Fresh Preserving & Canning Questions

We want to make the creation process even easier for you. So we’ve compiled the questions asked most frequently by thousands of consumers regarding fresh preserving. Our answers draw on our years of experience in the canning industry and our compliance with current USDA guidelines. It’s our way of making sure your home preserved foods are the best they can be.

Are there special steps to follow when preparing home canning jars and lids for processing?

Yes, there are specific instructions for selecting, cleaning, and preheating jars, lids and bands prior to use. Always refer to the manufacturer’s instructions. If they are not available, this general information will help. Select home canning jars that have no visible scratches, nicks, chips, or uneven rims. Examine lids to ensure they are not scratched, have even and complete compound, and have not been used previously for canning. Bands should be easy to adjust on the jar, without any signs of warping or corrosion.

Wash jars, lids and bands in hot soapy water. Rinse well. Dry lids and bands; set aside. Jars must be preheated and kept hot until they are used. To preheat jars, completely submerge them in water that has been brought to a simmer (about 180°F). They should remain at this temperature until they are used, removing one at a time as needed. If jars are used for any recipe that is processed less than 10 minutes, the jar must be sterilized. To sterilize jars, submerge jars in water and boil 10 minutes. (For altitudes higher than 1,000 feet above seal level, refer to Canning Basics.) Allow sterilized jars to remain at a simmering temperature until they are used.

For additional information, see Canning Basics and Step-by-Step.

Can fruit be safely canned without the addition of sugar?

Yes, fruit may be canned without sugar. Whether you have a dietary requirement, or a desire to make healthy eating choices, home canning is a simple way to reduce the amount of sugar in your diet.

To can fruit without sugar, select fully-ripe, firm fruit at its peak flavor. Water or unsweetened fruit juice may be used in place of a sugar syrup. Prepare and process fruit as directed in recipe. Use only the Hot Pack method when canning fruit without sugar. For more detailed information see Canning Basics and Step-by-Step.

Non-sugar sweeteners may be used as a replacement for sugar. For best results, add non-sugar sweetener just before serving canned fruit. Spices, herbs and flavoring extracts can also be used to enhance the flavor of fruits being canned without sugar.

For flavorful low-sugar recipes, see Recipes.

Can vegetables be safely canned without salt?

Yes, vegetables may be canned without salt. The measure of salt called for in most vegetable recipes is too small to help prevent spoilage; it is there only for seasoning. To prepare vegetables with less or no salt, simply omit salt or reduce the amount of salt to taste. Do not omit or reduce salt from pickled foods or seafoods. Adding your favorite herbs or spices can easily enhance the flavor of vegetables. For savory reduced salt vegetables, see Recipes.

Sometimes when canning beets the color changes from red to pink or even white. How do I prevent color loss?

Leave 1 to 2 inches of the taproots and stems on the beets. Boil beets until the skins easily slip off. Drain beets. Remove skins and trim away the taproots and stems. Now, the beets should retain their distinctive red color when canned. They may be canned whole, sliced or diced.

How can I determine if the home canning recipes received from friends and family are safe to use?

While you may have home canning books or recipes considered to be family heirlooms or treasures, they may not always be safe to use. In 1989, the USDA updated their home canning guidelines based on safety and quality. Therefore, a home canning book or recipe that was published before 1989 may be outdated and could affect the safety and quality of your home canned foods. Be sure the canning book or recipe you use complies with up-to-date guidelines.

The Ball Blue Book® of Preserving and the USDA’s Complete Guide to Home Canning offer up-to-date information and recipes.

How do I determine what method to use?

To determine which method is appropriate for the food types you are canning, refer to Canning Basics. For up-to-date recipes indicating the correct processing time, see Recipes.

How do I know if a jar of home canned food is spoiled?

When up-to-date guidelines, such as those outlined on this site, are followed exactly, there should be little concern about the quality and safety of your home canned foods. As with commercial packaged foods, it is always wise to examine any food before using it. When you take it from the shelf, check each jar to see that it has retained a vacuum seal and that no visible changes have taken place during storage.

Unsealed jars indicate the possibility of spoilage. Spoilage produces gases that can break seals and/or cause the lids to swell. If a lid can be removed without the use of pressure to release a vacuum, do not use the food. Other signs of spoilage include mold, bubbling gases, cloudiness, spurting liquid upon opening, seepage, yeast growth, fermentation, sliminess or disagreeable odors. If you know that low-acids foods were improperly processed (i.e., in a boiling-water canner as opposed to a steam-pressure canner) do not use them under any conditions. If you suspect spoilage, dispose of the food without tasting it. Dispose of all spoiled foods in a manner that will prevent consumption by humans or animals.

