Can You Pressure Can Bones? A Deep Dive into Safe and Effective Bone Processing

The question of whether you can pressure can bones often arises among homesteaders, survivalists, and culinary adventurers eager to maximize resource utilization and preserve food safely. The short answer is yes, you can pressure can bones, but there are crucial considerations and precise methods that must be followed to ensure safety and a palatable final product. This comprehensive guide will delve into the ‘hows’ and ‘whys’ of pressure canning bones, covering safety protocols, bone selection, processing techniques, and potential uses for your home-canned bone products.

Table of Contents

Understanding the Science Behind Pressure Canning Bones

Pressure canning is the only safe method for preserving low-acid foods, including bones, because it reaches temperatures high enough to kill Clostridium botulinum spores, the bacteria responsible for botulism. These spores thrive in anaerobic (oxygen-free) environments like sealed jars. Boiling water bath canning, which relies on lower temperatures, is insufficient for eliminating this risk in low-acid foods.

Bones themselves, while not directly harboring botulism spores, are embedded within meat and marrow, which are both low-acid and potential breeding grounds for these dangerous microorganisms. Therefore, the high heat and pressure achieved during pressure canning are essential for sterilization and safe long-term storage.

Why Pressure Canning is Essential

Unlike other canning methods, pressure canning creates a superheated environment within the canner. This allows the internal temperature of the food to reach 240°F (116°C) or higher. This temperature is maintained for a specific duration based on the food density, jar size, and altitude. This sustained high heat effectively eliminates botulism spores and other harmful bacteria, making the food safe to consume even after months or years of storage.

The Role of Acidity in Food Preservation

Acidity plays a critical role in preventing botulism. High-acid foods, like fruits and pickles, can be safely processed using boiling water bath canning because the acidic environment inhibits the growth of Clostridium botulinum. However, bones, meat, and most vegetables are low-acid, creating a favorable environment for these bacteria to flourish unless subjected to the intense heat of pressure canning.

Preparing Bones for Pressure Canning

Proper preparation is paramount for a successful and safe bone canning experience. This involves selecting the right types of bones, cleaning them thoroughly, and considering pre-processing methods like roasting or simmering.

Selecting the Right Bones

Not all bones are created equal when it comes to canning. The best bones for pressure canning are those rich in marrow and collagen.

Beef Bones: Beef bones, particularly marrow bones, knuckle bones, and oxtail, are excellent choices. They provide a rich flavor and high gelatin content, which contribute to a desirable texture and nutritional value.
Pork Bones: Pork hocks, neck bones, and ham bones are also good options. They impart a distinct flavor and collagen content.
Poultry Bones: Chicken and turkey carcasses, including necks and backs, can be pressure canned, though they generally yield a lighter broth and less marrow.
Fish Bones: While less common, fish bones can be pressure canned to create fish broth. However, it’s crucial to use only fresh, high-quality fish and to be mindful of potential histamine development, which can cause scombrotoxin fish poisoning if the fish isn’t handled and processed correctly. Special care should be taken in their preparation to remove all scales and entrails.

Avoid using bones from animals that may have been treated with antibiotics or hormones unless you are certain of their source and quality.

Cleaning and Pre-Processing Bones

Thorough cleaning is essential to remove any dirt, blood, or debris from the bones. Rinse the bones under cold running water and scrub them with a stiff brush. For larger bones, you may need to cut them into smaller pieces to fit into the canning jars.

Pre-processing can enhance the flavor and texture of your canned bone products. Two common methods are:

Roasting: Roasting the bones before canning develops a richer, deeper flavor. Spread the bones in a single layer on a baking sheet and roast them in a preheated oven at 400°F (200°C) for 30-60 minutes, or until they are nicely browned.
Simmering: Simmering the bones in water with aromatics like onions, carrots, and celery before canning extracts flavor and collagen. This can result in a more flavorful and nutritious bone broth. Simmer for several hours, then strain the broth and remove any meat scraps from the bones.

