Home canning tomatoes is a fantastic way to enjoy the taste of summer all year round. Imagine the satisfaction of using your own homegrown tomatoes, or those from a local farmer’s market, to create delicious sauces, salsas, and more. But before you dive in, there’s a crucial step you need to know about: adding lemon juice. You might be wondering, “Why is lemon juice so important?” Well, let’s get into the juicy details!
The Importance of Acidity in Tomato Canning
Tomatoes are naturally acidic, but here’s the catch: their acidity can vary. Over the years, different tomato varieties have been cultivated, and some of these have lower acidity levels than their predecessors. In fact, some tomatoes have been tested with pH values at or above 4.6, and some even higher. Why is this significant? Because a pH of 4.6 is the critical threshold for preventing the growth of *Clostridium botulinum*, the bacteria that causes botulism. Botulism is a severe and potentially fatal form of food poisoning, and we definitely want to avoid it.
Adding lemon juice (or citric acid) to your tomatoes ensures that the pH is low enough to prevent the growth of this nasty bacteria. It’s a simple step that gives you the confidence of knowing that the tomatoes you’ve preserved are safe for you and your family to enjoy.
How Lemon Juice Safeguards Your Canning
*Clostridium botulinum* spores cannot germinate in acidic environments. By adding the correct amount of lemon juice, you create an environment where these spores cannot grow, regardless of whether you’re using a water bath canner or a pressure canner.
The USDA considers many variables when making canning recommendations, including different canner operations, altitudes, and crop varieties. Adding acid to tomatoes provides a safeguard, ensuring safe results regardless of geography, elevation, tomato variety, or local growing conditions.
How Much Lemon Juice to Add
The acidification process is simple. Here’s a quick guide:
- For quarts: Add two tablespoons of bottled lemon juice or ½ teaspoon of citric acid per quart of tomatoes.
- For pints: Use one tablespoon of bottled lemon juice or ¼ teaspoon of citric acid.
You can add the bottled lemon juice directly to the jars before or after filling them with tomatoes. Just make sure you add the lemon juice to each jar and use the recommended amounts precisely.
Why Bottled Lemon Juice?
It’s essential to use bottled lemon juice and not freshly squeezed. Bottled lemon juice has a standardized acidity level, while fresh-squeezed juice can have varying levels, making it unreliable for canning purposes.
Can I Adjust the Taste?
If you’re concerned about the taste, don’t worry! You can add sugar to offset the acid taste after opening and processing the jars. However, it’s crucial not to reduce the amount of acid before canning. Safety first, flavor second!
Pressure Canning and Acidification
Even if you’re using a pressure canner, you still need to add lemon juice. The USDA researchers based the pressure canning process for raw packed tomatoes on killing spoilage organisms in acidified tomatoes. If a pressure canning process for unacidified tomatoes targeted *C. botulinum* spores, it would require a much longer processing time.
Step-by-Step: Adding Lemon Juice to Canned Tomatoes
Here’s how to incorporate lemon juice into your tomato canning process:
- Wash and peel your tomatoes. Blanching them makes this easier.
- Cut the peeled tomatoes in half or quarters, depending on their size. Small tomatoes can be left whole.
- Add the tomatoes directly to each jar, pressing down to fill the space with juices.
- Add the correct amount of lemon juice (or citric acid) to each jar.
- If desired, add salt to the jars for flavor.
- Pack the tomatoes into the jar, pressing down to fill the space with juice.
- Leave ½ inch of headspace (the space between the food and the lid).
- Remove any air bubbles, wipe the rim clean, and place the seal and ring.
- Place the jar in your canner and repeat with the remaining jars.
- Process according to either pressure canner or water bath canning directions.
Resources for Safe Canning
Always use current, research-based recipes when canning tomatoes or any other produce. Recommendations and preservation methods have changed, and it’s essential to use current methods to ensure a safely preserved product.
Here are some recommended resources:
- MSU Extension Michigan Fresh
- USDA Guide to Complete Home Canning
- National Center for Home Food Preservation
- So Easy to Preserve book
- A current Ball Blue Book
Beyond Safety: The Benefits of Canning Tomatoes
Year-Round Tomato Goodness
Canning allows you to enjoy the taste of fresh, seasonal tomatoes throughout the year. No more relying on bland, store-bought tomatoes in the winter!
Control Over Ingredients
When you can your own tomatoes, you have complete control over the ingredients. You can choose organic tomatoes, add your favorite herbs and spices, and avoid any unwanted additives or preservatives.
Cost-Effective
Canning your own tomatoes can save you money in the long run. Instead of buying expensive canned tomatoes from the store, you can use your own homegrown or locally sourced tomatoes and preserve them at a fraction of the cost.
Environmentally Friendly
Canning is an environmentally friendly way to preserve food. You reduce your reliance on commercially processed and packaged foods, which often have a significant carbon footprint.
Citric Acid as an Alternative
If you don’t have bottled lemon juice on hand, citric acid is an excellent alternative. It’s readily available in granular form and can be used for other cooking purposes.
Don’t Skip the Acid!
While it might be tempting to skip the lemon juice (especially if you’ve been canning tomatoes for years without it), it’s not worth the risk. Adding lemon juice is a simple, effective way to ensure that your home-canned tomatoes are safe and delicious. So, grab that bottle of lemon juice, follow the guidelines, and enjoy the satisfaction of preserving your own tomatoes with confidence.