When cooked jams or jellies prepared with liquid fruit pectin do not set, how can they be fixed?

Before attempting to remake a jam, jelly or other fruit spread made with liquid fruit pectin, wait two weeks to determine if the product will gel. Not all recipes set within 24 hours. If after two weeks the product does not have a good set, it can be re-cooked in order to achieve a firmer texture.

Measure the unset product to be re-cooked. Prepare only a single batch at one time. For each quart of unset product, measure 3⁄4 cup sugar, 2 tablespoons lemon juice and 2 tablespoons liquid pectin, set aside. Place one quart of unset product into a medium saucepan and bring to boiling over medium-high heat. Quickly add the sugar, lemon juice and liquid pectin; bring to a rolling boil, stir constantly. Boil mixture hard for 1 minute. Remove from heat, skim foam if necessary. Carefully ladle hot mixture into hot jar, leaving 1⁄4-inch headspace. Adjust new lid and band on jar. Repeat until all jars are filled. Process in a boiling-water canner for the full length of time indicated in the original recipe.

Can I use the jars in the oven for baking?

We do not recommend baking in any size or shape of Ball or Kerr canning jars. The glass used for Ball and Kerr canning jars is not tempered for oven use and is not meant to be used as bakeware. The jars are safe to use for home canning recipes, cold or room temperature food storage, cold beverages, and crafting.

How long does home canned food last?

Foods canned following a tested recipe, correct processing method and processing time can be safely stored for one year. After one year, natural chemical changes may occur within canned foods that could lessen the quality. These changes may affect the flavor, color, texture or nutritional value. For this reason, canned foods stored the longest period of time should be used first. Labeling each jar with the date the product was canned as well as the type of the product will help you easily identify inventory that needs to be rotated.

Before storing sealed jars, remove the bands. Wash bands, lids and entire surface of the jars to remove any food residue. Rinse and dry. Bands need not be replaced. However, if you choose to store jars with the bands on, be sure the bands are completely dry.

Even foods that are properly processed and canned will lose some of their nourishing qualities over an extended time. This loss may be accelerated if the food is stored at temperatures above 70°F. On the other hand, the food should not be stored where it might be subject to freezing since the food can expand and break the seal. Storing home canned foods between 50°F and 70°F is ideal and may help preserve the food for a longer period of time.

Light hastens oxidation and destroys certain vitamins. Light will also cause certain foods to fade in color. To protect home canned foods from the deteriorating effects of light, store jars in a place that does not receive direct sunlight. It is best to keep home canned foods in a cool, dry, dark place.

How tightly should the bands be applied?

Using just your fingers, screw bands down evenly and firmly just until a point of resistance is met – fingertip tight. Do not over tighten bands by using the full strength of your hand. Over tightening bands can prevent air from venting out of the jars, resulting in buckled lids or seal failure.

After processing, bands may appear to have loosened. This is normal. Do not retighten bands immediately after processing since this may break the seal that is forming.

If home canned foods have frozen during storage, are they safe to eat?

If the food was processed according to current home canning recommendations (see Canning Basics), and the jars are still vacuum sealed, the food should be safe to eat. Examine jars closely – sometimes freezing can cause damage to the vacuum seal, or jar breakage. Home canned food that has been frozen during storage may be less desirable due to changes in texture, flavor, nutritional value and color.

Is it safe to pack fully cooked food into jars, adjust the caps and store it without additional heat processing?

The method of canning you described is referred to as the open kettle method. Open kettle canning is not a safe method to use. This method results in a high rate of food spoilage. Although the food is hot and may be fully cooked, it may not reach and maintain the temperature necessary to destroy spoilage microorganisms. If spoilage microorganisms are not destroyed, the food can spoil even though the cap is tightly closed.

For the proper processing procedures and methods, refer to Canning Basics, Step-by-Step. For recipes with correct processing methods and times, see Recipes.

Is there a conversion for using the boiling-water canner instead of a steam- pressure canner when home canning vegetables?

No, there is not a safe way to convert processing vegetables, meats, seafood and combination recipes from steam-pressure canning to boiling-water canning. Recipes in these categories are low-acid foods. The steam-pressure canner is required to achieve the high temperature necessary to destroy microorganisms that can cause spoilage and illness.

I am following a low sodium diet. May I safely can my pickle recipes with less salt?

Only fresh pack (or quick) pickle recipes may be safely adjusted to reduce salt. Reducing the amount of salt or omitting the salt from fresh pack pickle recipes will change the flavor and texture of the finished pickled product.

