5 Tips for Canning Tomatoes

Don't give up on your tomato crop; can them and use them all year round. See pictures of heirloom tomatoes.

Growing tomatoes at home is easy for even novice gardeners. As long as you have a small area to set up shop (as small as an apartment stoop), you can grow these juicy and delicious vegetables. The only problem is, sometimes they yield a lot more than you expected and you end up with way more than you can eat. If after you've given away some tomatoes to friends and family you find that you still have some left over, there are options other than the compost pile. One of these is canning, which is a lot easier than it sounds. With just a little effort, you'll be able to enjoy those vine-ripe tomatoes year-round.


Pick the Best Tomatoes

Before the canning starts, you can help to ensure your success by picking out the right kind of tomatoes. You want to can at the peak of ripeness, so look for healthy, disease-free tomatoes. You'll also get a better result if your tomatoes are uniformly colored. Check out the skin to make sure it's tight and that there's no bruising. It's also important that the tomatoes you're using to can haven't been subject to frost while on the vine. This can knock the acidity down to unsafe levels for canning.


Use Stainless Steel

Glass jars are an acceptable alternative to stainless steel.

Fruits and vegetables are very affected by their environment, and tomatoes are no exception. Using anything other than stainless steel when canning can actually affect the taste of the end product. The acid in the tomato may react negatively to metals like aluminum and copper, and you could end up with some discoloration or bitter taste. Wooden spatulas should also be avoided because they can carry over flavors from other foods and affect the taste.


Add Acid

To make sure you end up with a safe product, it's important to get the acid right. Tomatoes used to have a higher acid count, but these days, experts say that newer varieties of tomatoes have a lower pH. In order to get the acid level to the desired point, add two tablespoons of bottled lemon juice for every quart of tomatoes you're canning. One-half of a teaspoon of citric acid will also do the trick. And don't worry about the taste because you can always add a little sugar to offset the lemon.


Get Creative

Pack your tomatoes full of flavor by adding other veggies.
Pack your tomatoes full of flavor by adding other veggies.

Canning a surplus of tomatoes doesn't mean you're stuck with a pantry full of plain old stewed tomatoes. There are a lot of creative things you can do with your tomatoes before you can them. Aside from whole stewed tomatoes, you can also dice them up for ease of use later on, or go ahead and make your pasta red sauce. You can even can prepare meat sauce, ketchup, tomato juice and homemade barbecue sauce. If you have some okra or zucchini in your garden, can them alongside your tomatoes to pack in some extra flavor, vitamins and minerals.


Know Your Altitude

A novice canner might underestimate the effect of altitude on the process, but it's not to be taken lightly if you want to do it right. Most of the canning techniques you'll find on the Internet assume that you'll be lower than 1,000 feet above sea level. If you happen to live in Denver, Colo., or any other city above 1,000 feet in altitude, you need to make an adjustment. A good rule of thumb is to add one minute of boiling time for each additional 1,000 feet above sea level.


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Related Articles


  • "A Primer on Canning Tomatoes." Seasonalchef.com, 2010. http://www.seasonalchef.com/preserves08.htm
  • "How Do I? ...Can Tomatoes" Uga.edu, 2010.http://www.uga.edu/nchfp/how/can3_tomato.html
  • "How to Can Fresh Tomatoes with a Water Bath Canner!" Pickyourown.org, 2010. http://www.pickyourown.org/canning_tomatoes.htm
  • "Selecting, Preparing and Canning Tomatoes." Uga.edu, 2010. http://www.uga.edu/nchfp/how/can_03/tomato_without_liquid.html