10 Unsafe Canning Recipes and Practices You Should Never Use

Unsafe canning recipes and practices can put you and your family at risk for foodborne illness, even if the jars seal properly. From canning butter and bread in jars to using outdated recipes or improper ingredients, many popular canning methods shared online haven't been tested for safety.

The good news is that once you understand the science behind safe home canning and know which recipes and methods to avoid, you can preserve your harvest with confidence. In this guide, I'll walk you through 10 unapproved or unsafe canning recipes and practices, explain why they aren't considered safe, and share what to do instead.

Home canning has experienced a huge resurgence over the past several years. More people than ever are growing their own food, preserving family recipes, and learning traditional skills that help build a well-stocked pantry.

Unfortunately, not everything shared online about canning is safe.

Social media has made it easy for anyone to publish recipes and tutorials, but a beautiful-looking jar with a sealed lid doesn't necessarily mean the food inside is safe to eat. In fact, some popular canning methods and recipes can put you at risk for foodborne illness, including botulism, a rare but potentially fatal toxin.

As someone who's been canning for more than 25 years, taught thousands of people how to preserve food safely, and written extensively about food preservation (including my own book, Everything Worth Preserving), I've seen many unsafe canning trends come and go. Some are old family recipes that were passed down without understanding the science behind them. Others are newer trends that have spread quickly through social media without ever being tested for home canning safety (such as whether you should can in an electric pressure cooker and the pros and cons of electric pressure canners).

The good news is that safe home canning doesn't have to be complicated. Once you understand a few key principles, like using tested recipes, maintaining proper acidity, and choosing the correct canning method, you can preserve food with confidence.

In this article, I'll walk you through ten common unsafe or unapproved canning recipes and practices, explain why they aren't considered safe, and share what to do instead. My goal isn't to discourage you from canning. It's to help you confidently fill your pantry with foods you know are safe for your family to enjoy.

Then, if you come across a recipe you're not sure of, check out my post on how to know if a canning recipe is safe.

1. Oven Canning (Including Bread and Cake in Jars)

One of the most common unsafe canning trends I've seen in recent years is oven canning. While this practice has been shared on social media and passed down through some families for generations, it isn't considered a safe method of food preservation.

A common variation of oven canning is baking bread or cake directly in a canning jar, placing the lid on while it's still hot, and storing it on the pantry shelf after the lid seals. While it may look successful because the lid seals, that seal alone doesn't tell you whether the food is safe to eat.

In home canning, a sealed jar simply means a vacuum formed as the contents cooled. It does not mean harmful bacteria have been destroyed or that the food inside is shelf stable.

Why Isn't Oven Canning Safe?

There are two major reasons oven canning isn't recommended.

First, dry heat doesn't transfer heat the same way boiling water or pressurized steam does. Water is an excellent conductor of heat, allowing food inside the jar to reach temperatures that have been tested for safe preservation. Air, on the other hand, transfers heat much less efficiently. Even if your oven is set to 350°F, the center of the food inside the jar may never reach a temperature high enough for safe preservation.

Second, there are no tested processing times for oven canning. Safe home canning relies on research that determines exactly how long a specific food must be processed at a specific temperature to destroy harmful microorganisms. Those tested times simply don't exist for oven-canned foods.

Why Bread and Cake Are Especially Risky

Bread and cake create another challenge because they're very dense foods.

For shelf-stable home canning, both acidity and heat penetration matter. Dense foods are much more difficult for heat to penetrate evenly, making it impossible to know whether the center of the jar has reached a safe temperature.

That's why you won't find any approved home canning recipes for bread or cake in jars from trusted testing organizations.

What to Do Instead

If you'd like to prepare baked goods ahead of time, there are much safer options.

• Bake bread and enjoy it fresh, then freeze extra loaves for later.
• Freeze cakes, muffins, or quick breads after they've cooled completely.
• Vacuum seal baked goods for freezer storage to help extend quality.

