are looking for different types of miso pastes. They are likely to stock a range of brands and a larger selection.
How long does miso last?
The good news is that miso can last a really long time. Hikari Miso claims that most miso pastes will hold their quality for 1 year. An unopened package of miso paste will last up to a year when stored prooperly. Once opened, miso can last up to 6 months past its best-by date if it is stored well and does not become contaminated.
Does miso go bad?
The important thing to remember is that Miso paste is a 'preservative food' rather than a perishable product. It has a long shelf life, with most varieties lasting up to a year thanks to their high salt content. Miso does not rapidly go off like dairy and meat products. But like Worcester sauce and tabasco, its quality and flavour will gradually fade over time.
The expiration date indicates the time when the miso is past its best quality and it will slowly begin to decline when the use-by date has passed. You should consume it within its use-by date to enjoy it at its peak quality, but it’s very likely your miso paste will be safe to eat for a while longer.
Signs miso is bad
Look for signs of spoilage. Different colors and mould growth on the surface of the miso are a visual sign it has gone off. Temperature changes can cause a miso’s color to alter. If your miso is dark it's likely to have lost it's quality. When you store miso in a warm place the koji breaks down the raw ingredients and causes the color to darken and the flavour to change. You're more likely to see this when you store opened miso in a warm place. However, changes in temperature can also cause an unopened miso jar to deteriorate.
The best way to tell if miso has gone bad is to give it a good sniff. Good miso has a pleasantly salty and slightly sweet aroma whereas a bad miso is likely to have an off-putting strong smell and sour taste.
The best way to store miso
Storing miso at a low temperature is the best way to maintain its quality. However, if you are unable to store it in a cool dark place you can store it in a room temperature pantry or your kitchen cabinets.
The fridge is the best place to store opened fresh miso to prevent it from growing nasty bacteria. Cover the miso by keeping the lid on tight or using an airtight container or plastic wrap to store leftover miso paste that is no longer in its original packaging.
Top tip: Contamination is the most common cause of bad miso. Use clean spoons and other utensils to ensure that no unwanted bacteria find their way into your miso paste.
Can you freeze miso?
Freezing is a great way to store miso beyond its recommended use-by date. For best results (and for immediate use with no need to thaw) the temperature should stay above 25F and -5C. The miso will not freeze at this temperature and will maintain its paste-like texture and its umami taste will not fade.
You can freeze miso in its original packaging or use freezer bags. The best way to freeze small, individual portions is to use ice cube trays. Cover them or use trays with lids if you have them to avoid contamination.
Miso contains peptides produced during the fermentation process that help to maintain diverse and healthy levels of gut bacteria that benefit digestion and gut health. It contains aspergillus oryzae, a fungus and probiotic, which can reduce risk of bowel disease, cancer and other gut problems. High temperatures kill probiotics, so you should add miso at the end of the cooking process to ensure you reap the full benefits of its good bacteria.
Miso is a key ingredient in many Japanese meals including soup dishes like ramen, udon and nabe as well as sweet foods like mochi and dango. It's most well known for being the main ingredient for miso soup, made from combining miso paste with dashi stock and serving with tofu, wakame and green onions. Miso soup is a key dish in traditional Japanese breakfast and is eaten daily by many Japanese people.
A bowl of prepared packet or homemade miso soup will keep in the fridge for 2-3 days. Leave the soup to cool completely, cover and store it in the fridge. You can then reheat the refrigerated miso soup on the stove or in the microwave. If you are making a large batch with the intention of storing it and enjoying it later it is best to refrigerate the soup without the miso paste and add it at the end when you reheat it to preserve its taste and beneficial bacteria.
Miso is such a delicious and versatile condiment that when you discover the range of tasty, quick and easy recipes you can make with it, you'll be getting through it in no time and won't have to worry about it going bad again.
Miso eggplant/aubergine is tender, buttery and brimming with umami and takes just 15 minutes to make. If you're craving carbs, you should try my Spicy Miso Pasta where pasta and pancetta (or mushrooms) are tossed in a spicy miso-based egg sauce. Or if you love ramen, but are short on time, you can make this wholesome and easy chicken ramen on any day of the week.