What comes to your mind when you think of the preservation of food produce? Canning. Right? Canning is one of the most effective ways to preserve produce (especially seasonal ones) so they can be enjoyed all year round. The most common and healthy container for this kind of preservation is glass lidded jar of various sizes including 720ml, 500ml, and 250ml glass jars.
It is important to ensure that produce is properly canned to avoid contamination, spoilage and shortening of their shelf life. Hence, the a need to know and avoid some common mistakes easily made during canning. In this article, we will discuss 15 canning mistakes that could hamper your canning efforts.
Common Canning Mistakes Made When Using a Glass Lidded Jar
1. Not Sterilising Jars Properly
It is important to know that a thorough cleaning especially the sterilisation of your glass lidded jar is not an option if you want to avoid bacteria contaminating your food after canning. This is one of the first steps in canning. To sterilise your glass jars, place them in boiling water for up to 10 minutes then dry them on a clean rack.
2. Using Chipped or Cracked Jars
One of the unique advantages of glass preserving jars is their reusability. But it is necessary that before you reuse any jar, you inspect them to ensure they are not chipped or cracked. If a glass jar with a lid is compromised, it will not allow a proper sealing of the jar. This will allow air and contaminants into the canned food leading to spoilage and wastage.
3. Not Leaving Good Amount of Headspace
Headspace is important to prevent oxidation, allow expansion and ensure effective sealing. It is the space between the lid and the food in the jar. Regardless of the jar size, whether 720ml or 250ml glass jar, when too little headspace is left, the jar may break during the canning process. When it’s too much, excess air could be trapped in the jar, which can lead to improper sealing. Below are some recommendations when it comes to leaving headspaces in canning jars:
- For jam and jellies, leave about ¼ inch headspace
- For low-acid food, leave a 1-inch headspace.
- For fruits, tomatoes and pickles, leave ½ inch headspace.
4. Overfilling the Glass Jars
One of the effects of overfilling your glass jars is improper sealing. When you overfill the jars, you leave no headspace and just as discussed in the effect of leaving too little headspace above, the jar meat ends up breaking and spilling the food content leading to wastage. Simply avoid using small 250ml glass jars for food content of up to 260ml. Ensure you are certain of the quantity you are storing before shopping for glass containers for canning.
5. Underfilling Jars
It is important to have a good knowledge of the quantity of produce you will be canning to shop for the right sizes of jars. When jars are underfilled, it can lead to improper sealing which will eventually reduce the shelf life of the canned food. It is recommended to use sizes such as 250ml glass jars for relatively small quantities of food.
6. Not Removing Air Bubbles
Though this might look insignificant, it can alter the seal and lead to food spoilage. You must remove and use a non-metallic utensil or a plastic bubble remover to release air trapped in the food content before sealing the preserving jar.
7. Using the Wrong Canning Method
Understand that there are different canning techniques for different foods. To ensure you are using the right canning method for the kind of food you are processing do thorough research to avoid foodborne illness. Below are some recommendations:
- Use the water bath canning technique for high acidic food content like pickles, jam, and jellies.
- Consider the pressure canning technique for vegetables and meat, which are low-acid foods.
8. Not Adjusting for Altitude
It is important to know that altitude can affect canning processing time. If you live at a higher altitude, it will be good to learn about the recommended canning processing time at higher altitudes and adjust it because it is usually longer compared to the processing time at lower altitudes.
9. Reusing Some Lids
Just like not all jars can be reused, not all lids can be reused. Though reasoning lids may seem cost-effective, they can lead to wastage by affecting the seal and leading to the spoilage of your canned food. Plastic lids are highly not recommended for usage.
10. Not Wiping Jar Rims
After filling the lidded glass jar, you must clean the rim to remove food residue which could temper with the seal, aside from allowing the growth of mould.
11. Improper Storage of Lids
Lids, especially metallic and aluminium lids require a cool, dry place for proper storage. When they are not stored properly, they will easily rust or affect the seal.
12. Not Following Recipe Instructions
Trying new things is good. But when it comes to using an already existing recipe, it is recommended and beneficial to follow the existing instructions for such a recipe. This may include the processing time, canning technique, headspace, sealing method, etcetera.
13. Using Outdated Recipes
Before canning, ensure the recipe you are using is not outdated. Some recipes may become outdated if they pose health risks like foodborne diseases. Research and use recipes from recommended sources that reflect up-to-date food safety standards.
14. Not Processing for the Correct Time
The canning processing time is essential to create a vacuum seal and kill harmful bacteria hence the importance of following the right processing time for glass lidded jar. When you over-process, the quality of the food is tempered, while when you under-process, it can easily lead to food spoilage.
15. Cooling Jars Too Quickly
Cooling glass lidded jars quickly can be tempting but don’t be in a rush to do it because it can cause the glass jars to crack. Always allow the glass jars to cool gradually.