Home canning, the art of preserving food in glass jars, is a time-honored tradition that offers a delicious and rewarding way to enjoy seasonal produce year-round. But what exactly can you jar? The possibilities are vast, but understanding the science behind safe canning is crucial to prevent spoilage and ensure food safety.
Understanding the Basics of Safe Canning
Before diving into specific foods, it’s essential to grasp the fundamentals of safe canning. Proper canning techniques eliminate microorganisms that can cause spoilage and create a vacuum seal to prevent new ones from entering. The key lies in controlling acidity levels.
High-acid foods, like fruits, jams, jellies, pickles, and some tomatoes, can be safely processed in a boiling water bath canner. The high acidity inhibits the growth of harmful bacteria.
Low-acid foods, such as vegetables, meats, poultry, and seafood, require a pressure canner. This is because Clostridium botulinum, the bacteria that produces botulism toxin, can survive in low-acid environments at boiling water temperatures. The higher temperatures achieved in a pressure canner destroy these spores.
It is always imperative to follow tested recipes from reliable sources like the USDA Complete Guide to Home Canning, university extension services, or reputable canning books. Modifying recipes can alter the acidity level and compromise safety.
Fruits: Sweet Preserves for Every Season
Fruits are among the most popular items to can, offering a delightful way to capture the flavors of summer and autumn.
Jams, Jellies, and Preserves
Jams, jellies, and preserves are classic canned goods, made by cooking fruit with sugar and pectin until thickened. Berries (strawberries, blueberries, raspberries), stone fruits (peaches, plums, apricots), and apples are all excellent choices.
High sugar content in these products acts as a preservative, making them safe for boiling water bath canning. Using commercially prepared pectin ensures proper gelling.
Fruit Butters
Fruit butters, such as apple butter, pumpkin butter, and pear butter, are smooth, spreadable fruit purees cooked down until thick and intensely flavored. These often require longer processing times due to their density.
Proper stirring during cooking is crucial to prevent scorching, and accurate head space measurement is important when filling jars.
Canned Fruits in Syrup
Canning fruits in syrup involves packing prepared fruit pieces into jars and covering them with a hot syrup solution. The syrup helps to preserve the fruit’s color and flavor. Peaches, pears, apples, and cherries are commonly canned this way.
The density of the syrup (light, medium, or heavy) can be adjusted to suit personal preferences.
Fruit Pie Fillings
While convenient, canning pie fillings requires a specific recipe and thickener (often Clear Jel) to ensure safe processing. The thickener binds the liquids and prevents uneven heating during processing.
Do not substitute other thickeners for Clear Jel in these recipes.
Vegetables: Bringing the Garden Indoors
Canning vegetables allows you to enjoy your garden’s bounty throughout the year, but it requires careful attention to detail and the use of a pressure canner for most varieties.
Tomatoes: A Canned Staple
Tomatoes are a versatile vegetable (though technically a fruit!) that can be canned in various ways. They can be crushed, diced, juiced, or made into sauce.
Adding an acid (lemon juice, citric acid, or vinegar) is crucial to ensure a safe pH level, even for naturally acidic tomatoes. This is because some tomato varieties are borderline in terms of acidity.
Pickled Vegetables: Tangy and Crunchy
Pickling is a popular method of preserving vegetables by immersing them in a brine of vinegar, water, and spices. Cucumbers (for pickles), green beans (for dilly beans), beets, and carrots are excellent candidates for pickling.
The high acidity of the vinegar acts as a preservative. Following tested recipes is important to ensure the correct vinegar-to-water ratio.
Other Vegetables
Green beans, corn, peas, carrots, and potatoes can all be canned, but only using a pressure canner. Always follow tested recipes and processing times for each specific vegetable.
Never add thickeners like flour or cornstarch to vegetable canning recipes, as they can interfere with heat penetration.
Meats, Poultry, and Seafood: Preserving Protein
Canning meats, poultry, and seafood requires strict adherence to tested recipes and the use of a pressure canner. These foods are low-acid and require high temperatures to eliminate the risk of botulism.
Beef, Pork, and Lamb
Beef, pork, and lamb can be canned as stew meat, ground meat, or roasts. Pre-cooking the meat before canning is often recommended.