Preparing Jars and Lids

Proper jar preparation is critical for a successful canning outcome. Use canning jars specifically designed for pressure canning. Inspect the jars for any cracks, chips, or other damage, and discard any that are compromised.

Wash the jars in hot, soapy water and rinse them thoroughly. You can also sterilize the jars by boiling them in water for 10 minutes. Keep the jars hot until you are ready to fill them.

Prepare the lids according to the manufacturer’s instructions. Typically, this involves simmering the lids in hot water to soften the sealing compound. Do not boil the lids.

The Pressure Canning Process: Step-by-Step

The pressure canning process requires meticulous attention to detail to ensure safety and a high-quality final product.

Filling the Jars

Pack the prepared bones into the hot jars, leaving 1 inch of headspace. Headspace refers to the space between the top of the food and the lid of the jar. This space is necessary for proper sealing during the canning process.

If you are adding broth to the jars, pour it over the bones, ensuring that they are fully submerged. Remove any air bubbles by running a non-metallic spatula or bubble remover along the inside of the jar.

Wipe the jar rims with a clean, damp cloth to remove any food particles or residue. This is essential for achieving a proper seal.

Place the lids on the jars and screw on the bands finger-tight. Do not overtighten the bands, as this can prevent the jars from venting properly during processing.

Loading and Operating the Pressure Canner

Follow the manufacturer’s instructions for your specific pressure canner model. Generally, this involves:

Adding the specified amount of water to the canner.
Placing the filled jars on the rack inside the canner, ensuring that they do not touch each other or the sides of the canner.
Locking the canner lid securely in place.
Turning on the heat to medium-high.
Allowing the canner to vent steam for 10 minutes to remove air from the canner.
Placing the weighted gauge or closing the petcock, depending on your canner type.
Monitoring the pressure gauge and adjusting the heat to maintain the required pressure for the specified processing time.
Once the processing time is complete, turn off the heat and allow the canner to cool naturally. Do not force-cool the canner, as this can cause the jars to crack or the food to spoil.
Once the pressure has returned to zero, carefully remove the lid and allow the jars to cool for 10 minutes before removing them from the canner.

Processing Times and Pressures

Processing times and pressures vary depending on the type of bones, jar size, and altitude. Always consult a reputable canning guide, such as the USDA Complete Guide to Home Canning or publications from your local extension office, for specific recommendations.

As a general guideline, the following processing times and pressures are recommended for canning bones:

Important Note: Adjust the pressure according to your altitude. For altitudes above 2,000 feet, increase the pressure by 1 PSI for every 1,000 feet of elevation.

Cooling and Storing the Canned Bones

After removing the jars from the canner, place them on a towel-lined surface and allow them to cool completely for 12-24 hours. As the jars cool, you should hear a popping sound as the lids seal.

Once the jars are cool, check the seals by pressing down on the center of the lid. If the lid does not flex, the jar is properly sealed. If the lid flexes, the jar is not sealed and should be reprocessed or refrigerated and used within a few days.

Remove the bands from the sealed jars and wash the jars with soap and water. Label the jars with the date and contents and store them in a cool, dark, and dry place. Properly canned bones can be stored for up to a year or longer.

Using Your Home-Canned Bones

Home-canned bones offer a versatile base for various culinary applications. The rich broth and tender marrow can be used to enhance soups, stews, sauces, and other dishes.

Bone Broth

The liquid from the canned bones is essentially bone broth, a nutrient-rich elixir celebrated for its health benefits. Bone broth is a good source of collagen, gelatin, and minerals like calcium, phosphorus, and magnesium.

It can be consumed on its own as a warm beverage or used as a base for soups and stews. The gelatin in bone broth adds a silky texture and richness to dishes.

Marrow Extraction

The marrow inside the canned bones becomes incredibly tender and easily extracted. Marrow is a nutritional powerhouse, rich in healthy fats, vitamins, and minerals.

