Forgot Lemon Juice in Canned Tomatoes? Here’s How to Fix It

If you forgot to add lemon juice to canned tomatoes, simply stir in the juice now for acidity, which helps preserve flavor and safety in canning.

Realizing you forgot lemon juice in canned tomatoes can be stressful. The good news? You have options to correct this safety issue if you act quickly. Here’s exactly what to do based on food safety research and expert recommendations.

Why Lemon Juice Matters in Tomato Canning

Tomatoes hover near the pH 4.6 safety threshold for water bath canning. The USDA requires acidification because:

• Modern tomato varieties tend to be less acidic
• Overripe tomatoes have higher pH levels
• Added ingredients can affect acidity

Lemon juice (or citric acid) ensures safe pH levels below 4.6 to prevent botulism risk. According to the National Center for Home Food Preservation, proper acidification is non-negotiable for safe home canning.

Immediate Fixes (Within 24 Hours)

Option 1: Add Lemon Juice Directly

If jars sealed within the last day:

1. Open jars carefully
2. Add 1 tbsp bottled lemon juice per pint (2 tbsp per quart)
3. Use new lids (reuse rings)
4. Reprocess in water bath for original time

This method is approved by University of New Hampshire Extension food safety experts.

Option 2: Full Reprocessing

For maximum safety:

1. Empty jars into saucepan
2. Add required lemon juice
3. Bring to boil for 2 minutes
4. Rejar with new lids
5. Process full time

After 24 Hours: Safety First

If more than 24 hours have passed:

• Do not reprocess – potential bacterial growth makes this unsafe
• Options:
  • Freeze immediately (use within 6 months)
  • Refrigerate and use within 3 days
  • When in doubt, discard

Preventing Future Mistakes

Create a Canning Checklist

Include:

Step	Check
Acidification	□ Lemon juice added
Headspace	□ 1/2″ verified
Processing Time	□ Timer set

Alternative Acid Sources

If you dislike bottled lemon juice:

• Citric acid: 1/2 tsp per quart (equivalent to 2 tbsp lemon juice)
• Vinegar: 4 tbsp per quart (may affect flavor)

For best results, use a quality lemon juice product designed for canning.

When Lemon Juice Isn’t Needed

Exceptions where added acid isn’t required:

• Pressure canned tomatoes (240°F kills botulism spores)
• Properly fermented tomato products
• Freezer tomato preparations

Always use tested recipes from reliable sources like the National Center for Home Food Preservation.

Signs of Spoilage to Watch For

If you choose to keep unacidified tomatoes, watch for:

• Bulging lids
• Cloudy liquid
• Bubbles rising
• Unusual odors
• Mold growth

When any doubt exists, remember: “When in doubt, throw it out.” No home-canned food is worth risking botulism.