Does Karo Syrup go Bad? (And How Long Can It Last)

Does Karo Syrup go Bad

Karo is corn syrup used in cooking and baking.  It helps baked goods hold moisture, adds sweetness, and maintain freshness.  Corn syrup is often used in Asian dishes to balance sweet and sour flavors.  Many use it as a glaze on hams, barbecued meats, or baked vegetables.  It comes in light, dark, reduced, calorie, and pancake syrup.  The dark corn syrup adds molasses for color and flavor.

Karo Corn Syrup can last indefinitely due to its very high sugar content. Though it has a “best-by” date, the texture or color may change past that date, but it may not necessarily go bad.  Factors affecting shelf life include storage method and if water gets in the syrup. Karo Syrup should be stored in the pantry at room temperature.

Let’s talk about Karo Syrups’ shelf life and how to store them best to ensure a long life.  Then, we’ll present some alternatives to use in place of Karo Syrup. Let’s dig in!

Does Karo Syrup Go Bad Over Time?

Stored properly, a bottle of Karo Syrup is safe to eat for an indefinite period of time.  If not stored correctly, Karo Syrup can lose its quality or if contaminants or water get into the bottle.  Light corn syrup may turn yellow as it ages, but this is normal and still safe to consume.

How Can you Tell if Karo Syrup has gone bad?

Light Karo Syrup may change color over time, and this is normal.  However, it may mean that the syrup is not at its peak flavor and texture.  If the syrup turns cloudy or hazy, mold may have started to grow.  Smell it and taste it.  It may affect your recipe if it seems off, and you don’t want to take that chance. It’s best to get a new bottle.

How to Properly Store Karo Syrup

  1. Store Karo Syrup in the pantry at room temperature.
  2. Make sure the lid is sealed after each use. Water, air, and other contaminants can cause changes in the syrup.
  3. Make sure you pour out of the bottle rather than stick a spoon into the bottle. This will reduce contaminants as well.  Touching the bottle rim or inside the lid with your fingers or mouth can introduce bacteria that can spoil the contents.
  4. Some people store their syrup in the fridge, but this is unnecessary. It will be thicker and more difficult to pour.
  5. Do not freeze Karo Syrup, as it will alter the texture of the syrup.

Does Karo Syrup Go Bad After Opening?

Karo Syrup can develop crystals around the edge from contact with contaminants from utensils or fingers.  While color changes are considered normal, if there is cloudiness or haze to the bottle, it may be mold formation.  While this will not make you sick, and you can remove the bad parts and continue to use the syrup, the quality might be a bit off.  The only guarantee of freshness is by the “best-by” date.  Trust your sense of smell and taste to determine whether to use or toss a bottle of Karo Syrup.

Can you Get Sick from Eating Old Karo Syrup?

Eating old Karo Syrup will not make you sick.  If you find mold or bad parts, it’s ok to scrape that part off and eat the rest with no ill effects.  It might be better to get a new bottle for freshness.

An interesting twist is that Karo Syrup was used in the past to relieve constipation.  Today, some people still use light corn syrup as the darker syrup has changed the recipe from the old days and may not be as effective.  Those looking for an organic alternative often steer away from Karo corn syrup, which is made from genetically modified corn.  Some doctors discourage using Karo Syrup to treat children due to possible bacteria levels and the tendency to affect dental health.

Does Karo Syrup Contain High Fructose Corn Syrup?

Karo Corn Syrup is derived from corn starch and can be used in place of some sugar in recipes creating a smoother texture.  High fructose corn syrup is corn syrup that is processed further and treated with enzymes to create fructose and glucose.  This tends to be a sweeter product.  Karo Corn Syrups do not contain any high fructose corn syrups; the pancake syrup does.

Alternatives to Karo Syrup

Bear in mind that a substitute might change the texture and flavor of your recipe.

Wholesome Sweeteners Organic Light Corn Syrup, 11.2 ozWholesome Sweeteners Organic Light Corn Syrup

Made from organic corn syrup, organic glucose syrup, vanilla, and salt, this is the kosher, vegan, gluten-free alternative if you want to avoid GMO ingredients.  You can use it for everything that calls for Karo Syrup.  When sealed and appropriately stored, pure, organic ingredients should last a good while, but they may spoil quicker when opened.

Steen's 100% Pure Cane Syrup, 16fl. ozSteen’s 100% Pure Cane Syrup

This is simple syrup in a bottle.  Made of pure sugarcane juice that is simmered into a thick syrup, it can be used in cooking.  The recommended shelf life is one year from the date of manufacture.  It will generally last at least two years unopened and one year after opening.  Store the same as all other syrups.

