Oyster sauce is a well-loved cooking ingredient that helps to quickly build flavor in a stir fry. It is a delightful combination of caramelized oyster juices, sugar and salt; some oyster sauces are also made with soy sauce. It is a dark syrupy sauce with a sweet but salty taste.
Despite the fact that it’s made from mainly seafood, it does not have the same fishy flavor as fish sauce. Because oyster sauce is fermented, a common question is whether oyster sauce goes bad, keep reading to find out.
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Does Oyster Sauce Go Bad?
Yes, but when will depend on the brand, the expiration date printed on the bottle, and the method in which you choose to store it.
As mentioned, oyster sauce is made from oysters, spices and sugar. Due to the type of ingredients used, it is inevitable that oyster sauce will eventually expire.
However, if it is stored properly, oyster sauce can last for quite some time as you will shortly discover.
How long Does Oyster Sauce Last?
First, it’s important to determine the actual expiration date because not all dates on food labels refer to this. According to the U.S. Department of Agriculture (USDA), there are four common food label dates, these include the following:
- Best if used by: The best date to use the product before the flavor starts to decline.
- Coded or closed by: The letters and numbers used by the manufacturer to note the time and date the product was packed.
- Sell-by: The date when stores are no longer able to sell the product.
- Use by: This is the last day that the product will be at its best quality.
As you have probably figured out, none of these are expiration dates, and neither do they give any indication as to whether the products are safe to consume.
According to the Food and Drug Administration, it is perfectly okay for manufactures to sell food past these dates. With that being said, to be on the safe side, the best advice is not to consume any foods that are past these dates.
Ordinarily, how long oyster sauce lasts depends on the brand; but in general, if a bottle has not been opened, you can expect it to last between 18-24 months.
An expiration date is often not the deciding factor as to whether Oyster sauce has gone bad or not (we will discuss this in a later section). However, if only a couple of weeks have passed since the expiration date, it is probably still safe to use.
On the other hand, once the oyster sauce has been opened, you will need to store it properly to ensure it lasts until the expiration date. Once opened, it’s advised that you use the contents within three to six months.
However, reports state that some of the more high-quality brands of oyster sauce last for a year or more once the bottle has been opened. Nevertheless, if you are unsure about the brand and don’t want to take the risk, it’s best you finish the contents of the bottle within six months.
Alternatively, when oyster sauce is kept in the fridge after it has been opened, you can expect it to last for up to two years.
|Opened Oyster Sauce||3 – 6 months||
|Unopened Oyster Sauce||–||
18 – 24 months
5 Tips to Tell If Oyster Sauce Has Gone Bad
Oyster sauce will go bad if you haven’t stored it properly or if you have had it for longer than the time frames mentioned above. Here are 5 tips to tell if your oyster sauce has gone bad:
- Mold: Despite the fact that oyster sauce is a liquid, it can get moldy. Unlike solid food, the mold will sit floating on top of the liquid and you will see it as soon as you open the bottle. As tempting as it might be, don’t think you can pour out, or scoop off the mold from the top and use it anyway. Once mold has found its way into the bottle, you can guarantee its expired.
- Color and Flavor: When oyster sauce has been kept for a long period of time, the process of oxidation will cause it to become stronger in flavor and darker in color.
- Taste: Oyster sauce is not designed to eat alone; it is used to compliment other foods. However, if it tastes sour or bitter, throw the bottle in the trash.
- Smell: Oyster sauce should have a fresh, tantalizing aroma, if it smells putrid or moldy, throw it away.
- Consistency: Oyster sauce should be of a thick consistency; if you’ve had it for longer than the expiration date, pour a bit out and check whether the thickness still remains. If the consistency is like water, get rid of it.
4 Tips to Store Oyster Sauce
Oyster sauce is no different to other condiments, the way it is processed makes it shelf stable. This means they have a long shelf life even after they’ve been opened. Here are four tips on how to store oyster sauce:
- Keep Sealed: Depending on the type of oyster sauce you purchase; it will typically come in a jar with a screw top or a flip lid. Whichever one you get, make sure you secure the lid properly before storing it. One of the main reasons why its so important to seal your oyster sauce before storing is that it accelerates the spread of bacteria, and bacteria overgrowth is one of the most common causes of food poisoning even when the food hasn’t reached its sell-by date.
- Away From Direct Sunlight: If you are not going to keep your oyster sauce in the fridge, make sure it is kept out of direct sunlight. One of the main reasons for this is that bacteria grows quickly on foods when they are exposed to temperatures between 41 to 135 degrees. This is referred to as ‘the temperature danger zone.’ Keeping oyster sauce away from direct sunlight is especially true if you live in a hot country.
- Cool and Dark: To avoid exposing oyster sauce to direct sunlight, it’s best that you store it in a cool dark place. You can either keep it in the pantry, or a cupboard in the kitchen.
- Keep it in the Fridge: Despite the fact that it’s not necessary to keep oyster sauce in the fridge, it does help to keep the flavor longer if you are planning on keeping it for some time.
When it comes to storing oyster sauce, the best advice is to follow the manufacturers’ guidelines. Depending on the brand, some will tell you to refrigerate it once opened and some won’t.
The Risk of Consuming Expired Oyster Sauce?
Consuming oyster sauce a couple of weeks after the expiration date isn’t going to harm you.
However, if mold has developed and there is an offensive smell coming from the bottle, you might have a problem.
Sometimes eating food past the expiration date can lead to food poisoning, but symptoms will vary depending on the type of bacteria you have been infected with.
In general, you can expect the following if you get food poisoning from expired oyster sauce:
- Mild fever
- Loss of appetite
- Abdominal cramps
The above symptoms are not life threatening, and you can probably treat the food poisoning at home with over the counter medication.
However, if you experience any of the following symptoms, it is essential that you book an appointment with your healthcare provider immediately:
- Bloody urine
- Dehydration causing a dry mouth and the inability to keep fluids down
- Difficulty speaking or seeing
- A fever of more than 101.5 degrees F
- Diarrhea lasting longer than three days
Can You Freeze Oyster Sauce?
Unfortunately, oyster sauce does not freeze at all. The reason for this is that it contains a high salt content. When particles such as chloride ions and sodium have been dissolved in a liquid, it no longer freezes at a high temperature.
Not to get too scientific here, but this is referred to as “freezing point depression” and it happens when any particles are dissolved in a liquid, it doesn’t have to be salt.
Basically, the particles do not allow the freezing process to take place, this is one of the reasons why salt is used to dissolve ice on the roads.
Additionally, oyster sauce originates from the soy sauce family and it is fermented. When a product is fermented, it produces the ethanol found in alcohol which also reduces the freezing point.
Oyster sauce is a delicious addition to any meal, and depending on the brand, it can be expensive. Therefore, you want to keep it fresh for as long as possible.
additionally, you don’t want to make the mistake of eating gone off oyster sauce, so make sure you take the necessary precautions of looking inside the bottle to check for any mold, and smelling it before adding the sauce to your food.