Salt is an important ingredient in fermented and brined pickle recipes. It should not be reduced or omitted when preparing this type of recipe.

What causes a lid to become corroded or rusted while it is on a jar of home canned food?

Following the manufacturer’s instructions for preparing and using lids will reduce the possibility of corrosion. It is also important to use home canning lids that have been stored in a cool, dry, dark place.

If corrosion does occur, one of the following factors may have been the cause:

  • Not preparing lids for use according to manufacturer’s instructions;
  • Scratch in the coating applied on the lid;
  • Incorrect headspace;
  • Strong concentration of salt or acid;
  • Improper storage of lids prior to canning;
  • Not cleaning bands before storing sealed jars;
  • Not cleaning lid and jar surfaces with a damp cloth to remove food particles and residue;
  • Improper storage of home canned food.

A jar of home canned food with a lid that becomes spotted with rust may be used as long as it was properly processed using up-to-date guidelines (see Canning Basics), and there is a vacuum seal on the jar. Please note this applies to surface spots only.

What causes buckled lids?

Buckled lids appear to warp, bulge, or crease upward near the outer edge. Ball brand and Kerr brand two-piece vacuum lids are made to release pressure by venting air from the jar during processing and cooling. When the lid does not vent, pressure build-up warps the lids and may prevent a good seal.

There are several potential reasons for this to occur:

  • Applying the bands too tightly causes buckling that is usually apparent immediately after processing.
  • Boiling the lids before use softens the sealing compound too much which may prevent venting and result in a buckle or no seal.
  • Food spoilage due to incorrect processing produces gases inside the jar that force the lid to buckle or unseal.

Preventing buckled lids is simple. Always process foods using up-to-date guidelines, prepare lids according to manufacturer’s instructions, and apply bands just until a point of resistance is met – fingertip tight.

What causes color changes in home canned foods?

Color changes typically result from the following:

  • How the produce is handled between harvesting and canning;
  • Growing conditions for a particular season;
  • Overcooking or heating at too high a temperature;
  • Improper storage conditions;
  • Low sugar content in a recipe;
  • Quality of water used in recipe preparation, or
  • A reaction with the type of utensil used for cooking.

Following a reliable canning guide such as the Ball Blue Book® of Preserving will give detailed information on how to avoid color changes in home canned foods.

What causes jars to break during processing?

Home canning jars are glass containers and therefore should be handled carefully. It is important to always follow the manufacturer’s instructions when preparing and using home canning jars. It is also important to visually examine jars before use.

If jar breakage does occur, check the following points to determine if one of them is the cause:

  • Using commercial or old-style home canning jars;
  • Using a metal utensil to remove air bubbles;
  • Using steel wool or a brush with a wire stem to clean jars;
  • Using a metal utensil to remove food for serving;
  • Handling and storing jars in such a way to cause scratching on the outside of the jar;
  • Placing hot food into a room temperature jar;
  • Placing a room temperature jar into boiling water;
  • Lifting a jar out of the canner and placing it directly on a cool counter or a wet surface;
  • Using a processing method that is not approved for home canning;
  • Abusive handling of a glass container.

For detailed information about the proper use of home canning jars, see Canning Basics and Step-by-Step.

What causes lids to come unsealed or not seal at all?

Always use current home canning jars, lids, bands, processing methods and processing times to ensure there is no seal failure or that unsealing does not occur. It is important to follow the manufacturer’s instructions when preparing jars, lids and bands for use. It is also important to examine the canner to be certain it is in good working condition. When home canning, always use an up-to-date, tested recipe from a reliable source.

If seal failure or unsealing does happen, check the following points to determine if one of them is the cause:

  • Insufficient or incorrect processing;
  • Over-tightening the band before processing or re-adjustment of the band after processing;
  • Incorrect headspace;
  • Reusing lids;
  • Using commercial jars;
  • Not preparing lids for use according to manufacturer’s instructions;
  • Not removing air bubbles from the jar or cleaning the rim of the jar before applying the lid.

For more detailed information about the proper use of home canning jars, lids, bands and canners, see Step-by-Step.

If a lid does not seal within 24 hours after processing, the product must be

1. Reprocessed immediately, 2. Stored in the refrigerator and used within a few days, or 3. Placed in a proper freezer container and frozen.

To safely reprocess a product, remove the food from the jar. If it was hot-packed, reheat the food. Pack it into a clean, hot jar. Allow the correct headspace for the type of food being canned. Place a new lid on the jar. Reprocess the product using the correct processing method and follow the entire processing time as recommended by an up-to-date recipe from a reliable source.

