Preserving Tomatoes by Canning
Preserving tomatoes relies on high acidity to keep the contents safe. By peeling, packing them into jars with added lemon juice, and processing them in a boiling water bath, you capture the summer harvest for year-round use without needing a pressure canner.
Cleanliness is the foundation of storage.
Ensure every jar is sterilized and the rims are free of chips to prevent seal failure. Work in batches to keep the tomato temperature consistent.
- large stockpot
- water bath canner with rack
- canning jars with new lids
- jar lifter
- slotted spoon
What goes in.
- 20 lbfirm, ripe tomatoes
- 7 tbspbottled lemon juice
- 2 tspcanning salt (optional)
Don't skip the lemon juice
Bottled lemon juice ensures the acidity levels remain constant across different tomato varieties, which is the singular factor that keeps your jars shelf-stable.
The method.
Blanch and peel
Cut a small X into the base of each tomato. Submerge them in boiling water for 45 seconds, then move immediately to an ice bath. The skins will slide off under light pressure.
Prepare jars
Place 1 tablespoon of bottled lemon juice into the bottom of each quart jar. Pack the raw, peeled tomatoes tightly into the jars, leaving 1/2 inch of headspace at the top.
Release bubbles
Run a non-metallic spatula or bubble wand along the inside edges of the jars to release trapped air. Adjust headspace if needed by adding more tomatoes or juice.
Process
Wipe the rims with a damp cloth, apply lids, and tighten rings until finger-tight. Lower jars into the boiling water bath, cover, and process for 85 minutes.
Cool
Remove jars with a lifter and set them on a towel-lined counter. Leave them undisturbed for 24 hours. The center of the lid should be concave and firm to the touch.
Other turns to take.
Crushed Tomatoes
Simmer the tomatoes in a pot for 5 minutes before packing into jars to fit more fruit into each container.
When it doesn't go to plan.
Discard any tomatoes with deep bruises or mold, as these carry bacteria that can ruin an entire batch.
Always use new lids for every canning session to guarantee a proper vacuum seal.
If a jar fails to seal after 24 hours, place it in the refrigerator and use it within a week.
The ones that keep coming up.
Can I use fresh lemon juice instead of bottled?
No. Bottled juice has a standardized acidity level, whereas fresh juice varies, which could lead to an unsafe environment inside the jar.
Why did my jars lose liquid during processing?
This is usually caused by fluctuating heat in the water bath or filling the jars too tightly. The tomatoes remain safe to eat as long as the seal is intact.
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