Pack the jars loosely to allow for proper heat penetration.
Poultry
Chicken and turkey can be canned as whole pieces, chunks, or ground meat. Remove the bones for safer and more efficient canning.
Skin should also be removed, as it can hinder heat penetration and affect the quality of the canned product.
Seafood
Fish like tuna, salmon, and sardines can be canned at home, but it requires careful attention to detail. Follow tested recipes and processing times precisely.
Consider the oil content of the fish, as it can affect processing times.
Other Foods Suitable for Canning
Beyond fruits, vegetables, and meats, there are other foods that can be safely preserved through canning.
Stocks and Broths
Homemade stocks and broths can be canned in a pressure canner, providing a convenient base for soups and sauces.
Remove excess fat before canning to improve the quality and safety of the product.
Soups
Canning soups is possible, but it’s important to follow tested recipes and guidelines. Soups containing meat, poultry, or seafood require pressure canning. Soups with high-acid ingredients and no meat can be water bath canned.
Avoid adding pasta or noodles before canning, as they can become mushy and affect heat penetration. Add these ingredients when you reheat the soup.
Salsas and Sauces
Salsas and sauces, such as tomato sauce, pasta sauce, and barbeque sauce, can be canned, offering a convenient way to preserve your favorite flavors.
Adjust the acidity as needed by adding lemon juice or vinegar, especially for tomato-based sauces.
Essential Equipment for Canning
Having the right equipment is crucial for safe and successful canning.
- Canning jars: Use jars specifically designed for canning, with two-piece lids (flat lid and screw band).
- Boiling water bath canner or pressure canner: Choose the appropriate canner based on the acidity of the food you are canning.
- Jar lifter: A jar lifter is essential for safely lifting hot jars from the canner.
- Lid wand: A magnetic lid wand helps to retrieve lids from hot water.
- Wide-mouth funnel: A wide-mouth funnel makes it easier to fill jars without spilling.
- Bubble remover/headspace tool: This tool helps to remove air bubbles from jars and measure headspace.
Tips for Successful Canning
- Use only tested recipes from reliable sources.
- Follow instructions carefully and do not deviate from the recipe.
- Prepare jars and lids according to the manufacturer’s instructions.
- Fill jars correctly, leaving the appropriate amount of headspace.
- Remove air bubbles from jars before sealing.
- Process jars for the correct time according to the recipe.
- Check seals after processing to ensure a proper vacuum.
- Store canned goods in a cool, dark, and dry place.
- Label jars with the date and contents.
- Consume canned goods within one year for best quality.
Foods to Avoid Canning at Home
While many foods can be safely canned, some are not recommended for home canning due to safety concerns or quality issues.
- Dairy products: Milk, cream, and cheese are not safe to can at home.
- Eggs: Whole eggs are not safe to can at home.
- Butter: Butter is difficult to can safely and the quality may suffer.
- Oils: Canning foods in oil is not recommended due to the risk of botulism.
- Thickened products: Adding thickeners like flour, cornstarch, or pasta to canning recipes can interfere with heat penetration and compromise safety, unless the recipe specifically allows it.
- Squash and pumpkin puree: Due to density and inconsistent heat penetration, canning pumpkin puree and other winter squashes are not recommended. Small cubes are a safer option.
Home canning is a rewarding skill that allows you to preserve the flavors of the seasons and enjoy homemade goodness year-round. By understanding the principles of safe canning and following tested recipes, you can confidently create a pantry full of delicious and safe canned goods. Remember, safety should always be your top priority when canning food at home.
What are the safest foods to can at home for beginners?
For novice home canners, high-acid foods are the safest and easiest to process. These include fruits like apples, berries, peaches, and pears, as well as jams, jellies, pickles, and tomatoes that have been properly acidified with lemon juice or vinegar. High-acid environments inhibit the growth of Clostridium botulinum, the bacteria that causes botulism, making them a more forgiving starting point for learning the canning process.
