- Author: Rosemary Orr
- Editor: Noni Todd
By Rosemary Orr UCCE Master Food Preserver
How can I safely preserve summer tomatoes?
Welcome to August in San Luis Obispo County, well into the peak harvest time for locally grown tomatoes. In our garden, we have an abundance of tomatoes until October. They ripen so fast, I can hardly keep up. All summer long we make bruschetta, salsa, sauces, tomato sandwiches, tomato soup, tomato chutney… you get the picture. By the end of September, we are still going “totally tomatoes” in our garden and spend a weekend canning, freezing and dehydrating (drying) the remainder of our tomato crop. If you don't grow your own, farmers' markets or your grocery store will sell you cases of these beauties for you to preserve. One of my favorite cooking tomatoes is the Italian plum, also called Roma or paste tomatoes. Italian plum tomatoes have the fewest seeds, a firm texture, and make thick, rich tomato sauces. If you have beefsteak or heirloom, it's no problem. Different tomato varieties have different characteristics, so consider several types of tomatoes to add depth of flavor to your product. Fortunately, many canning recipes call for plain, ripe tomatoes; therefore, you can preserve your bounty of tomatoes, whichever varieties you may have available.
When processing in a boiling water canner or pressure canner, tomatoes must be acidified by adding bottled lemon juice, bottled lime juice, citric acid or commercial vinegar (with at least 5% acidity). The acidity in commercial products is standardized. However, in fresh lemons, limes or homemade vinegar, the acidity will vary and therefore is not reliable for use in home preserving. To safely preserve tomatoes using any method of preservation; canning, freezing or drying, always use a scientifically tested recipe from a reliable source.
At the U.C.C.E. Master Food Preserver class this Saturday, August 26, you can learn how to can whole tomatoes, salsa, and spicy tomato juice using a traditional boiling water canning method. In addition, Certified Master Food Preservers will discuss how to freeze and dry your own tomatoes. The workshop will be held from 10:00am until 12:00pm in the U.C.C.E. Auditorium located at 2156 Sierra Way, San Luis Obispo. There is a $5.00 fee. You can register online at
Are you interested in being a UCCE Master Gardener but need more information? Join us at the New Master Gardener Class Informational Meeting on Thursday, September 14th from 1-3 in the UCCE auditorium at 2156 Sierra Way, San Luis Obispo.