Canning 101: Preserve seasonal fruits and vegetables with our step-by-step guide.

When you’ve got more perfect tomatoes or strawberries than you can eat, you can’t just let them go to waste. That’s where preserving methods, such as freezing, drying, and canning, come in. These techniques control moisture, acid, and warm temperatures so that unseen organisms can’t work their destruction. Try your hand at canning with these detailed steps and fun recipes.

Tools you’ll need

  • Glass canning jars, clean and with no nicks or cracks
  • Two-piece canning lids: new flat lids and clean screw bands
  • Large, heavy-bottomed saucepan or soup pot (or maslin pot)
  • Large canning kettle with a rack, or a large, deep pot with a rack (so jars don’t rest on bottom of pot)
  • Wide-mouthed funnel
  • Large ladle
  • Tongs or jar lifter

How to master boiling-water canning

Use these steps for preserving high-acid foods, such as most fruits, and some vegetables with added lemon juice or vinegar. Do not use with plain vegetables, fish, meat, or other low-acid foods.

  1. Wash, peel, and cut fruit according to the recipe. Immerse light-colored fruit in 1 gallon cool water mixed with 1/ 3 cup lemon juice to prevent browning. Prepare and assemble all other ingredients.
  2. Stand jars upright on a canner rack. Fill jars and pot with water to cover by 2 inches. (Leave 3 inches of airspace above water.) Cover pot and bring to a boil. Turn off heat; leave jars in pot until ready to fill. In a heatproof bowl or pan, pour boiling water over new flat lids to soften the rubber seal. Have clean screw bands at hand.
  3. Cook jelly, jam, chutney, pickles, or other high-acid mixtures according to recipe directions. For simple canned fruit, sometimes a recipe will call for blanching the food in boiling water or hot syrup. If the fruit is soft or tender (like berries), you can pack it cold into jars without blanching.
  4. Using tongs, drain and remove jars from hot water one at a time; pack food into each. Remove air by running a long, flat utensil around the inside of the jar. Leave the correct headspace (distance between mixture and lid) as directed in the recipe. If a jar ends up with too much airspace, refrigerate it and use within a week.
  5. Wipe jar rim with a clean, damp cloth. Top with a flat lid, sealing ring down, and screw on screw ring. Do not overtighten; the ring’s only job is to hold the flat lid in place to achieve a good seal. As each jar is filled and capped, place it back on the canner rack in the water.
  6. Be sure water is 2 inches above jar tops. Cover and bring to a rolling boil; then start your timer and keep it boiling for the full time the recipe suggests.
  7. Remove cover and turn off heat. Remove jars to a cloth-lined counter or cooling rack. Cool completely. As they cool, you should hear a distinct “snap” as they seal.
  8. Press on each cooled jar lid to check the seal. If the flat lid curves downward and doesn’t move when pressed, it’s good. Label jars with contents and date. Store in a cool, dark place and eat within 6 to 12 months. If you don’t get a tight seal, refrigerate and use the food within 2 weeks.

Checking jam or jelly for “set”

When making fruit preserves, the mixture is “set” when fruit and liquid are boiled just until softly gelled. It’s important not to boil a mixture past this stage because it may turn to candy. To test for set, place a plate in your freezer for 2 minutes. Remove pan from heat; drop a spoonful of hot preserve onto the chilled plate.

Return plate to freezer for 1 minute. Push the spot of preserve with a fork. If the surface wrinkles, the preserve is set and ready to pack into hot jars. If it’s still runny and won’t wrinkle, return mixture to a boil and test at 3-minute intervals, using a new chilled plate each time. (If you have a candy thermometer, heat to 212 degrees. If you’re at high altitude, it will reach that temperature more quickly than at sea level.)