Canning Articles

Cheat Sheet / Updated 03-09-2022

You can preserve food by water-bath canning, pressure canning, freezing, or dehydrating—all are time-honored and safe techniques. Canning and preserving are great ways to save foods at their peak freshness and flavor and to stock your pantry with nutritious and delicious fare. These checklists provide quick instructions for each food preservation method, information on how to adjust recipes for high-altitude processing, advice to ensure canning success, and details on must-have canning and preserving equipment.

Article / Updated 08-25-2021

You can preserve foods inexpensively by using canning, freezing, or drying techniques. Modern-day food preservation methods, such as water-bath canning, help you can and preserve with ease. After you understand the basic procedures for a food preservation method, you'll just need to concentrate on preparing your recipe. About canning food Canning is the process of applying heat to food that’s sealed in a jar in order to destroy any microorganisms that can cause food spoilage. Proper canning techniques stop this spoilage by heating the food for a specific period of time and killing these unwanted microorganisms. During the canning process, air is driven from the jar and a vacuum is formed as the jar cools and seals. Although you may hear of many canning methods, only two are approved by the United States Department of Agriculture (USDA). These are water-bath canning and pressure canning: Water-bath canning: This method, sometimes referred to as hot water canning, uses a large kettle of boiling water. Filled jars are submerged in the water and heated to an internal temperature of 212 degrees for a specific period of time. Use this method for processing high-acid foods, such as fruit, items made from fruit, pickles, pickled food, and tomatoes. Yum. Pressure canning: Pressure canning uses a large kettle that produces steam in a locked compartment. The filled jars in the kettle reach an internal temperature of 240 degrees Fahrenheit under a specific pressure (stated in pounds) that’s measured with a dial gauge or weighted gauge on the pressure-canner cover. Use a pressure canner for processing vegetables and other low-acid foods, such as meat, poultry, and fish. Don’t confuse a pressure canner with a pressure cooker, which is used to cook food quickly. A pressure cooker does not have adequate room for both the canning jars and the water needed to create the right amount of pressure to preserve foods. Older canning methods are unreliable and, for that reason, aren’t used or recommended today for home-canning. Occasionally, these methods are “revived” as being faster and easier than water-bath or pressure canning, but using other methods is like playing Russian roulette with your food safety. About freezing food Freezing foods is the art of preparing, packaging, and freezing foods at their peak of freshness. You can freeze most fresh vegetables and fruits, meats and fish, breads and cakes, and clear soups and casseroles. The keys to freezing food are to make sure it’s absolutely fresh, that you freeze it as quickly as possible, and that you keep it at a proper frozen temperature (0 degrees). Properly packaging food in freezer paper or freezer containers prevents any deterioration in its quality. Damage occurs when your food comes in contact with the dry air of a freezer. Although freezer-damaged food won’t hurt you, it does make the food taste bad. Here are three things to help you avoid freezer burn: Reduce exposure to air: Wrap food tightly. Avoid fluctuating temperatures: Keep the freezer closed as much as possible. Know what you want to remove before opening the door. Don’t overfill your freezer: An overly full freezer reduces air circulation and speeds freezer damage. About drying food Drying is the oldest method known for preserving food. When you dry food, you expose the food to a temperature that’s high enough to remove the moisture but low enough that it doesn’t cook. Good air circulation assists in evenly drying the food. An electric dehydrator is the best and most efficient unit for drying, or dehydrating, food. Today’s units include a thermostat and fan to help regulate temperatures much better. You can also dry food in your oven or by using the heat of the sun, but the process will take longer and produce inferior results to food dried in a dehydrator.

Article / Updated 03-26-2016

Like cooked food, canned food is subject to changes in appearance and nutritional content. Food is canned by heating what goes into the container and then sealing the container to keep out air and microbes. It is then reheated after the can/jar is sealed. Heating food often changes its color and texture. It also destroys some vitamin C. But canning effectively destroys a variety of pathogens, and it deactivates enzymes that might otherwise cause continued deterioration of the food. A modern variation on canning is the sealed plastic or aluminum bag known as the retort pouch. Food sealed in the pouch is heated but for a shorter period than that required for canning. As a result, the pouch method does a better job of preserving flavor, appearance, and heat-sensitive vitamin C. The sealed can or pouch also protects food from deterioration caused by light or air, so the seal must remain intact. When the seal is broken, air seeps into the can or pouch, spoiling the food. A more serious hazard associated with canned food is botulism, a potentially fatal form of food poisoning caused by the failure to heat the food to high-enough temperatures or for a long-enough time to kill all Clostridium botulinum (or C. botulinum) bacteria. Canning is based on temperatures and times necessary to destroy C. bot spores. C. botulinum is an anaerobic (an = without; aerobic = air) organism that thrives in the absence of oxygen, a condition nicely fulfilled by a sealed can. Botulinum spores not destroyed by high heat during the canning process may produce a toxin that can kill by paralyzing your heart muscles and the muscles that enable you to breathe. To avoid potentially hazardous canned food do not buy, store, or use any can that is Swollen, which indicates that bacteria are growing inside and producing gas. Damaged, rusted, or deeply dented along the seam, because a break in the can permits air to enter and may promote the growth of organisms (other than botulinum).

