Can I Can Corn? Is It Safe and How Do I Do It?
The answer is yes, you can can corn at home, but it’s absolutely critical to use a pressure canner due to corn’s low acidity, which makes it vulnerable to botulism if improperly processed.
Introduction: The Allure of Home-Canned Corn
Few things rival the taste of freshly harvested corn, bursting with summer sweetness. Preserving this flavor through home canning allows you to enjoy a taste of sunshine throughout the year. But canning corn isn’t as simple as jam-making. Due to its low acidity, improper canning can lead to serious health risks, namely botulism. This article will guide you through the safe and proper methods for canning corn at home, ensuring a delicious and safe final product.
The Botulism Threat: Why Pressure Canning is Essential
Botulism, caused by the bacterium Clostridium botulinum, thrives in low-oxygen, low-acid environments, such as improperly canned foods. Corn falls squarely into this category. The bacteria produce a potent neurotoxin that can cause paralysis and even death. Boiling water bath canning, suitable for high-acid foods like jams and pickles, does not reach a high enough temperature to kill Clostridium botulinum spores in low-acid foods. Only a pressure canner can achieve the necessary temperature (240°F/116°C) to eliminate these spores, rendering your canned corn safe for consumption.
Preparing Your Corn: From Field to Jar
The quality of your canned corn depends heavily on the quality of the corn you start with. Use fresh, mature ears, ideally picked the same day you plan to can them.
- Shucking: Remove the husks and silks.
- Cleaning: Thoroughly wash the ears to remove any dirt or debris.
- Blanching: Blanching stops enzyme action, which helps preserve color, flavor, and nutrients.
- Water Blanching: Submerge the corn in boiling water for 3 minutes (for cut corn) or 4 minutes (for whole kernel corn).
- Steam Blanching: Steam corn for 5 minutes (cut corn) or 6 minutes (whole kernel corn).
- Cutting (Optional): If you prefer cut corn, use a sharp knife to slice the kernels from the cob, about halfway down.
Canning Methods: Raw Pack vs. Hot Pack
There are two main methods for packing corn into jars: raw pack and hot pack.
- Raw Pack: The corn is packed raw into the jars. This method is faster but may result in greater shrinkage during processing.
- Hot Pack: The blanched corn is heated in boiling water for a few minutes before being packed into jars. This method reduces shrinkage and often results in a better vacuum seal.
Step-by-Step Guide: Pressure Canning Corn
This guide assumes you are using a dial-gauge pressure canner. Always consult your canner’s manual for specific instructions. If using a weighted-gauge pressure canner, refer to its specific pressure and processing times.
Prepare Jars and Lids: Wash jars in hot, soapy water and rinse thoroughly. Sterilize jars by boiling them for 10 minutes. Keep jars hot until ready to use. Heat lids in simmering water (do not boil).
Pack Jars: Pack the corn into hot, sterilized jars, leaving 1 inch of headspace.
- Raw Pack: Pack corn tightly into jars.
- Hot Pack: Ladle hot corn into jars.
Add Liquid: Cover the corn with boiling water, leaving 1 inch of headspace.
Remove Air Bubbles: Run a non-metallic utensil (e.g., a chopstick or plastic spatula) around the inside of the jar to release trapped air bubbles.
Wipe Jar Rims: Use a clean, damp cloth to wipe the rims of the jars.
Place Lids and Rings: Place lids on jars and screw on rings finger-tight.
Load Canner: Place jars in the pressure canner, ensuring they do not touch each other.
Add Water: Add the amount of water specified in your canner’s manual. Typically, this is about 3 quarts.
Vent Canner: Secure the canner lid and vent the canner by allowing steam to escape for 10 minutes.
Pressurize Canner: Close the vent (if applicable) and bring the canner to the correct pressure.
Process Jars: Process jars for the required time at the correct pressure. See table below for processing times.
Jar Size Raw Pack Time (minutes) Hot Pack Time (minutes) Pressure (Dial Gauge) Pressure (Weighted Gauge) Pint 55 55 11 lbs 10 lbs (at 0-1000 ft) / 15 lbs (above 1000 ft) Quart 85 85 11 lbs 10 lbs (at 0-1000 ft) / 15 lbs (above 1000 ft) Cool Canner: Once processing is complete, turn off the heat and allow the canner to cool naturally until the pressure returns to zero. Do NOT force cool the canner.
