Fact Sheets And Publications
Fruits, acidified tomatoes, pickled products, and fruit spreads may be processed safely in a boiling-water bath.
Water bath canner - Water bath canners are available on the market, but any large metal container may be used. It should be deep enough to allow water to cover rack and jars, plus an additional 1 to 2 inches. A wire or wooden rack and a tight-fitting lid are necessary. A rack with dividers is helpful, because it keeps jars from touching each other and falling against the sides of the canner when processing.
- Check jars for cracks or chips. Regular and wide-mouth Mason-type, threaded jar are the best choice. For foods processed in a boiling-water bath canner, most pint and quart-size mayonnaise and salad dressing jars may be used with new two-piece canning lids; however, expect more jar breakage and seal failures than with standard canning jars. These jars are not made from as heavy a glass and have not undergone as high a heat-tempering process as canning jars. Do not use pickle, coffee, or baby food jars, or other one-stop commercial containers. The jar mouths may not be an appropriate size for sealing with canning lids.
- Secure a fresh supply of lids at the start of each season. Screw bands may be reused as long as they are in good condition.
General Recommendations for Packing Glass Jars
Raw pack - Pack raw fruit into jars. Cover with boiling hot syrup, juice, or water. It is necessary to leave headspace between the lid and the top of the food or liquid because of bubbling liquids and expansion of solids during processing. If too much product or liquid is added, contents may overflow during processing.
Hot pack - This method is preferred for fruit. Heat fruit in syrup, in water, or over steam. It also may be heated in juice extracted before packing. Fruit with a high juice content and tomatoes may be preheated without added liquid and then packed in the juice that cooks out.
Sweetened vs. unsweetened fruit - Additional sweetness is not essential to preserve fruit, but it helps canned fruit retain shape, color, and flavor. Sweetening may be in the form of sugar syrup, sugar, corn syrup, or mild-flavored honey. Brown sugar, molasses, or other strong-flavored sweeteners are not recommended. Their flavor will overpower the true fruit flavor.
Sugar Syrup - Combine sugar with water or juice extracted from some of the fruit. Use thin, medium, or heavy syrup, depending on the natural sweetness of the fruit and your own taste. Remember, however, heavier syrups supply many more calories.
Proportions for thin, medium, and heavy syrup
|Water or Juice||Type Syrup||Sugar (cups)||Yield (cups)|
|4 cups||Very light||1/2||4 1/2|
|4 cups||Light||1||4 3/4|
|4 cups||Medium||1 3/4||5|
|4 cups||Heavy||2 3/4||5 1/3|
|4 cups||Very Heavy||4||6|
If fruit juice is used as liquid, crush thoroughly ripe, sound, juicy fruit. Heat to simmering (185° to 210° Fahrenheit) over low heat. Strain through jelly bag or several layers of cheesecloth. Heat sugar and liquid together until sugar dissolves. Skim if necessary.
Sugar added directly to fruit - For juicy fruit to be "hot packed", add 1/2 cup sugar to each quart of raw prepared fruit. Heat to simmering (185° to 210° F) over low heat. Pack fruit in jars along with the juice that cooks out.
Other sweeteners - Light corn syrup or mild-flavored honey may be used to replace half the sugar called for in canning fruit.
Non-calorie or artificial sweeteners - Canning with artificial sweeteners is not advised. Saccharin loses some of its sweetening power when heated and may become bitter. When heated, aspartame is no longer sweet. Either of these may be added when the fruit is served.
Unsweetened fruit - Pack and can fruit in its own juice, in extracted juice, or in water. Process according to directions for sweetened fruit.
Processing by Boiling-Water Bath
General rules to follow:
1. Water in canner should be hot or boiling.
- Raw-packed fruits - water hot 140°F, not boiling.
- Hot packed fruits - water close to boiling; 180°F.
2. Place filled jars in canner. Jars should be on rack, not touching, so hot water circulates around them.
3. Jars should be covered by 1 to 2 inches of water. Have additional boiling water available in case it is needed to keep water level above jars. Water may have to be added during processing. Pour water between jars, not directly on them.
4. Cover canner with lid. When water comes to rolling boil, start to count processing time.
5. Boil gently and steadily for the time recommended for fruit being canned.
6. When processing time is up, remove jars from canner immediately, and place on towels or rack away from draft.
Test for Seal
Twelve to twenty-four hours after canning, check seal. Press metal lids at center. Lid should be slightly concave and not move when pressed in the center of the lid. Another way to test the jar seal is to tap the lid with the bottom of a teaspoon. If the jar is sealed correctly, it will make a ringing, high-pitched sound. If it makes a dull sound, the lid is not sealed or food is in contact with the underside of the lid. Do not be alarmed at popping sound as jars cool and some lids snap down. Screw bands may be removed from thoroughly cooled jars. Label jars with contents and date. Store in cool, dark, dry place.
Did You Know?
Canned fruit may float if packed too loosely in jars, if syrup is too heavy, or if some air remains in the tissues of fruit after heating and processing. To prevent this, use firm, ripe fruit and pack in light to medium syrup. Pack fruit closely in jar without crushing.
Fruit not covered by liquid may darken. This does not mean it is spoiled. Be sure fruit is covered by liquid and recommended headspace for fruit and liquid is used. Slip a slim rubber scraper between food and jar, tilting jar slightly to release trapped air bubbles. Always process for time recommended to destroy enzymes.
The pink, red, or blue color sometimes visible in canned apples, pears, and peaches may result from natural chemical changes that occur as these fruits are heated.
Check with your county Extension Family and Consumer Educator for more information on food preservation.
For canning of specific fruits, please see http://www.uga.edu/nchfp/.
Prepared by: Sue Snider, Ph.D.
Professor/Food Safety and Nutrition Specialist
UD Cooperative Extension
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