Canning 101 – Pressure Canning

When preserving low-acid foods such as vegetables, meats and poultry, or mixtures of the same you will need to employ pressure canning methods to ensure proper food safety.

 

Clostridium botulinum can form spores that are very, very heat resistant. Even hours in the boiling water canner will not kill it. Left alive after canning, the germ will grow and produce a deadly toxin. – Foodsafety.gov
When you water bath can high acid foods, the temperature achieved is 212º F (100º C). This temperature is sufficient to kill all bacteria able to survive in the high acid foods. Since Clostridium botulinum cannot live in high acidity environments, water bath canning is effective against botulism poisoning for those foods.
HOWEVER, in low acid environments, Clostridium botulinum thrives, therefore we must bring the temperature above 212º F (100º C) in order to kill the spores and live bacteria.

 

Botulism is a rare, but serious illness caused by a germ called Clostridium botulinum. The germ is found in soil and can survive, grow, and produce toxin in a sealed jar of food. This toxin can affect your nerves, paralyze you, and even cause death. Even taking a small taste of food containing this toxin can be deadly. – CDC
The only way to get the heat above 212º F (100º C) is by applying pressure to the air, and trapping the steam from the water in a pressure canner. The pressure canner allows us to achieve temperatures of above 240º F and forces that heat into the foods inside the canning jars. It is important to know your local elevation as this also affects the pressure temperatures achieved by your pressure canner. This is essential for ALL low acid foods in order to assure all Clostridium botulinum bacteria are destroyed.

 

 Things you will need to pressure can:

  • Glass canning jars: These are what you are canning in. Despite the name canning you are actually using glass jars, not tin cans.:)
  • Lids and bands: Most new jars come with a lid and band already, but as you use up your canned food you will need new lids. The jars and bands are reusable countless of times provided they are free of chips or dents. Always start with new lids also called seals.
  • Funnel: A canning funnel or wide-mouthed funnel will save you much frustration trying to get your food into the jars. I would not can without one. I prefer the type with the measurements on the side, also saves headaches.:)
  • Jar Lifter: Another item you don’t want to do without… This gets the jars into and/or out of the hot water of the canner. They also help to move the jars around when filled with hot food. When you pull jars out the contents will still be boiling, so this is essential in my book.
  • Common kitchen utensils, such as wooden spoon, and ladle: Anything you will need to cook your recipe and get it in a jar.

Optional Items

  • Lid Lifter: Not so necessary any more. New theory on canning is that you do NOT need to pre-heat your lids/seals prior to canning. But if you prefer, you can use this to get the lids from the hot water bath.
  • Sure tight – Brand Tool: for tightening rings prior to canning, or removing bands once full seal is achieved. Also good for those with arthritis.

Pressure Canning Directions

(From Ball canning website with my notes)

READ through the instructions for your canner and the recipe you intend to use. Assemble all equipment and ingredients prior to beginning. Follow guidelines for recipe preparation, jar size, preserving method and processing time.

  • Note: I  end up with not enough jars when I make a recipe. If the recipe calls for 6 jars I will warm 8. Nothing is harmed and you aren’t left trying to figure out how to warm your jars while keeping your food warm and not scorched.

CHECK jars, lids and bands for proper functioning. Jars with nicks, cracks, even rims or sharp edges may prevent sealing or cause jar breakage. The underside of lids should not have scratches or uneven or incomplete sealing compound as this may prevent sealing. Bands should fit on jars. Wash canning jars, lids and bands in hot, soapy water. Rinse well. Dry bands.

  • Note: The new method is to not warm lids in simmering water. If this is what you are used to, go ahead, but it is considered no longer necessary.

HEAT jars in hot water, not boiling, until ready for use. Fill a large saucepan or stockpot half-way with water. Place jars in water (filling jars with water from the saucepan will prevent flotation). Bring to a simmer over medium heat. Keep jars hot until ready for use. You may also use a dishwasher to wash and heat jars. Keeping jars hot prevents them from breaking when hot food is added. Leave lids and bands at room temperature for easy handling.

