How Long Are Homemade Canned Tomatoes Good For?
Properly canned homemade tomatoes are generally safe to consume for one year. For optimal quality (flavor and texture), it is best to use them within 18 months, although they can remain safe for up to two years with proper storage.
The Enduring Appeal of Home Canned Tomatoes
For generations, home canning has been a cherished tradition, allowing families to preserve the bounty of their gardens and enjoy fresh, flavorful produce year-round. Tomatoes, with their vibrant color and versatility, are a particularly popular choice for canning. The taste of homemade canned tomatoes far surpasses most store-bought varieties, offering a depth of flavor that evokes memories of summer harvests.
Health Benefits of Home Canned Tomatoes
Beyond the superior taste, home canned tomatoes offer several health benefits.
- Rich in Nutrients: Tomatoes are packed with vitamins A and C, potassium, and lycopene, a powerful antioxidant.
- Control Over Ingredients: Home canning allows you to control the ingredients, avoiding added salt, sugar, and preservatives often found in commercially canned products.
- Economic Advantage: Depending on your garden yield and tomato cost, home canning can be a cost-effective way to enjoy tomatoes throughout the year.
The Canning Process: A Brief Overview
Successful home canning requires careful attention to detail. The process involves several key steps:
- Selecting High-Quality Tomatoes: Choose ripe, unblemished tomatoes. Roma or San Marzano varieties are excellent choices for canning due to their meaty texture and low water content.
- Preparing Jars and Lids: Jars and lids must be sterilized to eliminate bacteria. This can be done by boiling them in water for 10 minutes.
- Acidifying Tomatoes: Tomatoes are a borderline acidic food and must be properly acidified to prevent the growth of Clostridium botulinum, the bacteria that causes botulism. This is done by adding lemon juice or citric acid to each jar.
- Processing in a Water Bath or Pressure Canner: Jars are submerged in boiling water (water bath canning) or processed under pressure (pressure canning) for a specific time based on the jar size and the acidity of the tomatoes. Follow a tested canning recipe.
Common Mistakes That Can Compromise Safety
Unfortunately, mistakes in the canning process can lead to spoilage and, in severe cases, botulism poisoning. Be aware of these common errors:
- Insufficient Acidification: Failing to add enough lemon juice or citric acid.
- Inadequate Processing Time: Not processing the jars for the recommended time, allowing bacteria to survive.
- Improper Jar Sealing: A weak or incomplete seal allows air and bacteria to enter the jar.
- Using Damaged Jars or Lids: Cracks or dents in jars can compromise the seal.
- Using an Unsafe Recipe: Always use tested canning recipes from reliable sources, such as the USDA Complete Guide to Home Canning or university extension services.
Understanding “Best Before” vs. “Use By” Dates
It’s crucial to differentiate between “best before” and “use by” dates. Home canned tomatoes, when properly processed and stored, don’t typically become unsafe immediately after the 12-18 month mark. Instead, their quality, in terms of flavor and texture, degrades over time. “Use by” dates, more common on perishable foods, indicate when a product should no longer be consumed.
Proper Storage for Longevity
The way you store your home canned tomatoes plays a significant role in their shelf life. Keep these guidelines in mind:
- Cool, Dark, and Dry Place: Store jars in a cool (50-70°F), dark, and dry environment. Excessive heat and light can accelerate spoilage.
- Avoid Dampness: Damp environments can promote rust on lids and potentially compromise the seal.
- Monitor for Seal Integrity: Regularly check your jars for any signs of bulging, leakage, or a broken seal. Discard any jars that show signs of spoilage.
Recognizing Signs of Spoilage
Even with the best canning practices, spoilage can still occur. Be vigilant and watch for these warning signs:
- Bulging Lid: A bulging lid indicates pressure buildup inside the jar, often due to spoilage.
- Leakage: Any leakage from the jar signals a compromised seal.
- Unusual Odor: A sour, fermented, or otherwise off-putting smell when opening the jar.
- Mold Growth: Visible mold growth inside the jar.
- Discolored or Cloudy Liquid: Changes in the liquid’s appearance can indicate spoilage.
- Forceful Release of Air When Opened: More than just a normal “pop” sound.
If you observe any of these signs, do not taste the tomatoes. Discard the entire jar immediately and safely (see below).
