Food Preservation

Preserve It! Summer With Watermelon! 

by UCCE Master Food Preserver Laurie Lewis 

Nothing quenches thirst in the heat of the summer as a sweet watermelon can. Who else has childhood memories holding a generous slice in your hands, biting into the fruit as the juice ran down both arms?

Watermelon Rinds are Edible

July is National Watermelon Month. With over 400 miles of rich, loamy soil, California’s Central Valley is perfect for growing crops, making California one of the top producers of watermelon. Did you know this entire fruit is edible? Have you tried pickled watermelon rinds? National Center for Home Food Preservation has an excellent recipe to try: nchfp.uga.edu/how/pickle/fruit-pickles/watermelon-rind-pickles/

Not into pickled products or just don’t have the time? Make some fresh watermelon rind coleslaw: watermelon.org/recipes/watermelon-rind-coleslaw/

Watermelon Can Be Canned

How about saving some of that summer vibe in a pretty pink jelly for the long winter nights? Ball Complete Book of Home Preserving, 2024, has the following recipe just right for capturing that summer taste.

Zesty Watermelon Jelly Recipe

Makes about five 8-ounce jars

6 cups chopped watermelon, rind removed

½ cup (at least 5% acidic) vinegar—white balsamic, white wine, OR apple cider

4 Tbsp bottled lemon juice

5 cups granulated sugar

1 stem lemongrass, chopped

6 oz. liquid pectin

In a large stainless-steel saucepan, crush watermelon with a potato masher. Cover and heat gently over medium-low heat for five minutes. Remove from heat and crush thoroughly.

Transfer to a dampened jelly gab or a strainer lined with several layers of dampened cheesecloth set over a deep bowl. Let drip, undisturbed, for two hours. Measure two cups watermelon juice. If you do not have the required amount, crush more watermelon or add up to one-quarter cup unsweetened white grape juice.

Meanwhile, prepare boiling-water canner or atmospheric steam canner. Heat cleaned jars in canner until ready to use, do not boil (simmering water at 180 degrees F). Wash lids in warm soapy water and set aside with bands.

Transfer watermelon juice to a clean large, deep stainless-steel saucepan. Stir in vinegar, lemon juice, sugar, and lemongrass. Over high heat, stirring constantly, bring to a full rolling boil that cannot be stirred down. Stir in liquid pectin. Boil hard, stirring constantly, for one minute. Remove from heat and quickly skim off foam, if necessary.

Ladle hot jelly into a hot jar, leaving one-quarter-inch headspace. Adjust for headspace, if necessary. Clean jar rim. Center lid on jar. Screw band down until resistance is met, then increase to fingertip tight. Place jar in canner. Repeat until all jars are filled.

Water must cover jars by one inch in boiling water canner or come to the base of the rack in a steam canner. Adjust heat to medium-high, cover canner, and bring water to a rolling boil in a boiling-water canner or until there’s a steady stream of steam coming from the steam canner. Start timing and process half-pint jars: 10 minutes at 0 – 1,000 feet elevation, 15 minutes at 1,001 – 3,000 feet, 20 minutes 3,001 – 6,000 feet, 25 minutes 6,001 – 8,000 feet.

Turn off heat. For boiling water canner, remove lid and let jars stand five minutes. For atmospheric steam canner, let canner sit undisturbed for three to five minutes, then remove lid. Remove jars and cool on a toweled surface 12-24 hours. Check lids for seal (they should not flex when center is pressed). Label, date, and store in a cool dark place.

Enjoy your watermelon! 

The UC Master Food Preservers of El Dorado County are a great resource for answers to your food safety and preserving questions. Email us at edmfp@ucanr.edu. For more information about our program, events, and recipes, visit our website at ucanr.edu/sites/mfp_of_cs/. Find us on Facebook, too (UCCE Master Food Preservers of El Dorado County)!

This article first appeared in Village Life in June 2025. 

Preserve It!  Properly using canning jars helps ensure a safe outcome  

by UCCE Master Food Preserver of El Dorado County Laurie Lewis   

We are well into spring, heading toward summer. Seed catalogs were dog-eared months ago, seed packets are in a basket (or perhaps already opened and sown). There are high hopes of a great harvest this year, an abundance of fresh vegetables and fruit from the garden. Soon it will be canning season! Do you have enough canning jars and lids? Scouring the garage and estate sales for more? Let us help you with safe food preservation. Here are some myths and misconceptions about canning jars and lids.

Myth: Brand new canning jars fresh out of the box are sterile and don’t need to be washed. 

Truth: New jars are not sterile. 

Before use they should be checked for breakage or manufacturing defects and then washed. In fact, jars should always be checked and washed right before use (even if they were previously stored away clean).

Myth: Canning jars must always be sterilized before canning in them. 

Truth: Jars need to be sterilized only when the processing time is under 10 minutes.

Myth: The flat part of two-piece metal jar lid systems should be boiled before canning. 

Truth: The sealant used on most metal canning lids changed from rubber latex to plastisol decades ago, at which time the need to boil lids ceased. 