  • Note: I have limited stove top space and I tend to can A LOT of food at once. My pressure canner takes up 2 of my 5 burners. Because of this, I put them in a 250° F oven for at least 20 minutes.

PREPARE for pressure canning. Fill the pressure canner with 2 to 3 inches of water. Place over medium-high heat. Bring to a simmer. Keep water at a simmer until jars are filled and placed in canner. Follow manufacturer’s instructions for usage instructions.

  • Note: I leave my rack at the bottom of the canner and use the jar lifter to maneuver jars into and out of the canner.

PREPARE tested preserving recipe using fresh vegetables, meat, poultry or seafood and other quality ingredients.

REMOVE hot jar from hot water, using a Jar Lifter, emptying water inside jar. Fill jar one at a time with prepared food using a Jar Funnel leaving headspace recommended in recipe. Remove air bubbles, if stated in recipe,by sliding the Bubble Remover & Headspace Tool or rubber spatula between the jar and food to release trapped air and ensure proper headspace during processing. Repeat around jar 2 to 3 times.

CLEAN rim and threads of the mason jar using a clean, damp cloth to remove any food residue. Center lid on jar allowing sealing compound to come in contact with the jar rim. Apply band and adjust until fit is fingertip tight. Place filled jars in canner until recipe is used or canner is full. Check that water level is about 2 to 3 inches high or that recommended in manufacturer’s manual.

  • Note: I like to spray my wet towel with vinegar to help clean the rims.

LOCK the pressure canner lid in place, leaving vent pipe open. Adjust heat to medium-high. Allow steam to escape through vent pipe. Once there is a steady stream of steam escaping, vent for 10 minutes to ensure there is no air (only steam) left in canner. Close vent using weight or method described for your canner. Gradually adjust heat to achieve and maintain recommended pounds of pressure.

PROCESS canning jars at the recommended pounds pressure for the processing time indicated in tested preserving recipe, adjusting for altitude (see altitude chart). Cool pressure canner by removing from heat. Do not remove the weighted gauge. Let canner stand undisturbed until pressure returns to zero naturally. Follow manufacturer’s instructions. Wait 10 minutes. Remove weight and unlock lid, tilting away from yourself. Wait 10 more minutes to allow jars to begin to cool.

  • Note: These steps are very important for both safety and to allow you jars to cool properly without bursting or losing a seal.

REMOVE jars from pressure canner and set upright on a towel to prevent jar breakage that can occur from temperature differences. Leave jars undisturbed for 12 to 24 hours. Bands should not be re-tightened as this may interfere with the sealing process.

  • Note: I usually  cover my jars with a towel as my home is drafty. I am not sure how the jars would react to a cold breeze. This may not be necessary. Just something I do.
  • Note: You should know your jars are sealing when you hear the lids make a “ping” sound. I always get a little excited when I hear that sound. Means I did something right. 🙂 This can happen quite quickly on some, but take longer for others. Be patient to let all jars have a chance to seal.
  • Note: Do NOT touch or push on the tops of the lids until you are sure they are all sealed. Pressure on the lid can cause a false “ping” and may not seal properly.

CHECK lids for seals. Lids should not flex up and down when center is pressed. Remove bands. Try to lift lids off with your fingertips. If the lid cannot be lifted off, the lid has a good seal. If a lid does not seal within 24 hours, the product can be immediately refrigerated. Clean canning jars and lids. Label and share then store in a cool, dry, dark place up to 1 year.

  • Note: Be sure to label with date and name of item. You will find that after you have done a lot of canning you will have similar items.  Tomatoes vs spaghetti sauce comes to mind.
  • Note: Follow proper can rotation techniques.
  • Note: I have also found that my canned food lasts longer than a year. Use your best judgement.

So there you have the basics, along with my thoughts on various steps. Let me know if you have any tips or tricks in the comments below, and feel free to link to any of your favorite recipes.

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7 thoughts on “Canning 101 – Pressure Canning

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