Quick Answer
Cornmeal can last 5-10 years in properly sealed mylar bags stored in a cool, dry place. The key to long term storage is minimizing air exposure and keeping moisture out. With the right storage conditions, cornmeal’s shelf life can be significantly extended in mylar bags versus storing it in the paper packaging from the store.
How Long Does Cornmeal Last in the Pantry?
When stored properly in a pantry, cornmeal will typically last 6-12 months past the “best by” date on the package. The exact shelf life depends on the type of cornmeal:
- Degermed cornmeal: 6-8 months
- Whole grain cornmeal: 9-12 months
The main factors that impact cornmeal’s shelf life are exposure to air, light, moisture, and temperature fluctuations. Over time, the oils in cornmeal can go rancid when exposed to excess air. Moisture causes mold growth, while light and heat accelerate the rate of oxidation.
Storing cornmeal in an airtight container in a cool, dry place helps prolong its freshness. But eventually the oils will still oxidize and the cornmeal will take on a stale flavor and powdery texture. At that point, it’s time to toss the cornmeal and get a fresh bag.
Why Store Cornmeal in Mylar Bags?
Mylar bags provide much better long term storage for cornmeal compared to paper bags or plastic containers. Here are the key benefits of using mylar bags:
- Airtight seal – Mylar bags can be sealed completely airtight with an oxygen absorber inside. This prevents air exposure which is the main factor in cornmeal going rancid.
- Moisture barrier – Mylar is moisture proof, blocking external humidity from getting in.
- Light protection – Mylar is impermeable to light, which slows oxidation.
- Rodent resistant – The durable mylar material means rodents cannot chew through it.
By keeping air, light, and moisture away from the cornmeal, mylar bags effectively put the cornmeal in a state of suspended animation. It remains fresher for years if stored in a cool place.
How to Store Cornmeal in Mylar Bags
To maximize cornmeal’s shelf life in mylar bags, follow these steps:
- Purchase high quality mylar bags designed for long term food storage. Getbags with a thick 3-7 mil thickness.
- Include an oxygen absorber in the bag to remove oxygen. Use one rated for at least 100cc of oxygen absorption.
- Load the mylar bag with cornmeal. Don’t fill more than 75% full toallow room for the oxygen absorber to work.
- Use a hot iron or mylar bag sealer to create an airtight seal across the mouth of the filled bag. Test the seal carefully.
- Pack the sealed mylar bags into a plastic drum or food-grade bucket to protect against punctures.
- Store the bucket in a cool, dry place like a basement or cellar. The ideal temperature is below 68°F.
As long as the cornmeal stays sealed in the mylar with an oxygen absorber, it will stay fresh for many years. Let’s take a look at how long it keeps in ideal conditions…
How Long Does Cornmeal Last in Mylar Bags?
With optimal mylar bag storage, cornmeal can realistically last 5-10 years past the original purchase date.
The shelf life depends somewhat on the variety and grind size:
| Type of Cornmeal | Shelf Life in Mylar Bags |
|---|---|
| Degermed yellow cornmeal | 5-7 years |
| Stone ground whole grain cornmeal | 7-10 years |
Degermed cornmeal lasts a little less time since it contains more oil that can oxidize. But keeping it sealed in an oxygen-free mylar bag gives it 5+ extra years beyond the normal pantry life.
The coarser particles and lower processing of stone ground cornmeal help it maintain freshness longer in storage. Properly stored in mylar, whole grain cornmeal can still be good for up to a decade.
Note that these times are for maximum quality retention. The cornmeal will still be safe to eat long after it loses peak freshness. You just may notice some changes in flavor, color, and texture the longer it is stored.
How To Tell if Cornmeal Has Gone Bad in Mylar Bags
It’s hard to visually inspect cornmeal through the opaque mylar packaging. Here are some signs that the cornmeal has spoiled or degraded in quality:
- Oxygen absorber is no longer functional – If the absorber is still working, it will be hard and dry. If it is soft or has turned color, that indicates air has gotten inside and spoiled the cornmeal.
- Bag has lost vacuum – Check if the mylar bag still cling tightly to the cornmeal. Loose bag with air inside means air exposure.
