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How to safely preserve your summer tomatoes

Dehydrated tomatoes
Dehydrated tomatoes

Q. How can I safely preserve summer tomatoes?

A. 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 rest 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 percent 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 UCCE Master Food Preserver class this Saturday 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 a.m. to noon in the UCCE auditorium at 2156 Sierra Way, San Luis Obispo. There is a $5 fee. Register online at http://ucanr.edu/totallytomatoes

Are you interested in being a UCCE Master Gardener but need more information? Join us at the New Master Gardener Class informational meeting on Sept. 14 from 1-3 p.m. in the UCCE auditorium.

Rosemary Orr is a UCCE Master Gardener.

Got a gardening question?

In San Luis Obispo call 781-5939, Arroyo Grande, 473-7190 and Templeton, 434-4105. Visit us at http://ucanr.org/sites/mgslo/ or email us at anrmgslo@ucanr.edu. Follow us on Instagram at slo_mgs and like us on Facebook. Informative garden workshops are held the third Saturday of every month, 10 a.m. to noon at 2156 Sierra Way, San Luis Obispo. Garden docents are available after the workshop until 1 p.m. To request a tour of the garden, call 781-5939.