This information has been reviewed and adapted for use in South Carolina by P.H. Schmutz, HGIC Food Safety Specialist, and E.H. Hoyle, Extension Food Safety Specialist, Clemson University. (New 06/99. Revised 08/07.)
Tomatoes and tomato products have traditionally been canned in a boiling water bath (212 °F). However, recent research shows that for some products, pressure canning will result in a high-quality and more nutritious product.
Directions for canning a variety of tomato products are given below. Some recipes will give you the option of canning either in a pressure canner or in a boiling water bath. Some will give only boiling water bath times and others will give only pressure canning times. The recipes that specify only pressure canning have so many low-acid ingredients added to them that they are only safe when canned in a pressure canner at the specified pressure.
Whether you're canning tomato products in a boiling water bath or in a pressure canner, be sure you're canning them safely.
Because tomatoes have pH values that fall close to 4.6, you must take some precautions to can them safely. First, select only disease-free, preferably vine-ripened, firm fruit for canning. Do not can tomatoes from dead or frost-killed vines.
To ensure the safety of whole, crushed, juiced tomatoes and some tomato products, add acid, whether they will be processed in a boiling water bath or pressure canner. To acidify these tomatoes, add 1 tablespoon of bottled lemon juice or ¼ teaspoon citric acid per pint of tomatoes. For quarts, use 2 tablespoons of bottled lemon juice or ½ teaspoon citric acid.
The acid can be added directly to each jar before filling them with the product. If this makes the product taste too acidic, add a little sugar to offset the taste.
Note: Four tablespoons of vinegar per quart or 2 tablespoons per pint can be used instead of lemon juice or citric acid. However, the vinegar may cause undesirable flavor changes.
The processing time and pressures given for canning tomatoes and tomato products are for an altitude of 0 to 1000 feet. If you are canning at a higher altitude, make the following adjustments.
In a Boiling Water Bath: At altitudes of 1,001-3,000 feet, add 5 minutes to the processing time.
In a Dial-Gauge Pressure Canner: As the altitude increases, the processing time for each food stays the same, but the canner pressure must be increased as follows:
In a Weighted-Gauge Pressure Canner: At altitudes above 1000 feet, the processing time for each food stays the same, but the food must be processed at 15 pounds pressure.
Unless a tested recipe is used, all tomato-vegetable mixtures must be processed in a pressure canner, according to the directions for the vegetable in the mixture that has the longest processing time. Tomato-vegetable mixture recipes in this fact sheet may have shorter processing times because they have been tested for both pH and heat penetration. When the exact amounts specified in these recipes are used, these mixtures can be processed using the times given.
Quantity: An average of 23 pounds of tomatoes is needed for 7 quarts of tomato juice, or an average of 14 pounds of tomatoes for 9 pints of tomato juice. A bushel of tomatoes weighs 53 pounds and yields 15 to 18 quarts of juice, an average of 3¼ pounds of tomatoes per quart of juice.
Procedure: Wash, remove stems and trim off bruised or discolored portions. To prevent juice from separating, quickly cut about 1 pound of fruit into quarters and put directly into saucepan. Heat immediately to boiling while crushing. Continue to slowly add and crush freshly cut tomato quarters to the boiling mixture. Make sure the mixture boils constantly and vigorously while you add the remaining tomatoes. Simmer 5 minutes after you add all pieces. If you are not concerned about juice separation, simply slice or quarter tomatoes into a large saucepan. Crush, heat and simmer for 5 minutes before juicing.
Press both types of heated juice through a sieve or food mill to remove skins and seeds. Add bottled lemon juice or citric acid to jars according to directions above in "Acidifying Tomatoes and Tomato Products." Heat juice again to boiling. Add 1 teaspoon of salt per quart to the jars, if desired. Fill hot jars with hot tomato juice, leaving ½-inch headspace. Wipe jars rims. Adjust lids and process
To Process in a Boiling Water Bath:
To Process in a Pressure Canner:
Process pints or quarts for 15 minutes in a Dial-Gauge Pressure canner at 11 pounds pressure or in a Weighted-Gauge Pressure Canner at 10 pounds.
