The Ultimate Guide to Canning Tomatoes Safely + 2 Garden Tomato Sauce Recipes

There’s nothing quite like the taste of tomatoes fresh from the garden, and preserving them allows you to enjoy that vibrant flavor all year long. But when it comes to canning tomatoes — especially mixed vegetable sauces — safety is key. Follow these tips and tricks to create delicious, shelf-stable tomato sauces safely.

Why Safety Matters in Tomato Canning

Tomatoes are naturally acidic, which makes them ideal for water-bath canning. However, adding other vegetables like onions, peppers, zucchini, or garlic can raise the pH, creating an environment where bacteria like Clostridium botulinumcan grow if the sauce isn’t properly processed.

To can safely, you need:

• Proper acidification with bottled lemon juice or citric acid

• Correct processing time in boiling water or a pressure canner

• Sterilized jars and lids

Water-Bath vs. Pressure Canning

• Water-Bath Canning: Perfect for high-acid foods such as plain tomato sauces, jams, or pickles. Acidification is essential when adding vegetables.

• Pressure Canning: Necessary for low-acid foods like mixed vegetable sauces, salsas, or soups. The high pressure ensures that all bacteria and spores are destroyed.

Essential Tips for Safe Canning

1. Sterilize jars and lids — rinse in boiling water or use a hot dishwasher cycle.

2. Use bottled lemon juice — its acidity is standardized; fresh lemon juice can vary.

3. Leave proper headspace — usually ½ inch (1.25 cm) for sauces.

4. Wipe jar rims clean before sealing.

5. Cool jars upright — do not flip jars with sauces; the seal forms as the jars cool.

6. Label jars with date and any special notes, like “with lemon juice.”

Common Mistakes to Avoid

• Skipping acidification in low-acid sauces

• Under-processing jars in boiling water

• Using old, dented, or damaged lids

• Storing jars at room temperature without a proper seal

Version 1: Garden Tomato Sauce with Fresh Vegetables

This sauce is a celebration of fresh vegetables, simmered for hours to concentrate their flavor. You can adjust it based on what’s in your garden, including Italian tomatoes, cherry tomatoes, extra onion and garlic, and even fresh hot peppers for a little kick.

Ingredients (makes about 6–8 pints)

• 18- 20 large Italian tomatoes, plus any extra cherry tomatoes (chopped roughly)

• 3–4 medium onions, chopped

• 1 whole garlic, cloves peeled

• 2 medium zucchinis, chopped

• 2 red bell pepper, chopped

• 3–4 fresh hot peppers (optional, adjust to taste)

• 2 tbsp. olive oil (as needed)

• 2–3 teaspoons salt (to taste)

• ½ teaspoon black pepper (adjust to taste)

• 2 tbsp. sugar

• 2-3 tbsp. dried herbs (basil, oregano, thyme)

• Bottled lemon juice: 1 Tbsp per pint or 2 Tbsp per quart jar

Instructions

1. Prepare the sauce: Heat olive oil in a large pot. Sauté onions, garlic, and hot peppers (if using) until translucent.

2. Add vegetables: Add zucchinis, bell peppers, and all tomatoes. Season with salt, pepper, sugar, and herbs.

3. Simmer: Cook for at least 2 hours, stirring occasionally, until the sauce is thick and flavorful.

4. Optional puree: Use a food processor, blender, or immersion blender to puree the sauce to your preferred consistency before canning. (This is better because the tomatoes were not peeled)

5. Sterilize jars and lids while sauce cooks.

6. Add lemon juice to jars: 1 Tbsp per pint or 2 Tbsp per quart.

7. Fill jars with hot sauce, leaving ½ inch (1.25 cm) headspace. Wipe rims clean and seal with lids and screw bands fingertip-tight.

8. Process jars in boiling water:

   • Pints: 35 minutes

   • Quarts: 40 minutes
     (Adjust for altitude if needed)

9. Cool upright on a towel or rack for 12–24 hours.

10. Check seals and label jars with date.

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Version 2: Roasted Tomato Garden Sauce

For a deeper, richer flavor, this version uses roasted tomatoes. Roasting concentrates the natural sweetness of the tomatoes and adds a caramelized depth to the sauce.

Ingredients (makes about 6–8 pints)

1 tray (about 3–4 lbs) of Italian, cherry, or mixed tomatoes (chopped roughly if large)
2 tbsp. olive oil (as needed)
2–3 teaspoons salt (to taste)
½ teaspoon black pepper (adjust to taste)
2–3 tbsp. dried herbs (basil, oregano, thyme)

For the sauce base:

• 3–4 medium onions, chopped

• 1 whole garlic, cloves peeled

• 2 medium zucchinis, chopped

• 2 red bell peppers, chopped

• 3–4 fresh hot peppers (optional, adjust to taste)

• 2 tbsp. sugar

• More olive oil as needed

For safe canning:

• Bottled lemon juice: 1 Tbsp per pint or 2 Tbsp per quart jar

Instructions

1. Roast the tomatoes: Preheat oven to 400°F (200°C). Spread tomatoes on a baking sheet, drizzle with olive oil, sprinkle with salt, pepper, and herbs. Roast for about 40 minutes, until softened and slightly caramelized.

2. Puree roasted tomatoes: Once roasted, puree them in a food processor or blender until smooth.

3. Prepare the sauce base: Heat olive oil in a large pot. Sauté onions, garlic, and hot peppers (if using) until translucent. Add zucchini and bell peppers.

