Canning Basics

177578403Methods for canning foods at home have changed greatly since the procedure was first introduced almost two centuries ago. Since then, research has enabled home canners to simplify and safely preserve higher quality foods. Knowing why canning works and what causes food to spoil underscores the importance of following directions carefully.

How Canning Preserves Foods
Invisible microorganisms are all around us. Many are beneficial; others are harmful. All foods contain microorganisms, the major cause of food spoilage. Proper canning techniques stop this spoilage by using heat to destroy microorganisms. During the canning process, air is driven from the jar and a vacuum is formed as the jar cools and seals, preventing microorganisms from entering and recontaminating the food. It does not take long at 212 degrees Fahrenheit (F), the temperature at which water boils, to force air out, create a vacuum, and seal a jar. It does, however, take a specific amount of heat for a specific amount of time to kill certain bacteria. Although a jar is “sealed,” all bacteria are not necessarily killed. Adequate acid (as in pickled products and fruits) or sugar (as in jams and jellies) protects against the growth of some microorganisms. In low-acid foods, however, some microorganisms are not destroyed at 212 degrees F. Low-acid foods, therefore, must be heated to higher temperatures that can be reached only with a pressure canner. Low-acid foods, such as vegetables, meat, poultry, and fish, must be pressure canned at the recommended time and temperature to destroy Clostridium botulinum, the bacterium that causes botulism food poisoning. Canning low-acid foods in boiling water canners is absolutely unsafe

To read the full article on Canning Basics, including step by step instructions, click here.

Information compiled by Ruth Anne Foote, Extension Agent, Home Economics, Mercer County.
Updated by Marcia Jess, Extension Educator, Family and Consumer Sciences, Ottawa County.
Reviewed by Dan Remley, Extension Educator, Family and Consumer Sciences/Community Development, Butler County.

New to pickling? Do your homework

87633084Our garden is producing an overabundance of cucumbers this year. I thought I might try pickling some of them, but I’m not sure where to start. Any ideas?

First, if the cucumbers you’re growing aren’t a suitable variety for pickling, you might be disappointed in the results. Pickling cucumbers are usually smaller than cucumbers grown for slicing, and they tend to have thicker, bumpier skins. According to the cooking encyclopedia The Cook’s Thesaurus, the best varieties for pickling include gherkin, cornichon, Kirby and lemon cucumber.

But if you want to try, your first decision will be whether you want to make fermented pickles, which are pickled from lactic acid in a fermentation process over three to four weeks in a crock or other suitable container, or quick-process pickles, which are pickled from acetic acid from vinegar in a process that takes just a few days.

If you have a burpless variety growing in your garden, go for the quick process, because burpless varieties produce an enzyme at maturity that causes pickles to soften during fermentation. Always choose smaller cucumbers — they make crisper pickles.

You can find detailed guidance for pickling cucumbers (and other vegetables) in the U.S. Department of Agriculture’s Complete Guide to Home Canning, available online from the University of Georgia’s National Center for Home Food Preservation at In addition, Ohio State University Extension offers two fact sheets, “Making Fermented Dill Pickles” and “Quick Process Pickles,” at

Among the tips you’ll want to follow:

  • Pay strict attention to all guidelines, and process in a water bath canner according to recipe directions. Otherwise, your pickles may spoil or, worse, cause food poisoning.
  • Always trim about a quarter-inch from the blossom end of the cucumber to prevent pickles from softening.
  • Use only non-iodized salt made for pickling or canning. Regular table salt has anti-caking agents that can make the brine cloudy. Flake salt varies in density, so you can’t be certain you’re using the proper amount. If you want to make low-sodium pickles, use a tested recipe. Don’t try to make fermented pickles with less salt than in the recipe; the amount is necessary to inhibit the growth of undesirable bacteria.

Tips for the first-time home canner

166380548My mother-in-law gave me her pressure canner, and I’m hoping to do some canning for the first time this year. How should I prepare?

One of the best resources for beginner and experienced canners alike is the National Center for Home Food Preservation, hosted by the University of Georgia,

The site offers free access to many reliable sources of canning information, including the ability to download the U.S. Department of Agriculture’s Complete Guide to Home Canning. (Note: You can also purchase a spiral-bound printed version of the USDA guide for $18 from the Education Store of Purdue Extension,

Ohio State University Extension also offers food preservation information: go to, click on “Food,” and click on “Food Preservation” for a series of fact sheets. You’ll probably want to start with the four-page Canning Basics, which includes other recommended books for canning. Classes are also available; check out one near you:

As you gather materials and start doing some homework, there are a few other things you can do to make sure you’re all set when your garden bounty is ready for preserving:

  • Get the dial gauge on the pressure canner tested to make sure it’s giving an accurate reading. Check with your local Extension office for information about this service. If the gauge reads high or low by more than 2 pounds at 5, 10 or 15 pounds per square inch (psi), you’ll need to have it replaced.
  • It would be helpful to read the manual that came with the canner. If you don’t have it, you might be able to find it online, or you can try to contact the manufacturer for a copy.
  • Make sure you have all the equipment you’ll need for canning. You didn’t mention if you also received the accessories you may need, such as a jar lifter, a bubble freer or a funnel with an extra-wide mouth. You might also want to stock up now on jars and lids.
  • Find out what your altitude is. At more than 1,000 feet above sea level, water boils at a lower temperature, which means your canning process may not kill all bacteria if you don’t follow instructions for high-altitude canning. Some people are surprised that even Midwest states like Ohio have areas above 1,000 feet. There are plenty of smartphone apps that can tell you the altitude at your location, or you can inquire at your local Extension office or Soil Conservation Service. Or, go to the U.S. Geological Survey’s website at and click the menus for your state and county for a list of elevations at various locations in your area.