1 Sterilize your gear Place lids in a small pot and cover with hot, but not boiling, water. Place freshly washed and rinsed jars in a boiling-water canner filled with hot water (Photo A). Simmer for at least 10 minutes. Then, if necessary, keep the jars warm in the water while you finish preparing the recipe. Using a jar lifter, remove jars to a clean kitchen towel.
2 Prep the canner Fill your canner half-full with fresh water and bring to a boil. Have more hot water in a teakettle or pan in case you need to top off the pot after adding the filled jars.
3 Fill with food Working with one jar at a time, funnel food into hot jars (Photo B). Leave the exact amount of headspace (empty space at the top of the jar) called for in the recipe. Measure from the top of the rim to the top of the food (Photo C). Gently work a sterilized nonmetal tool, such as a ruler-spatula or plastic chopstick, down the jar sides to release air bubbles. If necessary, add a smidge more of the food to the jars to maintain required headspace.
4 Top the jars Wipe jar rim with a clean, damp towel. Then use the magnetic wand to transfer a lid to the jar (Photo D). Screw on a band until just fingertip tight (Photo E). Screwing bands too tightly prevents a proper seal.
5 Load the canner As each jar is filled and topped, transfer it with a jar lifter to the water-filled canner and replace the pot lid (Photo F). When the canner is full, you may need to add hot water from the teakettle or pan to cover jars by 1 inch.
6 Process the jars Bring covered canner to a rolling boil. Begin timing according to recipe. Adjust heat to maintain a gentle boil. If jars clink, reduce heat. If water stops boiling, pause the timer until water returns to a boil.
7 Remove jars Use jar lifter to transfer jars to a wire rack. Leave an inch between jars. Cool 12 to 24 hours. You may hear lids pop, but test the cooled seal by pressing lightly on the center of the lid (Photo G). It should be firm and concave. If it yields to gentle pressure, the jar didn’t seal properly, so store it in the fridge and eat the food within a week.
Canning kettle Also known as boiling-water canners, these large pots have a rack inside that allows water to circulate around the jars.
Jars Use only jars made for canning, which come with lids and bands. You can reuse the jars and bands, but always buy new lids. Use the jar size specified in the recipe to ensure proper processing times.
Wide-mouth funnel Jar funnels make for clean, easy filling. They come in sizes for regular and wide-mouth jars.
Jar lifter This clamplike tool safely lifts hot jars out of boiling water.
Magnetic wand This nifty stick cleanly removes lids from hot water to place them on jars.
Ruler-spatula Release air bubbles then measure headspace with this flexible stick. (A chopstick and a ruler work, too.)
Kitchen towels Have a stack ready for wiping rims and cushioning jars.
In the thick
Pectin Some fruits, such as apples, contain enough pectin to thicken jams and jellies on their own, but most fruits need help. Be sure to use the kind of pectin (powdered, liquid or instant) called for in the recipe.
Sure-Gel This thickening agent is less common than pectin but is available online. It’s used in pie fillings and creamy-textured spreads, such as the Glass Rooster’s Hot Pepper Mustard Butter.
How does canning work?
Boiling-water canning is the most common method. The process kills harmful microorganisms, inactivates enzymes that could affect food’s flavor or color, and vacuum-seals jars to keep contaminants out. Unlike pressure canning, the boiling-water method only works with high-acid recipes, so choose recipes from respected sources (like us) who test the pH to ensure the food is safe for canning.
For the Mexican Corn Salsa pictured above and other canning recipes, click here .