The Difference Between Water Bath and Pressure Canning

There are two types of canning methods, water bath canning, and pressure canning. Both are safe food preservation methods but vary based on one very important factor: the pH of the food. Here you will learn the difference between the two methods and when to use one or the other. 

There’s nothing better than seeing a shelf lined with jars of food that you canned yourself! There is something so satisfying in the process of taking fresh vegetables, fruit, or animal products and preserving them for year-round enjoyment for your whole family. Many times people are reluctant to try home canning, but this is a process that has been used for many many years. It is safe and easy to do if you follow the right canning methods. Home food preservation does not need to be hard or complicated! All you need to know are proper techniques for food safety and the proper equipment and you can be canning your own food in no time!

Methods of canning

There are two different canning methods, water bath canning and pressure canning method. The method used is determined by the pH level of the food. High acid foods are canned with a water bath method, where low-acid foods need to be pressure canned. The acidity and method used are important to ensure that the food stays fresh in the canning jar and safe from pathogens such as botulism bacteria. The lower the pH level, the higher the acidity is. Water bath canning is safe with a pH of 4.6 or lower because the acid helps kill the pathogens. If the acidity is not high enough, you need to pressure can it to heat it to a safe temperature to kill off all pathogens and bacteria. 

Canning pots

The importance of safe canning techniques

The reason for canning is to preserve the food for long-term storage, kill off any bacteria or pathogens that can spoil the food, and ensure that it is safe to eat. The process of canning will kill harmful bacteria and pathogens such as Clostridium botulinum. The botulism spores are bacteria that cause harmful toxins. Water bath canning is good for foods that have a pH that is low enough to kill the pathogens, where pressure canning is needed to get the food to a high enough temperature to kill them. 

This is why it is so important to follow safe canning techniques. I am a “by the book” canner, which means I follow well-tested recipes that I know have the right acidy so I will can with ease and peace of mind! You need to ensure that you are canning something correctly based on the pH level because if you can incorrectly, you are increasing your risk for contamination and spoilage. You will know the canning method you need to use based on the pH, but don’t worry, by following trusted recipes there is no need to test the pH of canned goods. Trusted recipes come from places such as Ball Canning and the National Center for Home Preservation website. If you are making up your own recipes or following untested recipes, this can often lead to something that isn’t delicious– when people test for safety, they are also testing for quality and flavor. Don’t go through all the labor of canning to end up having a product no one wants to eat! 

Jars in a canner

Water bath canning

Foods that are high in acidity can be canned with a water bath canner because the high acidity will kill bacteria that can cause sickness or spoil the food inside. Foods that can be canned in a water bath include tomatoes, pickles, and fruits such as apples, sour cherries, peaches, and pears. You can also can things such as jam and sweet preserves. 

Canning rings on the bottom of a pot for water bath canning

To water bath can, you can use a canner, or a large pot that is big enough to easily fit all the jars and equipment. Any pot with a lid can work for a water bath canner, you can use a towel or canning rings at the bottom to keep the jars off the bottom of the pot. (See image) The pot or canner must be deep enough to have an inch of water above the jars inside, plus adequate room for the water to boil without splashing out. When water bath canning you will need to take care to sterilize the jars and equipment to ensure you do not contaminate the materials. The jars are filled and then added into the boiling water for a certain amount of time and the heat of the processing will seal the jars. Each recipe will tell you what the processing time is. 

If you are looking for a quicker method to water bath items, a steam canner is approved for water bath canning. Since the steam canner does not require the water to boil it can process much faster using steam. It also uses less water. 

Pressure canning

This method of canning requires some special equipment in order to heat the contents to a safe temperature to kill off germs or bacteria. This is the proper canning method for any food that has a higher pH of 4.6 or more and is the only safe method for foods with low acidity such as vegetables or meat. The canning process inside of the pressure canner can get the contents to a higher temperature than boiling water alone. The pressure canner closes the content inside and has a pressure gauge to tell you how many pounds of pressure you are creating inside. The pressure will vacuum seal the canning jars and kill any bad bacteria or germs. 

Jar of meat

The type of food that needs to be pressure canned includes low-acidic vegetables such as asparagus, carrots, and peas, and meats, seafood, and soups. 

It is important to note that a pressure canner is not the same thing as a pressure cooker! The main difference is the size of the cooker. It needs to be large enough to fit the jars properly. The USDA defines a pressure canner as one that can hold at least 4-quart mason jars. An instant pot also cannot serve as a pressure canner– and honestly, since the pressure cooker and instant pot only hold four jars, they are not an efficient method.

Borderline foods

Sometimes foods have an acid level that is borderline, so you will see a recipe call for something such as lemon juice to add enough acid to make it safe for water bath canning. Otherwise, it will need to be canned with a pressure canner. This is why you will sometimes see recipes with two different canning methods 

Jar of green beans

Canning books and resources

It is important to get your canning recipes from trusted resources! I have rounded up all of my favorite books that I use and trust in this blog post here. If you want to learn more about canning, you can enroll in “Yes, You Can!”, a canning course where I share how to create a stockpile of nourishing foods!

Downloadable resource

For a quick and easy resource, you can download the PDF below for a list of what types of foods that can be canned with the water bath method, or that need to be pressure canned. You can print it and keep in it with your canning supplies so it is in an easy to reach place! 

More canning resources

You can find more canning resources on the Pleasant Grove Homestead blog! 

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