These methods preserve the texture and flavor far better than attempting to can them, while also keeping your family safe.

Bottom line: If you see bread, cake, or other baked goods being preserved in sealed canning jars at room temperature, skip the recipe. A sealed lid is never proof that a food has been safely canned. Always use tested home canning methods and approved recipes for shelf-stable food preservation.

2. Canning Butter and Dairy Products

If you've spent any time on social media, you've probably seen videos showing people canning butter to make it shelf stable. It's often promoted as a way to stock a long-term pantry, but despite how popular this trend has become, there are no approved home canning recipes for butter or other dairy products.

That's because safe home canning isn't just about getting a jar to seal. As I mentioned before, it's about ensuring the food has been processed long enough and at a high enough temperature to eliminate harmful bacteria and prevent the growth of botulism.

Why Butter Can't Be Safely Home Canned

Butter is primarily fat, and fat creates unique challenges during the canning process.

Unlike fruits, jams, or properly acidified foods, butter doesn't have the acidity needed for safe water bath canning. It also hasn't been tested for pressure canning, so there are no scientifically validated processing times that ensure the entire jar reaches a safe temperature.

Another issue is that fat can interfere with sealing. As butter melts during processing and solidifies again while cooling, it can leave residue along the rim of the jar or compromise the seal over time.

Even if a jar seals successfully, that doesn't mean the butter inside is safe for long-term pantry storage.

What About Other Dairy Products?

The same concerns apply to most dairy products, including milk, cream, cheese, and yogurt.

Not only are there no approved home canning recipes for these foods, but dairy also tends to separate, curdle, or develop an unpleasant texture when exposed to the high temperatures required for canning.

Even if safety weren't a concern, the finished product usually isn't something most people would enjoy using.

A Better Way to Store Butter

The good news is that butter freezes exceptionally well.

If you find butter on sale or purchase it in bulk, simply store the unopened packages in your freezer. Butter can maintain excellent quality for many months when frozen, allowing you to build a pantry reserve without compromising food safety.

When you're ready to use it, transfer a package to the refrigerator and thaw it overnight.

The Bottom Line

Just because someone online has canned butter for years without experiencing a problem doesn't mean the practice is safe. Home canning recommendations are based on tested research, not anecdotal experience.

If there isn't a scientifically tested recipe, there isn't a way to know whether the food has been processed safely. When it comes to butter and dairy products, the safest choice is simple: freeze them instead of canning them.

3. Pickled Eggs Should Never Be Home Canned

At first glance, pickled eggs seem like they should be perfectly safe for home canning. After all, they're packed in vinegar, and vinegar is acidic enough to prevent the growth of botulism in many pickled foods.

So why aren't there approved recipes for shelf-stable canned pickled eggs?

The answer comes down to one important factor: density.

Why Pickled Eggs Aren't Safe for Home Canning

For a food to be safely preserved using acidity, the acid has to penetrate all the way to the center of the food.

Eggs are extremely dense. While the vinegar brine can easily surround the egg, it can't reliably penetrate all the way through the egg white and into the center of the yolk quickly enough to make the entire egg acidic. That means parts of the egg can remain in the danger zone for botulism growth, even though the outside of the egg is sitting in an acidic brine.

Because of this, there are no approved recipes for shelf-stable home-canned pickled eggs.

Why Acidity Alone Isn't Enough

One of the biggest misconceptions in home canning is that adding vinegar automatically makes a food safe.

In reality, safe canning depends on several factors working together, including:

• The acidity of the food
• The density of the food
• How quickly heat can penetrate the jar
• The tested processing time for that specific recipe

That's why you can't simply add vinegar to any food and assume it's safe for pantry storage.

The Safe Way to Enjoy Pickled Eggs

The good news is you can absolutely make delicious pickled eggs at home.

The difference is that they should be refrigerated, not stored on the pantry shelf.

Once the eggs have been pickled, keep them in the refrigerator and follow safe refrigeration guidelines. The cold temperature helps prevent the growth of harmful bacteria while allowing the vinegar and seasonings to continue flavoring the eggs.

