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Does putting fruit in mason jars really work?

Putting fruit in mason jars, also known as canning or preserving fruit, is a time-honored technique for enjoying fruit out of season. The process involves heating fruit that has been packed into sterile jars, creating a vacuum seal, and allowing the jars to cool and set. This prevents spoilage by killing microorganisms and enzymes that would otherwise cause the fruit to degrade over time. When done properly, canning fruit in mason jars can keep for up to a year or longer.

Benefits of Canning Fruit

There are several advantages to canning fruit in mason jars:

  • Enjoy fruit out of season – Canning allows you to enjoy fruits like peaches, cherries, and berries during the winter months when they are not in season.
  • Preserve a bumper crop – When you grow or buy a lot of fruit at peak season, canning preserves the bounty to eat later.
  • Control ingredients – Unlike store-bought canned fruit, you control the amount of sugar, spices, and other ingredients when you can fruit yourself.
  • Save money – Canning your own fruit is cheaper than buying commercially canned fruit.
  • Make great gifts – Homemade canned fruit makes a thoughtful, unique gift for others.
  • Enjoy better taste – The flavor and texture of home-canned fruit is superior to store-bought canned fruit.

The benefits of canning fruit are plentiful. Enjoying the fresh taste of fruit long after the growing season, controlling added sugars and preservatives, and saving money are just a few of the reasons why people have been canning fruit at home for generations.

Does Canning Fruit Really Work?

So does the process of canning fruit in mason jars actually work to prevent spoilage? The short answer is yes – when done correctly, canning fruit is an extremely effective method for food preservation. There are several keys to successful canning:

  • Use proper canning equipment – A water bath canner or pressure canner is required to safely can fruit. The jar lids and rings should be in good condition. Only use mason jars specifically designed for home canning.
  • Use an approved recipe – Evidence-tested canning recipes ensure the fruit is heated to a temperature that destroys spoilage microorganisms. Always use recipes from trusted sources like the USDA.
  • Acidify the fruit – Adding lemon juice, citric acid, or vinegar helps create the acidic conditions needed to prevent the growth of dangerous bacteria like botulism. Acidification is especially important when canning low-acid foods like figs, apples, or pears.
  • Process jars properly – Processing times and methods vary depending on the type of fruit, method of canning, and jar size. Closely following processing instructions kills microorganisms and creates an airtight seal.
  • Allow seals to set – Leave space between jars as they cool undisturbed for 12-24 hours. This allows the vacuum seals to fully set.
  • Inspect seals and headspace – Before storing, check that jar lids are concave and do not move when pressed. Headspace between the lid and fruit should match recipe guidelines.
  • Handle jars carefully – Avoid bumping or jostling sealed jars. Refrigerate after opening. Look for signs of spoilage before eating.

Following proper canning procedures allows you to store home-canned fruit for up to a year. If jars lose their seal or show signs of mold, bacteria, or other spoilage, they should be discarded.

Fruit Canning Methods

There are two main methods that can be used at home to safely can fruit – the boiling water bath method and the pressure canner method.

Boiling Water Bath Canning

This technique submerges sealed jars in boiling water for a set period of time.

  • Typically used for high-acid fruits like berries, citrus, stone fruits, pears, and apples
  • Does not achieve temperatures high enough to safely can low-acid foods
  • Requires acidifying fruit with lemon juice, citric acid, or vinegar
  • Processing times range from 15-30 minutes depending on fruit type and jar size

This simple method works well for fruits that are naturally high in acid. Always use evidence-based processing times to ensure safety.

Pressure Canner Canning

Pressure canning allows jars to be heated under pressure above the boiling point of water.

  • Used for canning low-acid fruits, vegetables, meats, and other foods
  • Achieves temperatures up to 240°F to destroy spores that can survive boiling water temperatures
  • Requires specially designed pressure canner with rack, regulator, and gauges
  • Processing times typically range from 10-25 minutes depending on the food’s density

Pressure canning is the only safe method for canning low-acid foods like figs, quince, tomatoes, pumpkin, avocado, and some tropical fruits. Always follow manufacturer’s instructions.