Safe Disposal of Spoiled Canned Tomatoes
Never taste suspect canned tomatoes. To dispose of spoiled jars safely:
- Do not empty the contents down the drain. This can spread bacteria.
- Wear gloves to prevent skin contact.
- Carefully place the jar in a sturdy plastic bag and seal it tightly.
- Dispose of the bag in a closed trash can that is inaccessible to pets and children.
- Thoroughly clean and sanitize any surfaces that may have come into contact with the spoiled contents. Boil any utensils used in the disposal.
Table: Optimal Shelf Life vs. Maximum Safe Shelf Life
| Factor | Optimal Shelf Life (Flavor & Texture Best) | Maximum Safe Shelf Life |
|---|---|---|
| Properly Canned | 12-18 Months | 2 Years |
| Storage | Cool, Dark, Dry | Cool, Dark, Dry |
| Acidification | Adequate | Adequate |
| Processing | Correct Time & Method | Correct Time & Method |
Frequently Asked Questions (FAQs)
Can I still eat home canned tomatoes if they are slightly past the 18-month mark?
Generally, yes, if they have been stored properly and show no signs of spoilage. The flavor and texture may have declined, but they should still be safe to eat. However, always err on the side of caution and discard them if you have any doubts.
How can I tell if my jars are properly sealed?
After processing, the lid should be concave, and you should not be able to press down on the center of the lid. If the lid flexes or pops when pressed, the jar is not properly sealed. A common method to test the seal is the “ping test” after cooling: a properly sealed jar will make a “ping” sound as the lid seals.
What is the best way to store home canned tomatoes?
Store home canned tomatoes in a cool (50-70°F), dark, and dry place. Basements, pantries, or cool cupboards are ideal. Avoid direct sunlight and temperature fluctuations.
Can I use store-bought diced tomatoes for canning?
While you can use store-bought diced tomatoes, it’s essential to ensure they are safe for canning. Check the ingredients to ensure they don’t contain added thickeners or other ingredients that could interfere with the canning process. Adding citric acid or bottled lemon juice is still essential to achieve the appropriate pH. Use a tested recipe using the equivalent of the store-bought product.
What happens if I don’t add enough acid to my tomatoes before canning?
Insufficient acidification can lead to botulism, a potentially fatal form of food poisoning. Clostridium botulinum thrives in low-acid environments, and proper acidification is crucial to prevent its growth.
Can I re-process jars that didn’t seal properly?
Yes, within 24 hours of the initial processing. Remove the lid, check the jar rim for any nicks or chips, replace the lid with a new, properly prepared one, and re-process the jar according to the recipe instructions. If after reprocessing the jar does not seal, refrigerate the contents and use it within a week.
Is it safe to use old canning lids?
It’s not recommended to reuse the flat lids from mason jars, as the sealing compound may not be effective after previous use. However, the metal screw bands can be reused if they are in good condition. Always use new lids for each canning batch.
Can I use a slow cooker or oven to can tomatoes?
No. These methods do not achieve the consistent, high temperatures required for safe canning and can lead to spoilage and botulism. Always use a water bath canner or pressure canner following tested recipes.
My canned tomatoes have separated – is this safe?
Separation of the tomatoes and liquid is normal and does not indicate spoilage. This is especially common when using certain tomato varieties. Simply shake the jar before opening to re-mix the contents.
How much lemon juice or citric acid should I add to each jar of tomatoes?
According to the USDA Complete Guide to Home Canning, you should add either 2 tablespoons of bottled lemon juice or 1/2 teaspoon of citric acid per quart jar of tomatoes. For pint jars, use half those amounts.
I found a very old jar of canned tomatoes in my basement. Should I risk eating them?
If the jar is several years old or shows any signs of spoilage (bulging lid, leakage, unusual odor, etc.), it’s best to discard them without tasting. The risk of botulism is not worth the potential disappointment (or illness).
Can I freeze my home canned tomatoes if I don’t use them within a year?
Yes, you can freeze home-canned tomatoes. However, freezing will significantly alter their texture. They will be best suited for sauces, soups, and stews where a soft texture is acceptable. Place the contents in a freezer-safe container, leaving headspace for expansion.
By following these guidelines, you can enjoy the delicious flavor and health benefits of home canned tomatoes safely for years to come.