Choosing simple recipes with clear instructions and readily available ingredients is also beneficial. Starting with a small batch of fruit jam or a simple pickle recipe allows you to practice the canning techniques without committing to a large quantity of food. As you gain confidence and experience, you can gradually expand your repertoire to include more complex recipes and lower-acid foods, always adhering strictly to tested canning methods.
Why can’t I can just any recipe I find online?
Not all recipes found online are safe for canning because they may not provide the necessary level of acidity or processing time to eliminate harmful bacteria. Unsafe recipes can lead to spoilage and, more seriously, the production of toxins that cause botulism, a potentially fatal illness. It is crucial to rely on recipes from reputable sources that have been scientifically tested for safety.
Reputable sources, such as the USDA Complete Guide to Home Canning, university extension services (like the National Center for Home Food Preservation), and well-known canning equipment manufacturers (like Ball or Kerr), follow stringent guidelines for recipe development and testing. These sources ensure that the recipes provide adequate acidity and processing times to destroy harmful microorganisms, guaranteeing the safety of the canned goods.
What is the difference between water bath canning and pressure canning?
Water bath canning involves submerging jars of food in boiling water for a specific amount of time. This method is suitable for high-acid foods like fruits, jams, jellies, pickles, and properly acidified tomatoes, where the high acidity prevents the growth of botulism spores. The boiling water reaches a temperature of 212°F (100°C), which is sufficient to kill molds, yeasts, and some bacteria in high-acid environments.
Pressure canning, on the other hand, uses a specialized pressure canner to create a higher temperature (240°F or 116°C) than can be achieved with boiling water. This higher temperature is necessary to kill Clostridium botulinum spores in low-acid foods like vegetables, meats, poultry, and seafood. Pressure canning is the only safe method for preserving these types of foods at home because it eliminates the risk of botulism.
How do I ensure proper headspace in my canning jars?
Headspace refers to the empty space between the top of the food in the jar and the lid. Proper headspace is crucial for creating a vacuum seal during the cooling process. Insufficient headspace can cause food to bubble out during processing, preventing a proper seal, while excessive headspace may lead to insufficient processing and potential spoilage.
Follow the recipe’s specific headspace recommendations, typically ranging from ¼ inch for jams and jellies to 1 inch for some vegetables. Use a headspace tool or a clean ruler to measure the space accurately. After filling the jars and before placing the lids, remove any trapped air bubbles by gently running a non-metallic utensil, like a plastic knife or spatula, around the inside of the jar. Wipe the jar rims clean before applying the lids and bands.
What are the signs of spoiled canned food?
Several signs indicate that canned food may be spoiled and should not be consumed. These include a bulging lid, which suggests the presence of gas produced by microbial growth. A broken seal, where the lid is not firmly attached or can be easily removed, is another clear warning sign. Spurting liquid upon opening the jar also indicates spoilage and potential contamination.
Other indications of spoilage include mold growth on the food or inside the jar, an unusual or foul odor upon opening, and an unnatural color or texture of the food. If any of these signs are present, discard the contents without tasting them. It is always better to err on the side of caution when dealing with potentially spoiled canned goods, as botulism poisoning can be severe and even fatal.
Can I reuse canning lids?
No, canning lids are designed for single-use only. The sealing compound on the underside of the lid is compressed during the canning process to create an airtight seal. Attempting to reuse a lid often results in an inadequate seal, increasing the risk of spoilage and contamination. While they might appear undamaged, the sealing compound may no longer be effective.
Canning bands, however, can be reused as long as they are not rusted or damaged. After processing and cooling the jars, the bands can be removed for storage, as they are not necessary for maintaining the seal. Using new, unused lids for each canning batch ensures the best possible chance of achieving a proper and safe seal, protecting the food from spoilage.
How long does canned food last?
Properly canned food, stored in a cool, dark, and dry place, can last for at least one year and often longer. While the food may remain safe to eat beyond one year, the quality may decline in terms of color, texture, and flavor. It’s best to consume home-canned goods within 12-18 months for optimal quality.
Always label your canned goods with the date of processing to keep track of their age. Regularly inspect your stored canned goods for any signs of spoilage, such as bulging lids, broken seals, or unusual odors. Even if the food appears and smells normal, it is best practice to consume older canned goods first to minimize the risk of quality degradation.