Fruits That Can Be Canned

Many types of fruits can be successfully preserved through water bath or pressure canning. Some examples include:

Fruit Canning Method
Apples Boiling water bath
Apricots Boiling water bath
Blackberries Boiling water bath
Blueberries Boiling water bath
Cherries Boiling water bath
Cranberries Boiling water bath
Figs Pressure canner
Grapefruit Boiling water bath
Peaches Boiling water bath
Pears Boiling water bath
Plums Boiling water bath
Raspberries Boiling water bath
Rhubarb Boiling water bath
Strawberries Boiling water bath

This table shows just a sampling of the fruits that can be canned in boiling water or a pressure canner when proper technique is used. Always start with high-quality fresh fruit free of bruises or mold.

Tips for Canning Fruit

Follow these tips for delicious, safe home-canned fruit:

  • Use ripe but firm fresh fruit
  • Wash and peel fruit, removing stems, pits, etc.
  • Work in small batches to keep fruit from oxidizing
  • Use a light syrup of 1 part sugar to 4 parts water for sweetness
  • Leave proper headspace as specified in recipes
  • Remove air bubbles by sliding a non-metallic utensil around the inside of the jar
  • Wipe jar rims to ensure a good seal
  • Process for the full time indicated in recipes
  • Label jars with contents and processing date
  • Store jars in a cool, dark place
  • Refrigerate after opening and use within a few weeks

Adhering to these best practices will help you create delicious canned fruit that stays fresh for up to a year when stored properly.

Common Problems When Canning Fruit

While canning fruit at home is generally safe when guidelines are followed, there are some potential problems to be aware of:

  • Improper seal – If jar lids don’t properly seal, fruit will quickly spoil. Check seals after cooling completely.
  • Loss of liquid – If jars lose liquid over time, fruit can oxidize, creating discoloration, off-flavors, and mushy texture.
  • Mold – If seals fail, mold can grow in the jars. Discard immediately if mold is observed.
  • Fermentation – Yeasts and bacteria can cause fermentation, bulging lids, sliminess, gas or fizzing. Toss fermented jars.
  • Surface bacterial growth – Harmless but unappetizing white, yellow or black spots of yeast or bacterial growth can occur if fruit wasn’t cleaned well.
  • Jar breakage – Jars may crack or break during processing if lime deposits build up in the canner or jars were placed on a cold surface after removal. A damaged jar compromises the seal.

While disconcerting when they happen, most common canning issues are easily avoided by carefully following fruit canning best practices for preparation, sterilization, and processing.

Safety Tips for Canning Fruit

To keep your home-canned fruit safe, be sure to:

  • Use up-to-date tested canning recipes and follow instructions precisely
  • Check headspace and verify proper seals before storing
  • Never eat from bulging, damaged, cracked, or unsealed jars
  • Boil low-acid foods like figs for the full time recommended for your altitude
  • Clean jar rims and lids thoroughly and sterilize all equipment
  • Store jars in a cool, dark place between 50-70°F
  • Refrigerate after opening and consume within days
  • Label jars with contents and date to use within 1 year

Adhering to safe home canning guidelines, using quality equipment, and choosing acidic fruits will help keep your canned goods safe to enjoy for many months to come.

Conclusion

Canning fruit in mason jars is an extremely effective way to enjoy the bounty of fruit harvests long after the season has ended. When done properly using safe, approved recipes and meticulous sterilization methods, fruit canned in mason jars will keep for up to a full year. The boiling water bath process is perfect for high-acid fruits while pressure canning allows low-acid options to be safely preserved as well. Follow proper guidelines carefully, choose ripe, fresh fruits, prep and clean thoroughly, process using trusted methods and times, and make sure lids seal correctly. With some care and planning, you can enjoy delicious home-canned fruits all year long.