Article / Updated 03-26-2016

Water-bath canning, sometimes referred to as the boiling-water method of canning, is the simplest and easiest method for preserving high-acid food. Water-bath canning destroys any active bacteria and microorganisms in your food, making it safe for consumption at a later time. Prepare equipment and utensils. Examine the jars for nicks or chips, the screw bands for proper fit and corrosion, and the new lids for imperfections and scratches. Wash everything in warm, soapy water, rinsing the items well and removing any soap residue. Fill your canning kettle one-half to two-thirds full of water and begin heating the water. Heat extra water in a saucepan as a reserve. Submerge clean jars and lids in hot, not boiling, water. Use your canning kettle for the jars and saucepan for the lids. Transfer prepared food into the hot jars and release any air bubbles with a nonmetallic spatula. Add more prepared food or liquid to the jar after releasing the air bubbles to maintain the recommended headspace. Wipe the jar rims with a clean, damp cloth. You need the rims clean to properly place the lids. Place a hot lid onto each jar rim and hand-tighten the screw band. Make sure the sealant side is touching the jar rim. Suspend the jar rack on the inside edge of your canning kettle, place the filled jars in the jar rack, and lower the jar rack into the hot water. Make sure the jars are standing upright and not touching each other. If your jars aren’t covered by at least 1 inch of water, add boiling water from your reserve. Cover the kettle and heat the water to a boil, reducing the heat and maintaining a gentle boil. Start your processing time after the water boils. Maintain a boil for the entire processing period. At the end of the processing time, remove your jars from the kettle with a jar lifter and allow them to cool. Place them on a clean towel or paper towels. Completely cool the jars (12 to 24 hours). Test the seals on the cooled jars by pushing on the center of the lid. If the lid feels solid and doesn’t indent, you have a successful vacuum seal. Remove the screw bands from your sealed jars, then wash the sealed jars and the screw bands in hot, soapy water. This removes any residue from the jars and screw bands. Label your filled jars, including the date processed, and store them (without the screw bands) in a cool, dark, dry place.

Article / Updated 03-26-2016

Whether you can food yourself or buy it canned, canned food has the potential to spoil. To avoid making yourself sick with canned foods that have spoiled, watch out for these signs of a spoiled product: A bulging can or lid, or a broken seal A can or lid that shows signs of corrosion Food that has oozed or seeped under the jar’s lid Gassiness, indicated by tiny bubbles moving upward in the jar (or bubbles visible when you open the can) Food that looks mushy, moldy, or cloudy Food that gives off an unpleasant or disagreeable odor when you open the jar Spurting liquid from the can or jar when you open it Botulism poisoning can be fatal. Because botulism spores have no odor and can’t be seen, you can’t always tell which jars are tainted. If you suspect that a jar or can of food is spoiled, never, never, never taste it. Dispose of the food responsibly.

Article / Updated 03-26-2016

To can low-acid foods, you use a pressure canner. Pressure canning is the only safe way to can low-acid foods. Each step of the pressure-canning process is important to produce safe, home-canned foods: Assemble your equipment and utensils. Examine the jars for nicks or chips, screw bands for proper fit and corrosion, and new lids for imperfections and scratches. Wash them in warm, soapy water, rinsing well to remove any soap residue. Place clean jars and lids in a kettle of hot, not boiling, water. Never boil the lids because the sealant material may be damaged and won’t produce a safe vacuum seal. Fill your canner with 2 to 3 inches of water and heat the water. Refer to your owner’s manual for specific instructions. Fill the jars. You want the food snug, yet loose enough for liquid to circulate into the open spaces. Ladle boiling water into the jars, then release any air bubbles with a nonmetallic spatula. Leave the amount of headspace stated in your recipe. Wipe the jar rims with a clean, damp cloth. Place a lid on the jar (seal side down) and secure the lid in place with a screw band. Hand-tighten the band without overly tightening it. Place the jars on the rack in the bottom of the canner. Make sure you have the recommended amount of simmering water in the bottom of the canner. Lock the cover. Follow the instructions in the owner’s manual. Allow a steady stream of steam to escape from the pressure canner. Continue for 10 minutes or the time recommended in your manual. Close the vent, bringing the pressure to the amount specified in your recipe. Processing time starts when your canner reaches the required pressure. The pressure must remain constant for the entire processing time. After the processing time has passed, turn the heat off and allow the pressure to return to 0. Don’t disturb the canner while the pressure drops; jars that are upset may not seal properly. Approximately 15 minutes after the pressure returns to 0, remove the canner lid. Open the cover away from you to avoid the steam. After 10 minutes, remove the jars from the pressure canner with a jar lifter and completely cool the jars. Place them on a clean towel, away from drafts with 1 to 2 inches of space around the jars. Cooling the jars may take 12 to 24 hours. Test the seals on completely cooled jars by pushing on the center of the lid. If the lid feels solid and doesn’t indent, you’ve produced a successful seal. Remove the screw bands of the sealed jars and remove any residue by washing the filled jars in hot, soapy water. Make sure to thoroughly clean the lids and bands. Label your jars, including a date, and store the jars (without the screw bands) in a cool, dark, dry place.