Boiling can damage the plastisol, resulting in seal failures. While it is safe to simmer lids (~180 degrees F) before use, it’s unnecessary and thus a waste of energy. All this said, do check the instructions from the manufacturer for your particular brand of lid for specific handling requirements.

Myth: Mayonnaise, sauce, and other similar commercial product glass jars can be reused for canning. 

Truth: These types of jars are not designed to be repurposed for home canning and are not recommended. 

They may not have the correct tempering to withstand high temperatures or long processing times, so jars may break. Some jar rim sizes vary slightly, leading to seal failures. Even those pasta sauce jars that say “Atlas” on them are not actually home canning jars, and the manufacturer specifically states on their website that they should not be used for home canning. The Hazel-Atlas Company made home canning jars long ago, but the company no longer exists. The “Atlas Mason” stamped on the sides of jars of sauce is just a marketing device. Just as with other commercial product jars, breakage and seal failures are a big risk if they are reused for canning. Because of the risk of breakage (and thus loss of food) and seal failures, reusing commercial product jars is not recommended. Should you decide to try it anyway, use them only for boiling water/steam canning. Do not use for pressure canning. Commercial product jars can be safely reused for storage of dry foods.

Good luck with your garden and have fun preserving those vegetables! 

The UC Master Food Preservers of El Dorado County are a great resource for answers to your food safety and preserving questions. Email us at edmfp@ucanr.edu. For more information about our program, events, and recipes, visit our website at link.ucanr.edu/mfp-cs. Find us on Facebook, too (UCCE Master Food Preservers of El Dorado County)!

Preserve It! Beware (and be aware) of vinegar with low acidity on store shelves  

by UCCE Master Food Preserver Laurie Lewis  

There’s a concern that, in the past few years, we have been seeing white vinegar with 4-percent acidity on store shelves. All our tested, safe recipes for home food preservation use 5-percent acidity vinegars. This one percent drop makes a big difference in preserving and pickling your foods safely. Vinegar below 5-percent is not adequate to control microbial growth in your home canning.

Here’s the problem: the U.S. Food and Drug Administration “only” requires vinegar to contain at least/at minimum 4-percent acetic acid (not 5-percent). There are some specialty vinegars which may range up to 8-percent, some quite expensive. Recipes generally are not written for these high percent vinegars (usually because of cost, color, cloudiness, or sharpness).

Safe, 5-percent vinegar is still for sale, but may be shelved next to vinegars that are not considered safe for canning and preserving. Read. The. Label.

Most likely the reason we are now seeing 4-percent vinegar is a cost factor with the manufacturers.
There is a vinegar called “Pickling Vinegar Base” that is only 2.5-percent acidity. The acidity is reduced by the addition of water. The color of the product and shape of the container looks just like regular 5-percent vinegar. It may also include salt as well as sugar. Do not use this for your home canning; it is for refrigerator pickles as the label says.

What if you find a vinegar with the percent acidity listed as “grains”? This refers to the measure of vinegar to water. The “grains” are divisible by 10 and are easy to match the percentage. 50-grain vinegar is the same as 5-percent vinegar. 40-grain vinegar is 4-percent, and so on.

What if you have used a vinegar with 4-percent acidity? It is recommended by the National Center for Home Food Preservation (NCHFP), if you have used vinegar with less than 5-percent acidity following a research-tested recipe:

1. If your canned food has been preserved for less than 24 hours using 4-percent vinegar, it is recommended to store the jars in the refrigerator to maintain the safety and quality of the product, as these foods are not considered safe to store at room temperature. These foods should be eaten within a month.
2. If your canned food has been preserved for more than 24 hours using 4-percent vinegar, it is recommended to discard the product. To ensure the safety of your home-canned products, do not use homemade vinegar or vinegar of unknown acidity in your home canning! The acidity of homemade vinegar is not consistent. Do not dilute the vinegar unless the recipe specifies.

Apple Cider Vinegar and Distilled White Vinegar are the two most common vinegars. They remain stable for up to two years. Store in a cool location, away from light. Discard after “best used by” date as recommended by manufacturer, or discard after one year for best quality. Specialty vinegars such as red or white wine vinegar, malt vinegar, balsamic, and flavored vinegars should only be used when a research-based recipe says to use one.

National Center for Home Food Preservation has some wonderful (free) pickling recipes for those last-of-the-growing-season vegetables and fruits you may still have in the garden or something you bought too much of at the grocery: nchfp.uga.edu/how/pickle. Now with your new knowledge of vinegars, perhaps you could try some of those recipes. Happy, safe home canning!

The UC Master Food Preservers of El Dorado County are a great resource for answers to your food safety and preserving questions. Leave a message at (530) 621-5506 or email us at edmfp@ucanr.edu. For more information about our program, events, and recipes, visit our website at ucanr.edu/sites/mfp_of_cs/. Find us on Facebook, too (UCCE Master Food Preservers of El Dorado County)!

Originally appeared on November 27, 2024 in the Mountain Democrat