It can be spread on toast, added to sauces, or used to enrich soups and stews. The marrow provides a distinctive flavor and creamy texture.

Enhancing Soups, Stews, and Sauces

Canned bones can be added directly to soups, stews, and sauces to enhance their flavor and nutritional value. The bones will continue to release collagen and minerals into the liquid as they simmer, creating a richer and more flavorful dish.

Troubleshooting Common Issues

Even with careful planning and execution, canning can sometimes present challenges. Here are some common issues and how to address them:

Siphoning: Siphoning occurs when liquid is lost from the jars during processing. This can be caused by overcrowding the jars in the canner, fluctuating pressure, or removing the jars from the canner too quickly. Ensure proper headspace, maintain consistent pressure, and allow the canner to cool completely before removing the jars to minimize siphoning.
Jar Breakage: Jar breakage can occur due to thermal shock or pressure imbalances. Use canning jars specifically designed for pressure canning, avoid sudden temperature changes, and ensure that the pressure canner is properly vented and operated.
Seal Failure: Seal failure can be caused by improper jar preparation, inadequate headspace, or damaged lids. Inspect the jars for cracks and chips, ensure proper headspace, and use new lids for each canning batch.
Off-Flavors: Off-flavors can be caused by using poor-quality ingredients, insufficient processing time, or improper storage. Use fresh, high-quality bones, follow recommended processing times and pressures, and store the canned bones in a cool, dark, and dry place.

Safety Precautions: A Crucial Reminder

Pressure canning involves high temperatures and pressures, so safety should always be your top priority.

Always follow a reputable canning guide: Consult the USDA Complete Guide to Home Canning or publications from your local extension office for detailed instructions and recommended processing times and pressures.
Use a pressure canner: Do not attempt to pressure can bones in a boiling water bath canner, as this is not safe.
Inspect your equipment: Regularly inspect your pressure canner and jars for any signs of damage.
Maintain consistent pressure: Monitor the pressure gauge and adjust the heat to maintain the required pressure throughout the processing time.
Allow the canner to cool naturally: Do not force-cool the canner, as this can cause the jars to crack or the food to spoil.
Check the seals: After the jars have cooled, check the seals to ensure that they are properly sealed.
If in doubt, throw it out: If you are unsure about the safety of a canned product, discard it.

Conclusion: Embracing Safe and Sustainable Bone Canning

Pressure canning bones is a rewarding and sustainable way to utilize valuable resources and create nutritious and flavorful food. By understanding the science behind pressure canning, following proper preparation techniques, and adhering to strict safety protocols, you can safely and effectively preserve bones for a variety of culinary applications. Embrace the art of bone canning and unlock a world of culinary possibilities while ensuring the safety and well-being of yourself and your loved ones. Remember, meticulous attention to detail and a commitment to safety are paramount for a successful and enjoyable bone canning experience.

FAQ 1: Is it safe to pressure can bones to make them edible?

It is generally unsafe to attempt to make bones fully edible through pressure canning. While the high heat and pressure can soften bones, making them more palatable, they are unlikely to become completely digestible. Furthermore, the structural integrity of larger bones can remain, presenting a choking hazard even after prolonged pressure canning. The primary concern is the potential for shards and splinters, which could cause injury to the digestive tract.

Pressure canning bones can, however, be a useful technique for extracting nutrients and creating bone broth. The process helps break down the collagen in the bones, releasing gelatin, minerals, and other beneficial compounds into the liquid. While you won’t be eating the bones themselves, you’ll be consuming a nutrient-rich broth that can be used in soups, sauces, and other dishes. Remember to strain the broth thoroughly to remove any bone fragments.

FAQ 2: What types of bones are best suited for pressure canning into bone broth?

The best types of bones for pressure canning into bone broth are those rich in collagen and marrow. These include beef knuckles, femurs, and oxtails, as well as chicken necks, backs, and feet. Pork bones, such as trotters or ham hocks, can also be used effectively. The variety of bones can contribute to a richer, more complex flavor in the resulting broth.

