For generations, home canning has been a cherished tradition, a way to preserve the bounty of the garden and enjoy delicious, homegrown flavors year-round. Tomatoes, with their vibrant color and versatility, are a favorite for canning enthusiasts. But in today’s world of updated food safety guidelines, a common question arises: Can you can tomatoes safely without adding lemon juice or citric acid?
The short answer is: it’s not recommended. Here’s why.
The Acidity Factor: Why It Matters in Tomato Canning
The safety of home-canned goods hinges on acidity. Foods with a pH of 4.6 or lower are considered high-acid and can be safely processed in a boiling water bath canner. This is because the high acidity prevents the growth of *Clostridium botulinum*, the bacteria that causes botulism, a potentially fatal form of food poisoning.
Tomatoes, unfortunately, fall into a gray area. While they are often considered acidic, their pH can vary depending on the variety, growing conditions, and even the ripeness of the fruit. Some tomatoes may be naturally acidic enough to can safely without added acid, but there’s no reliable way for home canners to know for sure.
The Role of Lemon Juice and Citric Acid
This is where lemon juice and citric acid come in. Adding these acids to your tomato canning recipes ensures that the pH of the final product is safely below 4.6, regardless of the natural acidity of your tomatoes.
- Lemon Juice: Bottled lemon juice is a readily available option for increasing acidity. It’s crucial to use bottled juice because its acidity level is consistent, unlike fresh lemon juice, which can vary.
- Citric Acid: Citric acid powder is another effective way to acidify tomatoes. Many canners prefer it because it doesn’t alter the flavor of the tomatoes as much as lemon juice or vinegar.
What About Pressure Canning?
You might wonder if pressure canning eliminates the need for added acid. After all, pressure canning reaches higher temperatures, which can kill *Clostridium botulinum* spores. However, even when pressure canning tomatoes, adding acid is still essential.
According to Clemson University Extension, USDA researchers based the pressure canning process for raw packed tomatoes on killing molds, yeasts, and spoilage organisms in acidified tomatoes, relying on the low pH to prevent *C. botulinum* growth. If they had developed a pressure canning process for unacidified tomatoes that targeted *C. botulinum* spores, it would have required a much longer processing time.
Why the Recommendations Changed
So, why did our grandparents can tomatoes without adding acid? There are a couple of reasons:
- Tomato Varieties: Older varieties of tomatoes tended to be more acidic than many modern varieties, which have been bred for sweetness and other traits.
- Evolving Knowledge: As our understanding of food safety has grown, so have canning recommendations. We now know that relying on the natural acidity of tomatoes alone is too risky.
The Consequences of Skipping Acid
Forgetting to add lemon juice or citric acid to your canned tomatoes can have serious consequences. Without sufficient acidity, *Clostridium botulinum* spores can germinate and produce botulinum toxin, which can cause paralysis, respiratory failure, and even death.
While it might be tempting to risk it, botulism is not something to take lightly. It’s far better to follow current recommendations and add acid to every batch of canned tomatoes.
How to Acidify Your Tomatoes
Adding acid to tomatoes is simple. Before filling your jars, add either:
- 1 tablespoon of bottled lemon juice per pint jar, or 2 tablespoons per quart jar.
- ½ teaspoon of citric acid powder per pint jar, or 1 teaspoon per quart jar.
- 4 tablespoons of 5% acidity vinegar per quart jar. Vinegar may impart an undesirable flavor.
Then, fill the jars with your prepared tomatoes, leaving the recommended headspace, and process according to a tested recipe.
What If You Forgot to Add Acid?
If you’ve already canned a batch of tomatoes without adding acid, do not eat them. Botulism is a serious risk, and it’s not worth gambling with your health.
The safest option is to discard the jars. If you’re feeling resourceful, you can freeze the tomatoes for later use, as freezing prevents the growth of *Clostridium botulinum*. Alternatively, you can reprocess them, adding the correct amount of acid this time. However, keep in mind that reprocessing can affect the texture and flavor of the tomatoes.
The Bottom Line
While it might be tempting to skip the lemon juice or citric acid when canning tomatoes, it’s not worth the risk. Adding acid is a simple and effective way to ensure that your canned tomatoes are safe to eat. So, follow the current recommendations, use a tested recipe, and enjoy the delicious taste of homegrown tomatoes with peace of mind.