The Bottom Line

Pickled eggs are a perfect example of why understanding the science behind canning matters. Even though vinegar is an important part of safe food preservation, it can't overcome the challenge of a food that's too dense for the acid to fully penetrate.

When it comes to pickled eggs, enjoy them straight from the refrigerator, not from a shelf-stable canning jar. Check out this post for approved methods for preserving eggs.

4. Reusing Standard Metal Canning Lids

With the rising cost of canning supplies, it's understandable to wonder whether standard metal canning lids can be reused. After all, the lid may still look perfectly good after you've opened a jar.

However, standard metal canning lids are designed for one-time use only and shouldn't be reused for home canning.

Why Can't You Reuse Canning Lids?

If you look closely at a new canning lid, you'll notice a thin sealing compound around the underside of the rim. During the canning process, that sealing compound softens and molds itself to the rim of the jar, creating the airtight vacuum seal that keeps your food safe on the shelf.

Once the jar has been opened, that sealing compound has already been compressed. It may look unchanged, but it's no longer in its original condition.

If you reuse that same lid for another batch of canning, several things can happen:

• The jar may fail to seal during processing.
• The seal may appear successful but fail later during storage.
• Air may slowly leak into the jar, allowing spoilage or the growth of harmful organisms.

After spending months growing your food and hours preserving it, it's simply not worth risking an entire jar over a used lid.

Didn't People Used to Reuse Their Lids?

You may have heard stories of parents or grandparents reusing lids successfully. While that certainly happened, today's recommendations are based on current lid construction and food safety testing.

In fact, manufacturers have changed the sealing compound over the years. That's also why the old recommendation to simmer canning lids before using them is no longer advised for most modern lids. Today's lids are designed to be used straight from the package unless the manufacturer specifically states otherwise.

A Great Way to Reuse Old Lids

While used lids shouldn't be reused for canning, that doesn't mean they belong in the trash.

I reuse mine all the time for everyday storage around the homestead. They're perfect for:

• Dry pantry staples
• Freeze-dried foods
• Dehydrated foods
• Refrigerator leftovers
• Freezer storage
• Homemade spice blends

Since these foods aren't being preserved through the canning process, a permanent vacuum seal isn't required.

The Bottom Line

When you're preserving food for long-term pantry storage, always start with a new standard metal canning lid (use coupon code "Modern10" for 10% off at ForJars!). It's a small investment compared to the time, effort, and food you've already put into every jar.

Save your used lids for storage around the house, but rely on fresh lids whenever you're canning to help ensure a strong, reliable seal.

5. Don't Re-Can Commercially Canned Foods

Have you ever opened a large jar or can of food and wished it came in smaller portions? It's a common question, especially for home cooks who don't want to waste food.

Unfortunately, re-canning commercially canned foods at home isn't considered a safe home canning practice.

Whether it's tomato sauce, salsa, hot sauce, vegetables, or another shelf-stable product, transferring the contents into smaller jars and processing them again at home isn't recommended.

Why Isn't Re-Canning Safe?

Commercial food processors use equipment that's much different from what we have in our home kitchens. Their facilities can achieve temperatures, pressures, and processing conditions that simply aren't possible with home canning equipment.

When a product is developed for commercial canning, it's tested using those commercial methods—not home water bath or pressure canning.

That means there are no approved home canning instructions for taking a commercially canned food, opening it, and processing it again.

You Don't Know the Complete Recipe

Another challenge is that you don't know the exact formulation of the food.

Even if the ingredient list looks simple, you don't know the precise ratio of acidic and non-acidic ingredients or how the product was developed to be safely processed. Without that information, there's no way to determine a safe home canning method or processing time.

This is especially true for foods like hot sauces, pasta sauces, soups, and other prepared products that rely on proprietary recipes.

Can You Just Test the pH?

Some people wonder if they can use pH test strips to determine whether a commercial product is acidic enough to safely can at home.