Procedure: Crush and simmer tomatoes as for making tomato juice. Add no more than 3 cups of any combination of finely chopped celery, onions, carrots and peppers for each 22 pounds of tomatoes. Simmer mixture 20 minutes. Press hot, cooked tomatoes and vegetables through a sieve or food mill to remove skins and seeds. Add bottled lemon juice or citric acid to jars. (See acidification directions in this fact sheet.) Add 1 teaspoon of salt per quart to the jars, if desired. Reheat tomato-vegetable juice blend to boiling and fill immediately into jars, leaving ½-inch headspace. Wipe jar rims. Adjust lids and process.
To Process in a Boiling Water Bath:
To Process in a Pressure Canner:
Process pints or quarts for 15 minutes in a Dial-Gauge Pressure Canner at 11 pounds pressure or in a Weighted-Gauge Pressure Canner at 10 pounds pressure.
Procedure: Wash tomatoes and okra or zucchini. Dip tomatoes in boiling water 30 to 60 seconds or until skins split. Then dip in cold water, slip off skins and remove cores and quarter. Trim stems from okra and slice into 1-inch pieces or leave whole. Slice or cube zucchini if used. You may also add four or five pearl onions or two ¼-inch thick onion slices to each jar.
Bring tomatoes to a boil and simmer 10 minutes. Add okra or zucchini and boil gently 5 minutes more. Add 1 teaspoon of salt for each quart to the jars, if desired. Fill hot jars with hot mixture, leaving 1-inch headspace. Remove air bubbles. Wipe jar rims. Adjust lids and process
Process: In a Dial-Gauge Pressure Canner at 11 pounds pressure or in a Weighted-Gauge Pressure Canner at 10 pounds pressure.
(about 3 pint jars)
2 quarts chopped tomatoes
¼ cup chopped green peppers
¼ cup chopped onions
2 teaspoons celery salt
2 teaspoons sugar
¼ teaspoon salt
Hot Pack: Combine all ingredients. Cover and cook 10 minutes, stirring occasionally to prevent sticking. Pour hot mixture into hot jars, leaving ½-inch headspace. Remove air bubbles. Wipe jar rims. Adjust lids and process.
Process: In a Dial-Gauge Pressure Canner at 11 pounds pressure or in a Weighted-Gauge Pressure Canner at 10 pounds pressure:
Pints ..................15 minutes
(about 6 to 8 pints)
5 pounds tomatoes
2 pounds chili peppers
1 pound onions
1 cup vinegar (5 percent acidity)
3 teaspoons salt
½ teaspoons pepper
Note: An equal amount of bottled lemon juice may be safely substituted for the vinegar, but do not use fresh squeezed lemon or lime juice because the acidity can vary and may not be safe enough. Sugar can be added to taste to overcome the tartness of the acid, if desired.Caution: Wear rubber gloves while handling chilies or wash hands thoroughly with soap and water before touching your face or eyes.
To Prepare Chili Peppers: Wash and dry chilies. Slit each pepper on its side to allow steam to escape. Peel peppers using one of the following methods: Oven or Broiler Method - Place chilies in oven (400 ° F) or broiler for 6 to 8 minutes until skins blister. Range-Top Method -Cover hot burner, either gas or electric, with heavy wire mesh. Place chilies on burner for several minutes until skins blister. Allow peppers to cool. Place in a pan and cover with a damp cloth. This will make peeling the peppers easier. Cool several minutes, then peel each pepper. Remove stem and seeds from peppers. Chop peppers.
Procedure: Wash tomatoes and dip in boiling water for 30 to 60 seconds or until skins split. Dip in cold water, slip off skins and remove cores. Coarsely chop tomatoes and combine with chopped peppers, onions and remaining ingredients in a large saucepan. Heat to boil and simmer 10 minutes. Fill hot salsa into hot jars, leaving ½-inch headspace. Remove air bubbles. Wipe jars. Adjust lids and process.
Process: In a boiling water bath for 15 minutes for pints.
IMPORTANT: Do Not Can Other Salsa Recipes unless they have been properly researched for safety. Other recipes may be frozen or stored in the refrigerator instead. For more salsa recipes that may be canned, contact your local Extension service or SC residents may contact the Home and Garden Information Center at 1-888-656-9988.
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This information is supplied with the understanding that no discrimination is intended and no endorsement by the Clemson University Cooperative Extension Service is implied. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed.