Canning 101

standard September 3, 2014 Leave a response

Pineapple. Tomatoes. Mushrooms. Tuna. Pinto beans. Cheeseburgers. What do these have in common, besides Stormy finding them delicious? They are all canned. Yes, even cheeseburgers. People give me strange looks when I tell them I make my own salsa, tomato sauce, etc., and can it at home. Old ladies can stuff, not 28-year-olds who still play in the rain.  Why do I can?

  • Love of Cooking: I love cooking, but I hate throwing away leftovers. Since it’s only the Boyfriend Unit and I, I don’t make large quantities of food because I don’t want it to go to waste. With canning, I stick it in a jar, boil it, then shove it in a closet until I want it!
  • Cost: It’s cheaper. This past weekend, I made 304 oz. of salsa for approximately $20. That’s 6¢/oz., compared to Newman’s Own Medium Salsa, at 21¢/oz.. Since the Boyfriend Unit can go through a pint a week, it really adds up!
  • Together Time: Instead of sitting on the couch watching Star Trek: The Next Generation, the Boyfriend Unit and I talk and joke around while peeling and coring tomatoes, chopping onions, squishing everything up with the immersion blender. We dance around each other, grabbing cutting boards, knives, gloves and more knives. We play “don’t let the dog eat that!” and “is it boiling yet?”
  • Quality Control: I like knowing what goes into my stomach. I’m not talking about preservatives, GMOs, etc., but the food itself. I can control the chunkiness of salsa, the ratio of tomatoes vs. onions, or the sweetness of apple butter.
  • Local Farmers: I try to shop at locally whenever I can (don’t get me started on Walmart). The money stays in the community, the environmental impact is less (since the food travels 20 miles to my tummy, instead of 1,200), less advertising, and I get to know who grows my food.
  • Satisfaction: I’ll admit, I like it when people tell me things like, “Your salsa is amazing!” or “No wonder Boyfriend Unit likes your cooking!” Gives me a warm fuzzy feeling inside.
  • Freshness: When I open that jar of salsa, I know it was canned at the peak of freshness, instead of ripening en route to the grocery store. This preserves the taste and nutrients of my food.

Before you begin canning, please read the USDA Complete Guide to Home Canning. It covers everything from canning types (in greater detail), approved recipes, tips and guidelines, and more. I still refer to it on a regular basis, and you should too.

A (Very) Brief History of Canning

In 1795, needing a way to transport food to his soldiers on the battlefield, Napoleon Bonaparte offered a reward to whoever could come up with a safe method of preserving food. After 15 years of research, in 1810, Nicolas Appert submitted his invention: sufficiently heating food then sealing it in an airtight container, and the 12,000 franc prize was his.

Canning continued to evolve, first by Peter Durand (using tin cans), then by Bryan Dorkin and John Hall (set up the first canning factory), John Mason (Mason jars), and so on. Due to exploding populations in the United States, Britain and Europe, demand for canning grew, processes were refined, and food safety improved (no more lead!).

Worldwide sales of canned goods estimated to reach $80 billion this year, and domestically, approximately 124 billion food, beverage and other metal cans each year. Home canning has seen a surge in popularity because of skyrocketing food prices, concerns over food safety, environmental concerns, and more.

How Home Canning Works

Food is ladled into glass jars, then covered with a metal lid and rim. The jars are placed in a canner filled with hot water, the food expands, and gases escape from the jars. Once the jars have been processed, the atmospheric pressure inside the jars is lower than the outside pressure, thus pulling the lid down and a vacuum seal is formed.

There are two basic types of home canning: water bath & pressure canning.

Water Bath Canning

High-acid foods, such as pickles, (most) salsas, tomatoes, apples, berries, etc., are the only foods you can safely process in a water bath canner, because high-acid foods prevent the growth of spores of the bacterium Clostridium botulinum. Once food is ladled into jars, the jars are sealed and fully submerged in boiling water. Once completed, the jars are removed and allowed to sit on a counter for 12-24 hours, fully covered.

Pressure Canning

Low-acid foods, such as meats, beans, corn, etc., must be processed at a higher temperature than boiling – usually 240 F. To get these higher temperatures, pressure canners trap steam and build up pressure inside the canner. This pushes air out of the jars and raises the temperature to 240 F, killing all harmful microorganisms. After processing and venting, the jars are removed from the pressure canner and allowed to rest on a countertop for 12-24 hours.


After canning is complete, the pressure inside the jars evens out and the jar is sealed. To see if a jar is sealed correctly, simply press the top of the jar. If the lid makes a popping noise, then the seal failed and the food must either be consumed immediately, frozen or discarded. If the lid won’t budge, then it’s good to eat!

Sources & Random Links

History of canning

Science behind canning

Other Links


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