Lundberg Family Farms Organic Sweet Dreams Brown Rice Syrup

Lundberg Family Farms - Organic Sweet Dreams Brown Rice Syrup, Substitute Sweetener, Replaces Sugar, Honey, Corn Syrup, Non-GMO, Gluten-Free, USDA Certified Organic, Vegan, Kosher (21 oz) Marketed as a substitute for corn syrup, maple syrup, molasses, sugar, or honey, this syrup is non-GMO, gluten-free, organic, vegan, and kosher.  You can bake with it, use it to sweeten your coffee or tea, drizzle it over ice cream, or anything else you might use a liquid sweetener.  In general, brown rice syrup is suitable for a year from opening.

Agave in the Raw Organic Agave Nectar

AGAVE IN THE RAW, Organic Agave Sweetener, 18.5 OZ. Bottle (1 Pack) Non-GMO verified and certified organic; agave nectar is a substitute for many sweeteners as well.  It is vegan, kosher, and gluten-free.  Agave will last three years when stored at room temperature.  The syrup may turn darker if exposed to high temperatures, but the nectar will still be fine to consume.

Crown Maple Amber Color Maple Syrup

Crown Maple® Amber Color Rich Taste organic maple syrup 750ML (25 FL OZ) Maple Syrup can be used as a substitute for dark corn syrup in some recipes.  This one is 100% pure maple syrup and certified organic.  Maple syrup’s shelf life depends on its packaging.  Unopened glass bottles of maple syrup are good for up to four years.

Syrup in plastic containers has a shelf-life of two years.  After opening, it is safe to use for one year.  You can store it in the pantry or refrigerator, but make sure it’s tightly sealed.

Wholesome Organic Molasses

Wholesome Sweeteners - Organic Molasses Unsulphured - 32 oz. This organic and fair-trade certified molasses can be used as a substitute for Karo Syrup in some baking recipes.  The ingredient that makes Karo Syrup dark is molasses.  The shelf life of molasses is two years unopened and one year opened.  Store it in a cool, dark location and ensure the lid is on tight.  If it smells bad, toss it.

Nature Nate’s 100% Pure Organic Raw & Unfiltered Honey

Nature Nate's 100% Pure Organic, Raw & Unfiltered. Squeeze Bottle; Allnatural Sweetener, USDA Certified Organic, No Additives, Honey, 32 Oz Honey adds sweetness and texture.  It can be used as a substitute for Karo Syrup in some recipes.  Honey is rumored to last forever.  If it crystallizes in the jar, place the jar in hot water, and the honey will become liquid again. Honey should be stored properly in a sealed jar on the counter.

It doesn’t even have to be stored in a dark place.  Honey will often come with a best-buy date, which the manufacturer determines as peak freshness, but if you find some honey that you bought ages ago, it’s still good.

Anthony’s Organic Cane Sugar

Anthony's Organic Cane Sugar, 3 lb, Granulated, Gluten Free & Non GMOBoil the sugar and water to make a simple syrup if you need a thicker substitute.  Generally, use 1 ½ cups of sugar to ½ cup of water.  Boil until it is thick, stirring constantly.  You want to cook this gradually so it does not burn.

Then cool it off and use it in recipes.  Most sugar will work, but this is a gluten-free, non-GMO, vegan choice if you want to keep it organic.  Sugar lasts indefinitely in your pantry.  Store it in a tightly sealed container to keep out moisture and bugs.

Related Questions

Is Corn Syrup Healthy?

Sugar in any form will spike your blood sugar; too much sugar is not suitable for anyone.  Too much corn syrup (or any other sugar) can lead to weight gain, diabetes, hypertension, and a weak immune system.  It can also contribute to tooth decay and high cholesterol.  Corn Syrup is found in many processed foods such as pancake syrup, candies, and some soft drinks.  Karo Corn Syrup can be used in moderation, but it still has GMO corn and is processed.  High Fructose Corn Syrup is highly processed and should be avoided.

Can you make Corn Syrup from Scratch?

If you want corn syrup and want to control the ingredients, you can make it at home.  Basic ingredients are water, sugar, and corn kernels, and then a lot of time spent over the stove making a syrup.

Is Karo Syrup Gluten-free?

Karo syrup has no gluten-containing ingredients and is made in a facility that is free of gluten.   Karo Syrup does not have any other allergens.

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Choosing Nutrition Team

Here at Choosing Nutrition, our goal is to help people with making smarter food choices. Whether you're wondering about vegan, keto, paleo, or other diets, we'll help you determine which options fit your nutritional lifestyle. Our staff is composed of registered dieticians, nutritionists, and health-conscious individuals.

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