A successful tomato-canning day begins before harvest. Choose the exact tested recipe first, then gather the tomato quantity, acidifying ingredient, jars, equipment, and elevation information that recipe requires.
Choose the Recipe Before the Variety
Use a current USDA, NCHFP, or university Cooperative Extension process. The NCHFP tomato-canning introduction explains acidification and links to tested processes for whole, crushed, juiced, and sauced tomatoes.
Paste tomatoes can reduce cooking time for sauce because they often contain more solids, while slicers and cherry tomatoes can also be used in an appropriate tested process. Variety does not determine whether acidification or processing can be skipped.
Gather the Required Acid
Current NCHFP tomato directions call for acidification of whole, crushed, and juiced tomatoes. Obtain bottled lemon juice or citric acid and follow the amount specified for the jar size in the source. Do not substitute fresh lemon juice based on taste or assumed acidity.
Check Equipment
- Standard canning jars in recipe-approved sizes
- New lids or closures prepared according to manufacturer directions
- A canner suitable for the selected tested process
- Jar lifter, funnel, headspace tool, timer, and clean towels
- A reliable way to determine elevation
Inspect jars for chips and cracks and canner components for wear. Pressure canners require gauge and equipment maintenance according to the manufacturer and local Extension guidance.
Plan for Elevation and Batch Size
Use the exact altitude table attached to the selected recipe. Do not reduce processing because a jar is smaller than expected or because a batch contains fewer jars. Use only jar sizes included in the process.
Keep Tomato Mixtures Recipe-Specific
Extra onion, pepper, garlic, herbs, or oil can change a mixture. For salsa or tomato-vegetable products, follow a tested formula without increasing low-acid ingredients. Refrigerate or freeze custom recipes using suitable storage guidance instead of inventing a shelf-stable process.
Grow Tomatoes for Your Plan
Compare fruit type, maturity, and intended use in our tomato seed collection. Coordinate sowing dates and varieties if you want enough ripe fruit for a tested batch.
Frequently Asked Questions
Are naturally acidic-tasting tomatoes safe to can without added acid?
Do not judge canning requirements by taste. Follow the tested recipe’s acidification directions for the product and jar size.
Can I use fresh lemon juice?
Use the acidifying ingredient specified by the tested source. NCHFP tomato directions specify bottled lemon juice or citric acid and also describe a 5%-acidity vinegar option.
Can I add extra vegetables to tomato sauce?
Not in a shelf-stable process unless the tested formula permits them. Extra low-acid ingredients can change the required process.