Water bath canning, step by step

For acid foods only (pH 4.6 or lower), like jams, pickles, fruit and acidified tomatoes. Read the whole thing, plus your tested recipe, before you start.

Fill the jars

1. Put the rack in the canner and fill it about half full with clean warm water. Preheat it to 140°F for raw-packed food or 180°F for hot-packed food (NCHFP).
2. Prepare your food exactly as the recipe says.
3. Fill the jars, leaving the headspace the recipe gives, the empty space between food and lid. As a guide, NCHFP lists 1/4 inch for jams and jellies and 1/2 inch for fruits and tomatoes (NCHFP).
4. Slide a plastic spatula around the inside to release air bubbles.
5. Wipe each rim with a clean damp cloth. A speck of food can stop a seal.
6. Put on a new flat lid and screw the band on fingertip-tight. That means secure, but not as tight as you can make it (NCHFP; also check your lid maker's directions).

Process the jars

7. Lift the jars into the canner with a jar lifter, keeping them upright.
8. Add boiling water, pouring it around the jars, until the water is at least 1 inch over the tops. For processes over 30 minutes, make it 2 inches.
9. Turn the heat to high, cover the canner and bring it to a full, vigorous boil.
10. Start the timer only once it's fully boiling. Keep a gentle but complete boil for the whole time. If it stops boiling, bring it back to a full boil and start the time over from the beginning.
11. When the time is up, turn off the heat, take the lid off and wait 5 minutes before taking the jars out.
12. Lift the jars straight up, without tilting, onto a towel or rack, at least 1 inch apart and out of cold drafts (NCHFP).

Cool, check and store

13. Leave the jars alone for 12 to 24 hours. Don't tighten the bands or press the lids while they cool.
14. Check the seals. Take off the bands and press the center of each lid. If it springs back up, it isn't sealed. A sealed lid is slightly curved down in the center, and tapping it with a spoon gives a clear ringing sound (NCHFP).
15. If a jar didn't seal, put it in the fridge and eat it within several days, or reprocess it within 24 hours with a new lid (NCHFP).
16. Wash the jars, then label each with what's inside and the date.
17. Store in a clean, cool, dark, dry place, ideally 50 to 70°F. Can only what you'll use within a year (NCHFP).

Which foods can go in a water bath? See the cheat sheet

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