There are two different kinds of canning. One is boiling water bath canning, which requires no special equipment beyond the canning jars and involves submerging the canning jars in a giant pot of boiling water. The other is pressure canning, which requires a very specialized piece of equipment called a pressure canner (no, that's not the same thing as a pressure cooker).
Depending on the acidity level of the food you are canning will determine which method is safe to use. If you use the correct canning method for the type of food you want to preserve, you will happily and safely preserve jars of delicious food for your pantry. However, if you mismatch the food and the canning method things could get scary (think botulism). Fortunately, it's really easy to get this right and dive into totally safe, worry-free canning.
A boiling water bath is simply a large pot (you can use a stockpot) with a rack on the bottom. Canning jars filled with food and with special canning lids secured are completely immersed in boiling water for an amount of time specified in the canning recipe. After processing, as the jars cool, a vacuum seal is formed. A boiling water bath can only heat the food to the temperature of boiling water.
High Acid Foods For Water Bath Canning
All acidic foods—fruits, pickled vegetables, sugar preserves, and tomatoes with a little added acidity (lemon juice, vinegar, or citric acid)—may be safely processed in a boiling water bath.
What Is Pressure Canning?
A pressure canner is a heavy-duty piece of equipment with a vent, a pressure gauge, and screw clamps. It is capable of heating the food in the jars to hotter than the temperature of boiling water.
The second thing to understand is which foods can be safely processed by which method. Here's the basic rule: all low acid a.k.a. alkaline foods must be processed in a pressure canner, not a boiling water bath. What does that mean? It means that any unpickled vegetable, including vegetable soup stocks and all animal products, cannot be safely processed in a boiling water bath. You need a pressure canner for them.
Low & No Acid Foods For Pressure Canning
Vegetables in plain or lightly salted water and animal products have a fairly neutral or slightly alkaline pH.
The reason for that is that although botulism bacteria are killed at the temperature of boiling water, botulismspores can survive that temperature. The spores can be eliminated by temperatures hotter than boiling water, which requires a pressure canner, or by creating an extreme pH (as is the case with vinegary pickled foods and sweet preserves).
Non-Acidic vs. Acidic Foods: Which Type Of Canning To Use
Vegetables in plain or lightly salted water and animal products have a fairly neutral or slightly alkaline pH. Because the pressure canner creates temperatures hotter than boiling water, it must be used to process these non-acidic foods.
All acidic foods—fruits, pickled vegetables, sugar preserves, and tomatoes with a little added acidity (lemon juice, vinegar, or citric acid)—may be safely processed in a boiling water bath. In boiling water bath canning, it is the acidity of the ingredients as much as the heat of the processing that safely preserves the food.
There is one other thing about canning that sometimes confuses people, and that is the word "canning" itself. For starters, we don't usually use cans, as in metal cans, for home food preservation anymore. We use glass jars, a fact that has led some enthusiasts to call the process "jarring." But jarring reminds me of something that is a harsh or abrupt jolt, so I'll keep using the word canning even though it isn't strictly accurate.
If you are canning a high acid food, you will use the water bath canning method.If you are canning a low acid food, you will use the pressure canning method. Acidity may be natural, as in most fruits, or added, as in pickled food. While low-acid canned foods contain too little acid to prevent the growth of C.
How Much Water Should I Add to my Pressure Canner? Unlike waterbath canning where you want your jars completely submerged by 1-2 inches of water, with a pressure canner you don't want the necks or lids of the jars covered. To start, just add two inches of water to your pressure canner.
Bring to a rolling boil, cover the canner and boil for 10 minutes if using 4-, 8- or 12-ounce jars or for 15 minutes if using 16-ounce jars. (Check individual preserve recipes for more specific processing times.) Let cool for 10 minutes before removing the jars from the pot.
Because of the acidity of high acid foods like jams, jellies, pickles, and fruit, the boiling water bath canning method is sufficient to block the growth of C.botulinum or destroy them more rapidly when heated. Foods with a pH below 4.6 are considered high acid and suitable for water bath processing.
Most fruit preserves and pickles are sufficiently high in acid to be canned via a method called water bath canning, where jars are submerged in boiling water for a prescribed amount of time.
It is perfectly fine to have your jars completely exposed to air when pressure canning. However, if you find you have too much water in the pressure canner and you see that the water is creeping up toward the neck of the jars, go ahead and remove some of that water before processing your jars.
Breakage can occur for several reasons: Using commercial food jars rather than jars manufactured for home canning Using jars that have hairline cracks Putting jars directly on bottom of canner instead of on a rack Putting hot foods in cold jars Putting jars of raw of unheated food directly into boiling water in the ...
Canning recipes will always call for a specific headspace to leave when you're filling jars. Headspace is the space from the top of the food in the jar to the top of the rim. An overfilled or underfilled jar may not seal correctly, which, as you now know, results in unsafe food. It's all about the seal.
Boiling removes the oxygen remaining in the jar, which helps to form a tight seal between the lid and the rim. The heat used for this method of canning is sufficient to kill vegetative bacterial cells found in the food. Only high-acid food with a pH of 4.6 or less can be processed using the boiling water bath method.
Use recommended processing methods and times. Wait 12 to 24 hours to test if jars are sealed. Reprocess jars that did not seal within 24 hours. Use new lids and reprocess for the original processing time.
All salsa with added bottled lemon juice tested well below a pH of 4.6 needed to prevent botulism. All varieties of salsa without added lemon juice tested above 4.6 and a risk for botulism. This research explains why an acid must be added to tomatoes when home canning them to lower the pH and prevent botulism.
If Clostridium botulinum bacteria survive and grow inside a sealed jar of food, they can produce a poisonous toxin. Even a taste of food containing this toxin can be fatal. Using boiling water bath canners when a pressure canner is intended will pose an increased real risk of botulism poisoning.
Rapid, forced cooling of a pressure canner can cause a rapid pressure and temperature change inside the canner, causing the liquid to "boil" out of the jars, leaving particles on the sealing rim and unsealing the jars.
Tomatoes and tomato products have traditionally been canned in a boiling water bath (212 °F). However, recent research shows that for some products, pressure canning will result in a high-quality and more nutritious product. Directions for canning a variety of tomato products are given below.
Cover the canner with a lid and cook over high heat until the water reaches a vigorous boil (212°F). Set timer for processing time called for in the recipe, adjusting for altitude if necessary. If the water stops boiling while processing, bring it back up to a full boil and restart the time.
Boiling water bath canning can be used to preserve high-acid foods such as fruits, pickles, relishes, acidified tomatoes, fruit jellies, jams, butters, marmalades, and preserves. Always check up-to-date canning information for correct processing times.
Introduction: My name is Lakeisha Bayer VM, I am a brainy, kind, enchanting, healthy, lovely, clean, witty person who loves writing and wants to share my knowledge and understanding with you.
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