Unfortunately, the answer is no.

Acidity is only one piece of safe home canning. Processing times are also based on factors like the food's density, consistency, ingredients, and how heat moves through the jar. Simply knowing the pH doesn't provide enough information to safely develop a home canning recipe.

What Should You Do Instead?

If you've opened a large commercial container and won't use it all right away, there are much safer options.

• Refrigerate leftovers and use them within the recommended time.
• Freeze extra portions in freezer-safe containers for longer storage.
• Purchase smaller containers when available if they better fit your family's needs.

The Bottom Line

Commercially canned foods are designed to be shelf stable until they're opened. Once opened, treat them like any other perishable food. Rather than trying to preserve them a second time through home canning, choose refrigeration or freezing to safely extend their usefulness.

6. Don't Rely on pH Test Strips to Determine Canning Safety

By now, you may be wondering, "If acidity is so important, can't I just use a pH test strip to determine whether my recipe is safe to can?"

It's a logical question, but the answer is no.

While pH plays an important role in home canning safety, it's only one piece of the puzzle. A pH test strip can't tell you whether a recipe is safe to preserve on your pantry shelf.

Why pH Isn't the Whole Story

For a food to be safely canned, several factors have to work together.

Researchers don't just measure the acidity of a recipe. They also study:

• How dense the food is
• How quickly heat penetrates the jar
• The size and shape of the food pieces
• The ingredients used
• The correct processing method
• The amount of time needed to safely process the food

All of these factors affect whether harmful microorganisms, including botulism spores, are destroyed or prevented from growing.

That's why safe canning recipes are carefully tested in a laboratory before they're ever published.

Why pH Test Strips Can Be Misleading

Even if a pH test strip indicates that a recipe falls below the recommended acidity level, that doesn't guarantee the entire jar is equally acidic.

Think about foods like whole vegetables, meats, or eggs. The liquid surrounding the food may be acidic, but that doesn't mean the acid has penetrated all the way to the center of every piece.

A pH strip also can't tell you whether the food has been processed long enough for heat to safely penetrate every part of the jar.

Safe Canning Is More Than a Number

It's tempting to think there's a simple shortcut for determining whether a recipe is safe, but there isn't.

Safe home canning relies on tested recipes that account for every variable, not just acidity.

That's why it's never a good idea to create your own canning recipe, modify ingredient ratios beyond what's allowed, or rely on pH testing alone to determine whether a recipe is shelf stable.

The Bottom Line

A pH test strip can be a useful tool in other areas of food preparation, but it should never replace a scientifically tested home canning recipe.

When it comes to preserving food safely, trust recipes that have been developed and tested by reliable sources. They've already done the research so you can preserve your harvest with confidence, knowing your food is safe for your family.

7. Never Skip the Added Acid When Canning Tomatoes

Tomatoes often surprise home canners because they're commonly thought of as a highly acidic food. While tomatoes do contain acid, they're actually considered a borderline-acid food when it comes to home canning.

That means some tomatoes naturally have enough acidity for safe water bath canning, while others may not. Because there's no way to know the exact acidity of every tomato, tested canning recipes call for adding acid to ensure the finished product is safe.

Why Tomatoes Need Added Acid

Several factors can affect the acidity of tomatoes, including:

• The variety of tomato
• Growing conditions and soil
• How ripe the tomatoes are when harvested
• Natural differences from one harvest to the next

Since acidity can vary so much, researchers developed tested recipes that include an added acid to bring every batch to a consistently safe level.

If you've ever followed a trusted tomato canning recipe, you've probably noticed it calls for one of the following:

• Bottled lemon juice
• Citric acid
• 5% acidity vinegar

Adding one of these ingredients isn't just a suggestion. It's an important step in creating a safe, shelf-stable product.

Why Bottled Lemon Juice Instead of Fresh?

This is one of the questions I hear most often.

While fresh lemons are certainly acidic, their acidity isn't consistent. It can vary depending on the variety, growing conditions, and ripeness of the fruit.