4. Combine: Stir in the pureed roasted tomatoes, sugar, and adjust seasoning with more salt, pepper, or herbs as needed.

5. Simmer: Cook the sauce for 30–60 minutes, stirring occasionally, to let the flavors meld.

6. Optional puree: For a smoother sauce, puree again with an immersion blender or food processor before canning.

7. Sterilize jars and lids while sauce cooks.

8. Add lemon juice to jars: 1 Tbsp per pint or 2 Tbsp per quart.

9. Fill jars with hot sauce, leaving ½ inch (1.25 cm) headspace. Wipe rims clean and seal with lids and screw bands fingertip-tight.

10. Process jars in boiling water:

• Pints: 35 minutes

• Quarts: 40 minutes
  (Adjust for altitude if needed)

1. Cool upright on a towel or rack for 12–24 hours.

2. Check seals and label jars with date.

Canning Roasted Tomato Garden Sauce Recipe

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Author: Richelle Fortin

For a deeper, richer flavor, this version uses roasted tomatoes. Roasting concentrates the natural sweetness of the tomatoes and adds a caramelized depth to the sauce.

Ingredients

For the Roasted Tomatoes

• (makes about 6–8 pints)
• 1 tray (about 3–4 lbs) of Italian, cherry, or mixed tomatoes (chopped roughly if large)
• 2 tbsp. olive oil (as needed)
• 2–3 teaspoons salt (to taste)
• ½ teaspoon black pepper (adjust to taste)
• 2–3 tbsp. dried herbs (basil, oregano, thyme)

For the sauce base:

• 3–4 medium onions, chopped
• 1 whole garlic, cloves peeled
• 2 medium zucchinis, chopped
• 2 red bell peppers, chopped
• 3–4 fresh hot peppers (optional, adjust to taste)
• 2 tbsp. sugar
• More olive oil as needed

Instructions

1. For safe canning:
2. Bottled lemon juice: 1 Tbsp per pint or 2 Tbsp per quart jar
3. Instructions
4. Roast the tomatoes: Preheat oven to 400°F (200°C). Spread tomatoes on a baking sheet, drizzle with olive oil, sprinkle with salt, pepper, and herbs. Roast for about 40 minutes, until softened and slightly caramelized.
5. Puree roasted tomatoes: Once roasted, puree them in a food processor or blender until smooth.
6. Prepare the sauce base: Heat olive oil in a large pot. Sauté onions, garlic, and hot peppers (if using) until translucent. Add zucchini and bell peppers.
7. Combine: Stir in the pureed roasted tomatoes, sugar, and adjust seasoning with more salt, pepper, or herbs as needed.
8. Simmer: Cook the sauce for 30–60 minutes, stirring occasionally, to let the flavors meld.
9. Optional puree: For a smoother sauce, puree again with an immersion blender or food processor before canning.
10. Sterilize jars and lids while sauce cooks.
11. Add lemon juice to jars: 1 Tbsp per pint or 2 Tbsp per quart.
12. Fill jars with hot sauce, leaving ½ inch (1.25 cm) headspace. Wipe rims clean and seal with lids and screw bands fingertip-tight.
13. Process jars in boiling water:
14. Pints: 35 minutes
15. Quarts: 40 minutes
16. (Adjust for altitude if needed)
17. Cool upright on a towel or rack for 12–24 hours.
18. Check seals and label jars with date.

Did you make this recipe?

Tag @richelle.fortin on instagram and hashtag it #strawberry dessert

Canning Garden Tomato Sauce with Fresh Vegetables Recipe

Print

With ImageWithout Image

Author: Richelle Fortin

This sauce is a celebration of fresh vegetables, simmered for hours to concentrate their flavor. You can adjust it based on what’s in your garden, including Italian tomatoes, cherry tomatoes, extra onion and garlic, and even fresh hot peppers for a little kick.

Ingredients

• 18 - 20 large Italian tomatoes, plus any extra cherry tomatoes (chopped roughly)
• 3–4 medium onions, chopped
• 1 whole garlic, cloves peeled
• 2 medium zucchinis, chopped
• 2 red bell pepper, chopped
• 3–4 fresh hot peppers (optional, adjust to taste)
• 2 tbsp. olive oil (as needed)
• 2–3 teaspoons salt (to taste)
• ½ teaspoon black pepper (adjust to taste)
• 2 tbsp. sugar
• 2-3 tbsp. dried herbs (basil, oregano, thyme)
• Bottled lemon juice: 1 Tbsp per pint or 2 Tbsp per quart jar

Instructions

1. Prepare the sauce: Heat olive oil in a large pot. Sauté onions, garlic, and hot peppers (if using) until translucent.
2. Add vegetables: Add zucchinis, bell peppers, and all tomatoes. Season with salt, pepper, sugar, and herbs.
3. Simmer: Cook for at least 2 hours, stirring occasionally, until the sauce is thick and flavorful.
4. Optional puree: Use a food processor, blender, or immersion blender to puree the sauce to your preferred consistency before canning. (This is better because the tomatoes were not peeled)
5. Sterilize jars and lids while sauce cooks.
6. Add lemon juice to jars: 1 Tbsp per pint or 2 Tbsp per quart.
7. Fill jars with hot sauce, leaving ½ inch (1.25 cm) headspace. Wipe rims clean and seal with lids and screw bands fingertip-tight.
8. Process jars in boiling water:
9. Pints: 35 minutes
10. Quarts: 40 minutes
11. (Adjust for altitude if needed)
12. Cool upright on a towel or rack for 12–24 hours.
13. Check seals and label jars with date.

Did you make this recipe?

Tag @richelle.fortin on instagram and hashtag it #strawberry dessert