Guide E-319
Revised by Nancy C. Flores and Cindy Schlenker Davies
College of Agricultural, Consumer and Environmental Sciences, New Mexico State University

Authors: Respectively, Extension Food Technology Specialist, Department of Extension Family and Consumer Sciences; and County Program Director/Extension Home Economist, Bernalillo County Extension Office, New Mexico State University. (Print friendly PDF)

Selection and Care of Fruit

Select fresh, recently harvested, ripe but firm fruit that is free of blemishes, bruises, or diseases. Prepare only the amount of fruit that can be processed quickly. A canner load is a recommended amount to prepare and can at one time (Table 1). A load is usually 9 pints or 7 quarts.

Preserve Natural Color and Flavor

Preserve the fruit’s natural color and flavor by limiting exposure to air, packing hot into jars, observing the recommended headspace, processing quickly, and storing correctly.

To prevent discoloration of apples, apricots, nectarines, peaches, white cherries, and grapes that have been peeled, sliced, pitted, or stemmed, dip them in a solution of 3 grams of ascorbic acid (3,000 milligrams) to 1 gallon of cold water. One level teaspoon of the pure powdered form of ascorbic acid is 3 grams. Six 500-milligram tablets of vitamin C can also be used. One part lemon juice to four parts water can be used as a holding solution to prevent browning.

Both ascorbic acid and citric acid, available in several forms, are sold in supermarkets and drug stores. Ascorbic acid mixtures are more effective than citric acid mixtures. Follow manufacturer’s instructions when using the commercial mixtures.

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Sweeteners

Sugar and syrups help fruits retain flavor, color, and shape, but do not prevent spoilage. Sweetness is determined by the amount of sugar used: less sugar yields a lighter syrup with fewer calories. Sweeter syrups should be used with tart fruits. A 10% syrup is closest to the natural sugar content of fruit. See Table 2 for information on making sugar syrups.

Honey or light corn syrup can be substituted for up to half of the sugar in a syrup, if desired. Make enough syrup to fill the jars in one canner load.

Canning Without Sugar

Fruits can also be canned without sugar. Plain boiling water, unsweetened apple juice, pineapple juice, white grape juice, or a combination of these can be substituted for sugar syrups. For best results, it is recommended that sugar substitutes be used at serving time only, not in canning.

Hot Packing Fruits

Hot packing means heating food to the boiling point, simmering for 2–5 minutes, and filling hot jars loosely with hot food and liquid (juice, syrup, or water).

Hot packing removes air from fruit, shrinks it so that more fits in the jar, reduces fruit’s tendency to float in the canning liquid, and improves shelf life.

Canning Requirement List

• Cutting board

• Knife

• Peeler/corer

• Mixing spoons

• Tongs

• Measuring cup and spoon sets

• Canning jars

• Canning lids and screw bands

• Re-sealable plastic bags for leftovers

• Pot holders x 2

• Paper towels

• Cloth towels x 2

• Dish soap and scrubber

• Cooking pots in 1-quart and 5-quart sizes

• Large strainer

• Mixing bowl set in 2-, 3-, and 5-quart sizes

• Canning set

  - Jar lifter

  - Magnetized lid lifter

  - Funnel

  - Plastic spatula (to release air bubbles in jars)

• Pressure canner with rack for proper elevation OR

• Water bath canner with rack

General Canning Procedures

Use regular or wide-mouth Mason jars with self-sealing lids held in place by screw-on metal bands. The bands hold the lids in place during the processing and cooling periods, and can be removed and reused after cooling. Mason jars are made from tempered glass to resist high temperatures. Jars are available in 1/2 pint, pint, 1 1/2 pint, and quart sizes. Larger jars are not recommended for home canning. Do not reuse glass jars or bottles from commercially processed products such as mayonnaise because these jars will not withstand the water bath or pressure canner heating process.

Inspect jars carefully for cracks or chips and discard faulty ones. Wash jars in hot, soapy water and rinse thoroughly or clean using a dishwasher. To sterilize jars, keep jars hot in the dishwasher, a sink of hot water, or in a warm 180°F oven until they are filled. Check metal screw bands for signs of rust or dents. Discard corroded or dent- ed bands. Use only new lids and follow the manufacturer’s directions for preparing lids for canning. Do not use lids that are missing any gasket compound, dented, deformed, or older than five years from date of manufacture.

Fill hot jars with food, allowing headspace as directed in the recipe for each fruit. A wide-mouth food funnel keeps jars cleaner when filling. Remove air bubbles by carefully inserting a plastic or wooden spatula along the inside of the jar. Add food or liquid to achieve the recommended headspace. Wipe the top rim of the jar with a clean damp cloth or paper towel. Place lid on rim and tighten screw band comfortably tight. DO NOT touch screw band until jar has been processed and cooled. See Figure 1 illustrating these steps for jar filling.