Article / Updated 03-26-2016

Pickling preserves food in a brine solution. The perfect balance of salt, vinegar, water, and herbs and spices can safely preserve your pickled food. You can achieve this balance by precisely measuring your pickling ingredients: Salt: Used as a preservative. It adds flavor and crispness to your food, especially pickles. Use a pure, additive-free, granulated salt. Acceptable salts (shown in this figure) are pickling and canning salt (a fine-grained salt containing no additives), most kosher salt, and sea salt (produced from evaporated seawater). Salts not suitable for brining and pickling solutions are table salt and iodized salt, rock salt, and salt substitutes. Vinegar: A tart liquid that prevents the growth of bacteria. Always use a vinegar with an acidity level of 5 percent. The preferred vinegar for pickling is distilled white vinegar, which has a sharp, tart flavor. Use apple cider vinegar for a milder flavor. Water: Soft water is the best water for your brine solution. Distilled water, water with all minerals and other impurities removed, is also a good choice. If you use tap water, make sure it’s of drinking quality; if it doesn’t taste good to you, it won’t taste better in your food. Also, avoid using sparkling water. Herbs and spices: Use the exact amount of herbs or spices called for in your recipe.

Article / Updated 03-26-2016

Preventing food spoilage is the key to safe canning. Over the years, home canning has become safer and better. Scientists have standardized processing methods, and home canners know more about using these methods. When you follow up-to-date guidelines exactly, you don’t have to worry about the quality and safety of your home-canned foods. Here are some tips for handling, preparing, and processing your food: Wash and prepare your food well. This removes any dirt and bacteria. Always use the correct processing method for your food. Process all high-acid and pickled food in a water-bath canner. Process all low-acid food in a pressure canner. Process your filled jars for the correct amount of time. Also, if you’re using a pressure canner, process them at the correct pressure. Make altitude adjustments. If your elevation is higher than 1,000 feet above sea level, make the proper adjustments in processing time and pressure for your altitude. Depressurize the natural way. Allow your pressure canner to depressurize to 0 naturally. Let your jars cool. Allow your processed jars to cool undisturbed at room temperature.

Article / Updated 03-26-2016

Home cooks who live at high altitudes may be used to adjusting recipes; high-altitude adjustments apply to home canning, as well. Canning food safely requires your filled jars to be processed at a specified temperature or pressure level for a specified amount of time. If you live at altitudes higher than 1,000 or 2,000 feet above sea level, adjust your canning recipes for food safety. Water-bath canning: Generally, recipes are written for water bath canning at altitudes less than 1000 feet. If you live higher than 1,000 feet above sea level, follow these guidelines: For processing times of less than 20 minutes: Add 1 additional minute for each additional 1000 feet of altitude. For processing times of more than 20 minutes: Add 2 additional minutes for each 1000 feet of altitude. Pressure Canning: Pressure canning recipes are generally written for altitudes of less than 2000 feet. If you live higher than 2000 feet above sea level, make this adjustment: Increase pounds of pressure by 1/2 pound for each additional 1,000 feet.

Article / Updated 03-26-2016

Keep safety in mind whether you're water-bath canning or pressure canning. By canning foods safely, you can prevent kitchen accidents and food spoilage. Increase your chances for successful canning and maximum safety by following these guidelines: Used recipes made for modern-day canning (about 2000 or newer) and follow them exactly. Don’t increase or decrease your ingredients, processing time, or pressure level (for pressure canning). Don’t double recipes. If you want more than one recipe, prepare the recipe more than once. Use the proper ingredients: only unblemished and not overly ripe fruit or vegetables, and when a recipe calls for salt, use only canning or pickling salt. Use jars and two-piece lids approved for canning, and never reuse lids. Always label and date your finished product and use within one year of the date of processing. Periodically check your jars for any signs of spoilage and, if in doubt about the quality or safety of a preserved product, dispose of it without tasting.