What causes loss of liquid from jars during processing?

Loss of liquid from jars during processing typically result from the following:

  • Food not heated before packing into jars;
  • Food packed too tightly;
  • Incorrect headspace;
  • Air bubbles not removed before capping jars;
  • Steam-pressure canner temperature allowed to fluctuate during processing;
  • Jars not covered with water in boiling-water canner;
  • Jars removed from canner too quickly after processing is complete;
  • Food absorbed liquid.

The food in the jar that is not covered by liquid may darken, but should not spoil as long as it was processed according to up-to-date guidelines (see Canning Basics) and there is a vacuum seal on the jar. Do not open jar to replace liquid.

For detailed information on proper processing procedures that will help avoid loss of liquid from jars, see Step-by-Step.

What is headspace? Why is it important?

The space in the jar between the top surface of the food or its liquid and the inside of the lid is called headspace. Leaving the correct depth of headspace is essential to achieve a vacuum seal.

If jars are overfilled, the contents may siphon or boil out during processing. Any food residue remaining on the jar rim, such as grease, juice, seeds or pulp can prevent the formation of an airtight seal.

When too much headspace is left, all the air may not vent from the jar during processing, preventing the formation of a vacuum seal.

The type of food being canned determines the amount of headspace. See Step-by-Step.

What is the best way to keep pickles crispy and crunchy?

Ball 100% Natural Pickle Crisp ensures your pickles don’t turn out wimpy. Simply add Pickle Crisp directly into each jar of pickles and process according to a tested recipe like those on this web site. Pickle Crisp works with any fresh-pack pickle or pickled vegetable recipe. So try Pickle Crisp with you favorite pickle recipe!

What processing methods are recommended for home canned foods?

There are only two methods for heat processing home canned foods that are considered safe: the boiling-water method for high-acid foods and steam-pressure method for low-acid foods. These methods are outlined on this site. See Canning Basics.

It is also essential to use the correct processing time. For up-to-date recipes indicating the correct processing time, see Recipes. Although some people may continue to use outdated methods, these practices are not safe and should not be used for any reason. If you have a recipe or instructions using a method not listed here, that information should be replaced with up-to-date recipes and guidelines.

What type of equipment should I look for if I’m just getting started in home canning?

It is always best to use home canning jars and two-piece vacuum caps, boiling-water canner and steam-pressure canner that are described on this site. Ball® home canning products and Kerr® home canning line have a wide variety of jar sizes and closures to make home canning easy and safe. See Products.

Old jars and closures have a nostalgic appeal many people like; however, they are not considered the best type of jars and closures for home canning. Jars requiring a zinc cap and jar rubber or jars requiring a glass lid, wire bail, and jar rubber have not been recommended since 1989. There is no definitive way to determine if a vacuum seal has formed. This is one reason why the two-piece vacuum cap is superior to older style closures.

Today there are only two recommended methods for safe processing of home canned foods. When considering the type of canner to use, follow the guidelines in Canning Basics or Step-by-Step.

Older style canners may be functional, but they should be checked to determine if they meet today’s standards for processing foods. Particular attention must be given to steam-pressure canners to ensure their safety and accuracy. Refer to the manufacturer for more information on the use, safety and accuracy of older steam-pressure canners.

When cooked jams or jellies prepared with liquid fruit pectin do not set, how can they be fixed?

Before attempting to remake a jam, jelly or other fruit spread made with liquid fruit pectin, wait up to two weeks to determine if the product will gel. Not all recipes set within 24 hours. If after two weeks the product does not have a good set, it can be re-cooked in order to achieve a firmer texture.

Measure the unset product to be re-cooked. Prepare only a single batch at one time. For each quart of unset product, measure 3⁄4 cup sugar, 2 tablespoons lemon juice and 2 tablespoons liquid pectin, set aside. Place one quart of unset product into a medium saucepan and bring to boiling over medium-high heat. Quickly add the sugar, lemon juice and liquid pectin; bring to a rolling boil, stir constantly. Boil mixture hard for 1 minute. Remove from heat, skim foam if necessary. Carefully ladle hot mixture into hot jars, leaving 1⁄4-inch headspace. Adjust new lid and band on jar. Process in a boiling-water canner for the full length of time indicated in the original recipe.

When cooked jams or jellies prepared with powdered fruit pectin do not set, how can they be fixed?

Before attempting to remake a jam, jelly or other fruit spread made with powdered fruit pectin, wait up to two weeks to determine if the product will gel. Not all recipes set within 24 hours. If after two weeks the product does not have a good set, it can be re-cooked in order to achieve a firmer texture.