The unfilled space between food or liquid in the jar and the lid is the headspace. This space allows for boiling and expansion of air in foods. The higher the temperature, the greater the expansion. The space also creates a vacuum as food cools. Headspace for home-canned fruit is generally 1/2 inch, but may vary. Recommended headspace for each fruit is located in the canning directions in Table 3.

Follow These Steps for Successful Boiling-Water Canning

1. Fill the canner halfway with water.

2. Preheat water to 140°F for raw-packed foods and to 180°F for hot-packed foods.

3. Load filled jars, fitted with lids, into the canner rack and use the handles to lower the rack into the water; or fill the canner, one jar at a time, with a jar lifter.

4. If necessary, add more boiling water so the water level is at least 1 inch above jar tops.

5. Turn heat to its highest position until water boils vigorously.

6. Set a timer for the minutes required for processing the food (Table 3).

7. Cover with the canner lid and lower the heat setting to maintain a gentle boil throughout the process schedule.

8. Add more boiling water, if needed, to keep the water level above the jars.

9. When jars have been boiled for the recommended time, turn off the heat and remove the canner lid.

10. Using a jar lifter, remove the jars and place them on a towel, leaving at least 1 inch between the jars during cooling.

Figure 1. Procedure for filling canning jars before processing (illustrations adapted from USDA, 2009, for New Mexico State University by Susan B. Portillo).

Test for Jar Seals

Remove screw bands when jars have cooled and test for vacuum seals by one of these methods:

• Press the lid center with your finger. If the lid springs up when released, it is not sealed.

• Tap the lid with a teaspoon. A sealed jar lid will make a ringing sound.

• Hold the jar at eye level and look across the lid. A sealed jar lid curves down slightly in the center.

Reprocessing Unsealed Jars

Remove lids from unsealed jars and discard. Check the sealing surface of jar for tiny nicks or cracks. If the jar has defects, discard it and replace it with another jar. If not, add a new lid and process for the same amount of time within 24 hours. Unsealed jars can be kept in the refrigerator if used within 3–4 days, or remove about an inch of the contents and freeze.

Storing Canned Food

Clean the outsides of sealed, cooled jars. Label with date and contents and store in a cool (50–70° F), dark, dry place away from sun, light, or dampness. Canned products are best if eaten within one year.

Accidental Freezing

Freezing may cause food in jars to spoil if the jars become unsealed. Freezing and thawing cause food to soften and lose eating quality. Protect jars from freezing by wrapping with layers of newspapers.

If Canned Food Spoils

Examine jars carefully before tasting fruit. Check lids for a vacuum seal. NEVER taste food from an unsealed jar.

Signs of food spoilage are streaks and dried food at the top of the jar, swollen lids, broken jar seals, rising air bubbles, and any unnatural color. Other indicators include bad or unnatural odor; spurting liquid; white, blue, green, or black mold; or foaming.

Dispose of any food you suspected of being spoiled. For safety, spoiled canned food and containers may need to be detoxified before disposal. Contact your county Extension office (https://aces.nmsu.edu/county/) for detoxification instructions.

Elevation Adjustments

All communities in New Mexico are above sea level, varying from 3,000 to 10,000 feet, with differences even within a county.

Use Table 4 to determine the elevation of your community and then select safe processing times for canning your fruit. The boiling temperature of liquids is lower at higher elevations (Table 5), and food must therefore be processed longer at high elevations.

References

https://nchfp.uga.edu/how/can2_fruit.html

https://nchfp.uga.edu/how/general/identify_handle_spoiled_canned_food.html

For more on this topic, see the following publications:

E-321: Freezing Fruit Basics
https://pubs.nmsu.edu/_e/E321/

E-326: Home Canned Sweet Spreads Made with Green Chile
https://pubs.nmsu.edu/_e/E326/

All Food and Nutrition Publications
https://pubs.nmsu.edu/_e/

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Nancy Flores is the Extension Food Technology Specialist in the Department of Extension Family and Consumer Sciences at NMSU. She earned her B.S. at NMSU, M.S. at the University of Missouri, and Ph.D. at Kansas State. Her Extension activities focus on food safety, food processing, and food technology.

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Cindy Schlenker Davies is the County Program Director and Extension Home Economist at NMSU’s Bernalillo County Extension Office. She earned her B.S. at Eastern New Mexico University and her M.A. at NMSU. Her Extension and public outreach work focuses on food processing and preservation and food safety.

To find more resources for your business, home, or family, visit the College of Agricultural, Consumer and Environmental Sciences on the World Wide Web at pubs.nmsu.edu

Contents of publications may be freely reproduced for educational purposes. All other rights reserved. For permission to use publications for other purposes, contact pubs@nmsu.edu or the authors listed on the publication.

New Mexico State University is an equal opportunity/affirmative action employer and educator. NMSU and the U.S. Department of Agriculture cooperating.

Revised November 2015