Bottled lemon juice, on the other hand, is manufactured to provide a standardized acidity level. That consistency is exactly what researchers use when developing tested canning recipes, which is why bottled lemon juice is recommended instead of fresh-squeezed juice.

What If You're Pressure Canning Tomatoes?

Many people assume that pressure canning eliminates the need for added acid.

In reality, many tested pressure-canning recipes for tomatoes still call for bottled lemon juice or citric acid.

Adding acid allows tomatoes to be processed safely in a shorter amount of time than would otherwise be required. That's why you'll continue to see added acid listed in many tested pressure-canning recipes.

The safest approach is simple: follow the recipe exactly as it's written, regardless of whether you're using a water bath canner or a pressure canner.

The Bottom Line

When you're canning tomatoes, don't skip the acidification step.

Whether you're making crushed tomatoes, whole tomatoes, tomato sauce, or another approved tomato recipe, adding the recommended amount of bottled lemon juice, citric acid, or other specified acid is an important part of safe home canning. Following tested recipes ensures your tomatoes are both delicious and safe to enjoy all year long.

8. Don't Can Untested Diced Tomato Recipes

If you've ever walked down the grocery store aisle, you've probably seen shelves full of canned diced tomatoes. That leads many home canners to ask, "If the store can do it, why can't I?"

It's a fair question, but commercial food processors and home canners don't use the same equipment or testing methods. While commercially canned diced tomatoes are produced using specialized equipment and proprietary processing methods, there are currently no approved home canning recipes for plain diced tomatoes from trusted home food preservation sources.

Why Aren't Plain Diced Tomatoes Recommended?

When researchers develop a home canning recipe, they don't just consider the ingredients. They also study how the food behaves during processing.

With diced tomatoes, factors like the size of the pieces, how tightly they're packed into the jar, and how heat moves through the mixture all affect whether the center of the jar reaches a safe temperature.

Since there isn't enough research to establish a safe home canning process for plain diced tomatoes, no tested recipe has been approved.

Be Careful About Adding Extra Ingredients

Another common mistake is creating homemade versions of products like canned tomatoes with peppers or "Rotel-style" tomatoes.

While it may seem like a small change, adding ingredients such as peppers, onions, garlic, or other vegetables changes the overall acidity and density of the recipe. Even small adjustments can affect how safely the food processes inside the jar.

That's why it's never a good idea to create your own canning recipe by combining ingredients or altering tested recipes beyond the recommended substitutions.

Safe Alternatives

The good news is you still have plenty of options for preserving your tomato harvest.

Instead of canning plain diced tomatoes, choose one of the many tested tomato recipes available, such as:

• Whole or halved tomatoes
• Crushed tomatoes
• Tomato sauce
• Tomato juice
• Salsa made from a tested recipe
• Stewed tomatoes using an approved recipe

These recipes have been carefully tested to ensure they're safe for home canning while still giving you plenty of versatility in the kitchen.

The Bottom Line

Just because a food is commercially canned doesn't automatically mean there's an approved way to can it at home.

When it comes to diced tomatoes, stick with tested tomato recipes that have established processing times and acidification guidelines. It's the safest way to enjoy your homegrown tomatoes throughout the year.

9. Don't Make Untested Sweetener Substitutions

As more people look for ways to reduce sugar, one of the questions I hear most often is whether it's safe to substitute sweeteners in home canning recipes.

The answer is: it depends on the recipe and the sweetener.

While sugar often adds sweetness and helps preserve color and texture, it isn't always responsible for making a recipe safe. However, that doesn't mean every sugar substitute can be swapped into a tested canning recipe.

When Can Sugar Be Reduced?

For many fruit canning recipes, sugar is included primarily for flavor rather than food safety. That means you can often reduce or even omit the sugar without affecting the safety of the finished product.

Always check the recipe notes before making changes, as tested recipes will indicate whether reducing the sugar is an approved modification.