Remove Jars: Carefully remove the jars from the canner and place them on a towel-lined surface to cool.
Check Seals: After 12-24 hours, check the seals. Lids should be concave and not flex when pressed.
Store Jars: Remove rings and store jars in a cool, dark, dry place.
Common Mistakes and How to Avoid Them
- Insufficient Processing Time: This is the most dangerous mistake. Always follow recommended processing times precisely.
- Incorrect Pressure: Using the wrong pressure can lead to under-processing or jar breakage. Ensure your pressure gauge is accurate and adjust for altitude.
- Overfilling Jars: Leaving insufficient headspace can prevent proper sealing.
- Not Removing Air Bubbles: Trapped air can interfere with sealing and create an environment for bacterial growth.
- Using Damaged Jars or Lids: Inspect jars for cracks or chips and use only new, approved canning lids.
Troubleshooting: What to Do When Things Go Wrong
- Jar Didn’t Seal: If a jar doesn’t seal, you can reprocess it within 24 hours with a new lid. Alternatively, refrigerate the corn and use it within a few days.
- Liquid Loss During Processing: This is often due to improper venting or rapid cooling. Ensure proper venting and allow the canner to cool naturally. Minor liquid loss doesn’t necessarily mean the jar is not sealed.
- Discolored Corn: Discoloration can be caused by over-processing or using older corn. While discolored corn may not look appealing, it is safe to eat if properly processed and sealed.
Frequently Asked Questions (FAQs)
1. Can I Use My Grandma’s Canning Recipe?
It’s tempting to rely on family recipes, but many older canning recipes are outdated and unsafe. Always use tested recipes from reputable sources like the USDA Complete Guide to Home Canning or your local extension office.
2. What Type of Corn is Best for Canning?
Sweet corn varieties are best for canning. Choose fresh, mature ears that are plump and juicy. Avoid overripe corn, as it can become tough and starchy.
3. Can I Can Creamed Corn?
Canning creamed corn at home is not recommended due to the added thickness, which makes it difficult to ensure even heat penetration and can increase the risk of botulism.
4. How Long Does Canned Corn Last?
Properly canned corn can last for at least one year if stored in a cool, dark, and dry place. For best quality, use within two years.
5. How Do I Adjust Processing Time for High Altitude?
Altitude affects boiling point, which impacts processing times. Increase the pressure according to your altitude, as specified in the table above or your canner’s manual.
6. My Pressure Canner Doesn’t Have a Gauge. Can I Still Can Corn?
Yes, you can use a weighted-gauge pressure canner. Follow the manufacturer’s instructions for using a weighted-gauge canner. Refer to the table above for correct processing times for your altitude.
7. Can I Can Corn on the Cob?
Canning corn on the cob is generally not recommended due to the difficulty in achieving proper heat penetration. It’s safer and more efficient to cut the corn off the cob before canning.
8. What Should Canned Corn Look Like?
Canned corn should be brightly colored, clear, and free of any unusual odors or signs of spoilage. If the corn appears cloudy, discolored, or smells off, discard it immediately.
9. Do I Need to Add Salt or Sugar When Canning Corn?
Adding salt or sugar is optional and for flavor only; it does not affect the safety of the canning process. If desired, add ½ teaspoon of salt per pint jar or 1 teaspoon per quart jar.
10. Can I Reuse Canning Jars and Lids?
Canning jars can be reused indefinitely as long as they are free of cracks or chips. However, canning lids are single-use only and must be replaced with new lids for each canning session.
11. What Do I Do if I Suspect Botulism?
If you suspect botulism, do not taste or consume the food. Contact your local health department or poison control center immediately. Botulism is a serious medical emergency.
12. Can I Can Corn in a Water Bath Canner if I Add Vinegar to Increase Acidity?
No, adding vinegar will not make corn safe for water bath canning. The amount of vinegar required to lower the pH to a safe level would significantly alter the taste and texture of the corn. Only pressure canning can safely preserve corn.