Avoid using bones from fish or small birds, as they tend to be too delicate and can disintegrate during the pressure canning process. Also, be cautious with bones from older animals, as they may be less yielding and contain fewer nutrients. Always source your bones from reputable suppliers to ensure they are of good quality and free from any potential contaminants.

FAQ 3: What are the safety precautions to take when pressure canning bone broth?

When pressure canning bone broth, strict adherence to safety guidelines is crucial to prevent botulism and other foodborne illnesses. First, thoroughly clean and prepare your pressure canner according to the manufacturer’s instructions. Ensure the vent pipes and safety valves are clear and functioning properly. Use only tested recipes and processing times from reliable sources like the USDA or your local extension office.

Pack the jars loosely, leaving the recommended headspace to allow for expansion during processing. Process the jars for the correct duration and pressure according to your altitude and the jar size. After processing, allow the canner to depressurize naturally. Once cool, check the seals on the jars to ensure they are properly sealed. Any jars with unsealed lids should be refrigerated immediately and consumed within a few days or reprocessed.

FAQ 4: How long should I pressure can bone broth?

The processing time for pressure canning bone broth varies depending on the type of bones, jar size, and your altitude. It is essential to consult a reliable canning resource, such as the USDA Complete Guide to Home Canning, for specific instructions. Generally, for quarts, beef or pork bone broth requires longer processing times than chicken broth.

As a general guideline, for beef or pork bone broth in quart jars, you might need to process for approximately 25 minutes at 10 PSI for altitudes at or below 1,000 feet. For altitudes above 1,000 feet, the pressure may need to be increased. Always adjust processing times according to your altitude to ensure adequate heat penetration and prevent spoilage. Remember, under-processing can lead to serious health risks.

FAQ 5: How do I know if my pressure-canned bone broth has spoiled?

There are several signs that indicate your pressure-canned bone broth has spoiled. The most obvious is a bulging lid, which suggests gas production inside the jar due to microbial activity. Another warning sign is a broken seal. If the lid is loose or can be easily lifted off, the jar has not properly sealed and the contents may be contaminated.

Upon opening the jar, look for signs of mold growth, discoloration, or unusual odors. If the broth has an off-putting smell or appears cloudy or slimy, it should be discarded immediately. It is also important to listen for a forceful hiss of air when opening the jar, as this indicates a vacuum seal. If there is no hiss, the seal may have been compromised. When in doubt, it is always best to err on the side of caution and discard any questionable broth.

FAQ 6: Can I add vegetables to my bone broth before pressure canning?

Adding vegetables to your bone broth before pressure canning can alter the density and acidity of the mixture, which can affect the processing time required to ensure safety. While it is possible to add some vegetables, it is crucial to follow tested recipes that specify the type and quantity of vegetables that can be safely included. Adding too many vegetables, particularly low-acid vegetables like carrots and celery, can increase the risk of botulism.

If you choose to add vegetables, it is recommended to use non-starchy vegetables such as onions, garlic, and herbs in small quantities. Avoid adding thickeners like flour or cornstarch, as they can interfere with heat penetration. For maximum safety, consider pressure canning the bone broth separately and adding fresh vegetables when you use the broth in your recipes. This allows for more precise control over the ingredients and reduces the risk of spoilage.

FAQ 7: What is the best way to store pressure-canned bone broth?

Proper storage is essential to maintain the quality and safety of pressure-canned bone broth. Once the jars have cooled completely and you have verified that the seals are intact, store them in a cool, dark, and dry place. Ideal storage conditions are a temperature between 50°F and 70°F. Avoid storing jars in direct sunlight or near sources of heat, as this can cause the contents to degrade.

Label each jar with the date it was canned so you can easily track its age. Properly canned bone broth can typically be stored for up to a year, although it is best to use it within six months for optimal flavor and nutritional value. After opening a jar, refrigerate any unused portion immediately and consume it within a few days. Discard any leftover broth that has been stored for more than a week.