Home canning is an economical way to preserve your harvest for years to come. If you’re growing a home garden, or can go to local farmers/farmers’ markets and purchase in bulk, canning foods can save your half the cost of buying from the store. However, there are a number of concerns when it comes to home canning safety you need to know before you get started.
All vegetables begin losing some of their nutritional constituents the moment they are picked. The amounts of vitamins A and C, thiamin and riboflavin decrease within a matter of days. Even home canning will destroy some of the vegetable’s nutrition, however, if they are canned soon after harvesting, they can be more nutritious than the fresh crop at the local grocery store.
The primary concern with canning goods is creating an environment that prevents that growth of bacteria, yeasts and molds. Primarily, we’re concerned with Clostridium botulinum, or botulism, which is a deadly form of food poisoning.
To prevent the growth of bacteria, yeasts and molds, we:
Carefully wash fresh foods
Washing the food we’re canning can do a lot in the way of removing mold spores or bacteria that’s naturally occurring in the soil.
For some root vegetables, washing in hot water simply isn’t enough. Peeling them will remove the bacteria that washing couldn’t get to.
Hot packing is when we pack the canning jars with the fruits or vegetables we’re canning, and pour a hot liquid (usually water or vinegar) over the top before we process. This hot liquid will get into all of the nooks and crannies in the food and help kill even more bacteria.
Adding An Acid
For those low acid foods, the recipe often calls for adding an acid, such as lemon juice or vinegar, to help lower the pH and increase the acidity.
Using Jars and Lids in Good Condition
If you’re using the typical Ball canning jars and lids, visually inspect them for any defects and only use them once.
If you’re using reusable lids like these from Tattler, just make sure they are clean and warmed up before use.
Processing According to the Recipe
Depending on the food’s pH level, you may be required to boiling water can, or pressure can. Processing your canning jars according to it’s recipe will ensure you do it the correct way, for the correct amount of time.
Together, these practices help to remove oxygen, kill any unwanted bacteria, yeasts or molds, and create a high vacuum. A good vacuum will suck the canning jar lid inwards, creating a tight seal.
Botulism is a major concern with canning because, unlike some bacteria and molds, it thrives in low-acid foods with less than 2% oxygen. Botulism exists naturally in soil and water, and it present on most fresh food surfaces. However, they only multiple in the absence of oxygen, so it is harmless on fresh foods.
To prevent the growth of bacteria, molds, yeast, and especially Botulism, follow the instructions provided for each recipe carefully. Peeling, washing, and blanching can help reduce the amount of bacteria, etc. but sterilizing the jars properly, and processing the canned goods in the recommend way, for the recommend time, is the most important.
To make conversion easier, I’ve created two free printables that list processing times for Pints and Quarts for the most common home canned goods. Check out my post for your free downloads: Home Canning Time Guides.
The method and amount of time required for processing depends on the acidity in the food. Low-acid foods are not acidic enough on their own to prevent the growth of botulism or other bacterias.
Low-acid foods have a pH higher than 4.6. They include red meats, seafoods, poultry, milk and all fresh vegetables except for tomatoes. These foods must have acid added (lemon juice, citric acid or vinegar) to raise their acid levels or be processed at much higher temperatures (in a pressure canner).
High-acid foods have a pH of 4.6 or lower. These include fruit, pickles, sauerkraut, jams, jellies, marmalades and fruit butters.
This is where pressure canning come into play. A pressure canner uses pressure (measured in pounds per square inch – PSI) to reach temperatures higher than boiling water. These increased temperatures are what is needed to ensure the death of those pesky buggers.
Those who live in higher altitudes, namely above 1000 feet, know that water boils at a lower temperatures as altitude increases. I live pretty close to sea level, so I don’t have a lot of experience with canning in high altitude. Check out The Spruce‘s guide on how to adjust your canning recipes for your altitude.
Here’s a list of all of the recipes I’ve published that are suitable for canning: Recipes with Canning Instructions.
Now it’s your turn! Any canning safety tips you’ve heard over the years? Or canning fails? I just read that you don’t have to simmer Ball lids before use…not sure how I feel about that…
For a ton of FREE, vintage books on canning (including recipes that are over 100 years old!) check out Survivor Library.