Measure the unset product to be re-cooked. Prepare only a single batch at one time. For each quart of unset product, measure 1/4 cup sugar, 4 teaspoons powdered fruit pectin, and 1/4 cup water, set aside. Combine pectin and water in a medium saucepan and bring to a boil over medium-high heat, stirring constantly to prevent scorching. Add the unset product and sugar. Stir thoroughly. Return to a rolling boil, stirring constantly. Boil hard for 30 seconds. Remove from heat, skim foam if necessary. Carefully ladle hot mixture into hot jars, leaving 1/4-inch headspace. Adjust new lid and band on jar. Process in a boiling-water canner for the full length of time indicated in original recipe.

How should I store home canned foods?

The ideal temperature range to store home canned foods is between 50° and 70°F. Food stored at temperatures higher than 70°F may lose some of its nourishing qualities. Freezing temperatures can cause the contents of a jar to freeze and expand, which in turn can break the seal or the jar.

When choosing where to store canned food in your home, make sure to avoid areas near furnace ducts, hot water pipes, stoves, hot water heaters or furnaces. Avoid uninsulated areas of your home that may be exposed to extreme hot and cold temperatures that would not be appropriate for canned food storage.

Be certain the area you select to store your home canned foods is a dry location. Damp locations can cause closures to corrode.

Since light hastens oxidation and destroys certain vitamins, a dark storage area is preferred. Light can also cause certain foods to fade in color. How you store canned food is as important as where. Placing filled jars in cupboards or boxes protects them from light. Wrapping the jars in newspapers and protecting the boxes with blankets can help protect them from freezing.

Why do home canned pickles lose their crunchy texture?

There are several factors that may cause a soft pickle:

  • Using a vinegar with an acidity level that is less than 5%;
  • Pickles were not processed or not processed long enough in a boiling-water canner to destroy spoilage microorganisms;
  • Variety of cucumber used;
  • Brine was too weak when fermenting cucumbers;
  • Cucumbers were not completely covered with brine while fermenting;
  • Cucumbers were not completely covered with liquid when packed in the jar;
  • Scum was not removed from top of brine while fermenting;
  • Improper storage or handling of cucumbers before pickling.

For detailed information on proper processing procedures, see Step-by-Step.

Why is it necessary to heat process home canned foods?

"Processing" or "heat processing" home canned foods is necessary to destroy all the microorganisms that could cause food spoilage and to vent air from the jar in order for a vacuum seal to form. Processing filled jars at the correct temperature and for the correct length of time will ensure the product is safe to store on the shelf.

Why is it necessary to add bottled lemon juice or citric acid to some home canned tomato recipes? Must the lemon juice be bottled lemon juice?

Tomatoes have a pH (acid) level that is just above the line dividing high-acid foods and low-acid foods. It is important for the safety and quality of tomato recipes that the proper acid level is maintained. Since many factors can decrease the natural acidity in tomatoes, the addition of bottled lemon juice or citric acid helps ensure the correct acidification. Bottled lemon juice must be used because its acid level is consistent, unlike fresh lemons.

Recipes that include an adequate amount of vinegar (5% acidity) do not require additional acidification, such as salsa, tomato chutney, and pickled tomatoes.

Always follow a tested recipe. Do not alter the type of ingredients in the recipe or the amount used. For up-to-date recipes, see Recipes.

How do I check to ensure my soft spread made without the use of commercial pectin will form a gel?

There are three tests you can perform to ensure your soft spread made without the use of commercial pectin has reached the gel stage.

Temperature Test: Cook the soft spread until it reaches a temperature of 220°F, or 8°F above the boiling point of water. Measure the temperature of soft spreads with a candy or jelly thermometer. Always insert the thermometer vertically into the soft spread and ensure that it does not contact the surface of the pot.

Sheet Test: Dip a cold metal spoon into the boiling soft spread. Lift the spoon and hold it horizontally with edge down so that the syrup runs off the edge. As the mixture cooks, the drops will become heavier and will drop off the spoon separately but two at a time. When the two drops join together and "sheet" off the spoon, the gel stage is reached.

Refrigerator Test: Chill two or three small saucers in the freezer. Place a teaspoonful of soft spread on the chilled saucer and place in the freezer for 1 minute. Remove the saucer from the freezer and push the edge of the spread with your finger. A mixture that has reached the gel stage will be set, and the surface will wrinkle when the edge is pushed. Note: To prevent overcooking or scorching, remove the soft spread from the heat before performing this test.

If the test you performed shows that the gel stage has not been reached, return the mixture to the heat to cook for a few minutes longer, then retest the soft spread.