This article will discuss how food pH is determined and how this is used to decide on an appropriate canning procedure. I will then give advice and guidelines on how to safely can and preserve each food group and explain why this is so important to the lifespan of the food and your health.
Here is a list of low-acid foods:
- Asian pears
- All vegetables
- All meat, including poultry and seafood
- Dairy products
Here is a list of high-acid foods:
- Salsa and sauces
A Quick Overview Of High and Low-Acid Foods
Below is a comprehensive list of high and low acid foods, along with a few examples of foods that are often considered to border the line between high and low acidity.
|High Acid Foods||Low Acid Foods||Foods with Variable pH|
|Most Fruits||Asian pears||Tomatoes|
|Jellies & Jams||Papayas||Dates|
|Salsa & Sauces||Vegetables|
|Sauerkraut||Meat, Poultry & Seafood|
|Yogurt||Soups & Stock|
Important Note: Foods with a variable pH should always be treated as low-acid foods for safety purposes.
You may be interested in this article I wrote: How to Choose the Best Fruit to Make Jam or Jelly.
How Is Food pH Determined?
The acidity of certain foods is determined by their pH value. In food canning terminology, 4.6 is considered the divide between low and high-acid foods, with anything lower than this considered to be highly acidic.
Food pH is determined by the concentration of hydrogen. Foods with a lower pH above 4.6 will naturally spur the growth of certain toxins and bacteria, so their canning procedures have to be done differently.
What Happens if Food Is Not Canned Properly?
If food is not canned properly according to its pH value, the bacteria naturally present in the food will inevitably multiply. The accumulation of bacteria may result in food poisoning, and the lifespan of the canned contents will be diminished.
The Type Of Bacteria That Multiplies in Improperly Canned Goods
The bacteria present in most foods is called Clostridium botulinum. These spores multiply rapidly in low temperatures and can cause a type of food poisoning called Botulism. If a canned low-pH food hasn’t gone through the correct canning process, these spores will quickly reproduce, destroying the integrity of the food and making it unsafe to consume.
What Are the Benefits of Canning?
Canning is an excellent way to preserve edible products for long periods of time. Home-canned goods can last up to 12 months if kept in the correct environment and save you precious preparation time in the future.
The benefits of canning include prolonged food storage and the use of recyclable metals. Canned goods can be kept in a cool, dry place for a long time and can give you more significant health benefits.
There are studies to suggest that some nutrients can be intensified after canning, and the concentration of specific vitamins and antioxidants (in tomatoes, for example) can be much higher after the canning process.
Additionally, although the process of canning can be time-consuming, doing it properly will preserve edible goods perfectly and save you time later on when preparing food.
What Are the Main Canning Procedures?
Maintaining correct canning procedures is essential to the overall quality of the food you wish to preserve. Improper canning can easily result in illness, so using a tried and tested procedure is important for a good outcome.
The main canning procedures use either a water bath or a pressure canner. The water bath method is used for products with a low pH level, which is highly acidic, and a pressure canner for products with a high pH level. It is essential to know the acidity of the product for successful canning.
The Water Bath Method: High Acid Foods
The foods that must be canned using the water bath method include all high-acid foods, such as most fruits, pickles, and yogurt. These require heating only to the boiling point of 100°C (212°F) since this is enough to destroy any bacteria that might be present.
This method requires the canner to place the prepared jars with their contents into a pot of boiling water, with the water sitting an inch or two (2.5 or 5 cm) above the lids. This method shouldn’t take more than 15 minutes, plus the time it takes to boil the water before the jars go in.
Once completed, it is advised to set the jars aside to cool down for a few hours to avoid injuries.
They can then be labeled and stored in a cool, dry place. The water bath method is sufficient to ensure that your preserves will keep for a long time without spoiling.
Related Article: How to Can Tomatoes Using the Water Bath Method | 10 Steps.
The Pressure Canner Method
The pressure canner method requires the use of a pressure regulator, which is necessary to ensure consistent pressure on your canned goods. The success of this method rests upon full internalized pressure for a prescribed number of minutes.
To use this method, the washed and filled jars are placed into a large pot with a lid.
The pressure regulator should be attached to the pot at all times. Pressure canning is a longer process than the water bath method and needs to be done correctly to ensure the goods are fully preserved.
What Type of Jars Are Best for Canning?
Whatever canning method you choose, using the appropriate jars is essential. If you use jars that cannot be made airtight or containers that are not resistant to heat, you will not be able to complete the canning process successfully.
The type of jar that is best for canning is a mason jar because it has a thick exterior, which makes them resistant to heat. They do not break or crack easily and can be quickly sealed to provide an airtight home for your canned goods.
Do You Have To Cook Food Before Canning?
You do not have to cook food before canning, but it is advisable unless you are pickling the food in the jar. Pickling is a form of preservation using vinegar or a salt solution. However, there should be no harm in canning raw foods as long as you’ve canned them correctly.
Additionally, the canning process semi-cooks your food, so if you don’t feel like cooking it first, it’ll be fine.
You can also can raw or cooked meats, depending on your preferences. You can complete a canning procedure with raw goods because the airtight container should protect them from the onset of bacterial growth.
Home Canning vs. Freezing and Drying
Home canning has numerous advantages over other types of long-term food preservation. It is cost-effective, and if completed correctly, it will preserve the shelf-life of your goods.
Below is a chart to give you a comparison between canning, freezing, and drying.
|Preservation Method||Cost||Shelf Life||Nutrient Retention||Ease of Method|
Low and high-acid foods need to be canned in specific ways to correctly preserve the products’ integrity, taste, and texture. Canning at home safely can be a bit laborious, especially if you are canning low-acid foods, but it’s worth the effort in terms of long-term preservation.
For more, don’t miss How to Make Jelly, Jam, and Preserves: A Complete Beginner’s Guide.
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