Some Recipes Require the Full Amount of Sugar

There are exceptions.

Certain recipes rely on a specific ratio of ingredients to produce a safe, shelf-stable product. Elderberry syrup is one example where tested home canning recipes specify that the amount of sugar should not be changed.

That's why it's important to follow each recipe individually instead of assuming the same substitutions apply across every canning recipe.

What About Alternative Sweeteners?

Not all sugar substitutes have been tested for home canning.

At this time:

• Stevia has been shown to be an acceptable substitute in certain tested canning recipes because it doesn't significantly affect acidity.
• Honey can often replace a portion of the sugar when the recipe specifically allows for it, or when using a tested recipe developed for honey.
• Monk fruit, erythritol, and other sugar alcohols have not been adequately tested for home canning safety. Because there isn't enough research to know how they affect the finished product, they aren't recommended as substitutes in tested canning recipes.

When in Doubt, Follow the Tested Recipe

It's tempting to experiment with healthier sweetener options, but home canning isn't the place to guess.

If a recipe hasn't been tested using a particular sweetener, there's no way to know whether the substitution will affect the acidity, texture, processing time, or overall safety of the finished product.

The Bottom Line

When making substitutions in home canning recipes, follow the guidance provided with the tested recipe.

If the recipe says the sugar can be reduced or replaced, you can confidently make that adjustment. If it doesn't, it's best to stick with the original recipe or find one that has been specifically tested using the sweetener you'd like to use. Here are all of my low-sugar jam recipes.

10. Only Use Tested and Approved Home Canning Recipes

If there's one lesson I hope you take away from this article, it's this:

Always use tested and approved home canning recipes.

Many unsafe canning practices don't start with bad intentions. They're often family recipes that have been passed down for generations or methods that have become popular on social media. Unfortunately, just because a recipe has "always been done that way" doesn't mean it's safe by today's food preservation standards.

Home canning recommendations continue to evolve as researchers learn more about food safety, processing methods, and the science behind preserving food.

Why Older Recipes May No Longer Be Safe

One example is vinegar.

Years ago, many pickling recipes were developed using vinegar that commonly had a higher acidity level than what's typically found in grocery stores today. Modern canning recipes are based on 5% acidity vinegar, which has become the standard for home food preservation.

If you follow an older recipe without verifying the vinegar strength or comparing it to a current tested recipe, you may not be using enough acid to safely preserve the food.

Likewise, if you accidentally purchase vinegar that's labeled below 5% acidity, it shouldn't be used for home canning.

Always check the label before making pickles, relishes, salsa, or other acidified foods.

Be Careful with Online Recipes

The internet has made it easier than ever to learn new skills, but it has also made it easier for unsafe information to spread.

Before trying a new canning recipe, ask yourself:

• Has this recipe been tested for home canning?
• Does it include a recommended processing time?
• Does it specify the correct canning method?
• Does it come from a trusted source?

If you can't answer "yes" to those questions, it's best to skip the recipe.

Where to Find Trusted Canning Recipes

When you're looking for reliable home canning information, choose recipes that have been developed and tested by trusted organizations and experienced educators.

Some of my favorite resources include:

• National Center for Home Food Preservation (NCHFP)
• USDA Complete Guide to Home Canning
• Ball® Home Canning Guides and Books
• Your state's Cooperative Extension food preservation program (this is a great place to get the dial gauges on your pressure canner tested each year).
• University Extension food preservation programs
• My tested canning recipes here on my website

Using tested recipes doesn't take the creativity out of canning. It simply gives you the confidence that the food you've worked so hard to grow and preserve will be safe for your family to enjoy.

Home canning is one of the most rewarding skills you can learn, but it's also one that deserves respect. Safe food preservation isn't based on luck, tradition, or whether a jar seals. It's based on research, testing, and following methods that have been proven to work.

When in doubt, don't guess.

Choose a tested recipe, follow it carefully, and enjoy the peace of mind that comes from knowing your pantry is filled with food that's both delicious and safe.

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