- Off smell – When first opened, it should smell fresh. A rancid or musty odor indicates spoilage.
- Change in texture – Spoiled cornmeal may be powdery instead of granular, due to oxidation.
- Damp clumping – Any moisture in the bag will cause cornmeal to clump together when dry.
- Color changes – More yellow or brown hues indicate oxidation of the cornmeal oils.
Any of these are signs that the quality has degraded. Taste a small sample of the suspect cornmeal to determine if the flavor is off. If it smells or tastes bad, the safest option is to throw it away.
You can also extend the shelf life by repackaging cornmeal into new mylar bags every 2-3 years. This replaces the oxygen absorbers and ensures a good seal.
Does Cornmeal Go Bad?
Cornmeal does not actually “go bad” in the sense of being unsafe to eat. As a dry, shelf-stable product, cornmeal is very low risk for developing harmful bacteria or toxins.
However, over time the quality will degrade:
– Fats will oxidize causing rancid taste and smell
– Moisture allows mold growth
– Nutrients like vitamins A and E deteriorate
– Color fades from vibrant yellow to pale yellow-brown
– Texture becomes more powdery/less grainy
While old cornmeal won’t make you sick, the stale and bland flavor means it’s best to throw it out and start fresh. Storing in mylar bags slows the rate of quality degradation significantly. But no storage method lasts forever.
Cornmeal Storage Tips
To maximize the shelf life of cornmeal once opened, keep these tips in mind:
- Use mylar bags – Mylar bags with oxygen absorbers are ideal for long term storage of cornmeal.
- Freeze for short term – Freezing prevents oxidation and extends life for a few months.
- Cool and dry – Store cornmeal in a cool cupboard away from heat, moisture, and sunlight.
- No refrigeration – The fridge introduces unwanted moisture. Leave sealed mylar bags in a cool basement instead.
- Rotate stock – Use oldest cornmeal first and replace with fresh every year or two.
- Check for bugs – Inspect for any signs of insects which can contaminate cornmeal.
Proper storage practices allow you to keep cornmeal on hand for years to come. Mylar bags provide the best environment for maximizing its shelf life.
Frequently Asked Questions
Does cornmeal need to be refrigerated?
No, cornmeal should not be refrigerated. The cold, humid environment of the fridge can cause moisture to get into the cornmeal and accelerate spoilage. Simply store cornmeal in a cool, dry pantry or cupboard in an airtight container. The freezer can extend life short term but is not needed for everyday storage.
How long does cornmeal last at room temperature?
Properly stored in a pantry, cornmeal will last 6-12 months past the printed expiration date before quality degradation occurs. Whole grain cornmeal keeps a little longer, around 9-12 months. Degermed cornmeal may start losing freshness around 6-8 months.
Can you freeze cornmeal?
Yes, you can safely freeze cornmeal for short term storage up to 3-6 months. Place it in an airtight freezer bag or container, squeezing out excess air. This prevents condensation from forming that can lead to clumping when thawed. It extends shelf life by slowing oxidation.
What happens if you eat cornmeal that has gone bad?
Eating spoiled cornmeal does not pose serious health risks. Because it is a dry, low moisture food, it is very unlikely to grow harmful bacteria or mold. The main issue with spoiled cornmeal is an unpleasant taste and stale texture. At worst, it may cause brief nausea or upset stomach if enough rancid oils or mold are present.
How can you tell if cornmeal is spoiled?
Signs that cornmeal has spoiled include a rancid smell, powdery or clumpy texture, color changes from yellow to brown or gray, presence of moisture or condensation, and dull or faded appearance. Taste a small amount to check for a stale, bitter flavor. Any of these indicate it is past its prime and best discarded.
Conclusion
With proper long term storage using mylar bags and oxygen absorbers, cornmeal can last 5-10 years past its original purchase date. This significantly extends the typical pantry life of 6-12 months. The airtight, moisture-proof seal of mylar bags prevents air exposure and humidity that leads to quicker spoilage of cornmeal. While it won’t spoil in a way that makes it unsafe, stale and rancid cornmeal should be discarded once it loses optimal flavor and texture. Following best practices for cornmeal storage allows you to keep it fresh and ready to use for all your favorite recipes.
