It's a resource prepared by the US Dept of Agriculture and although it's a bit lengthy (40 pages), it's a great source. I highly recommend checking it out. A few highlights are below.
"Whether food should be processed in a pressure canner or boiling-water canner to control botulinum bacteria depends on the acidity of the food. Acidity may be natural, as in most fruits, or added, as in pickled food. Low-acid canned foods are not acidic enough to prevent the growth of these bacteria. Acid foods contain enough acid to block their growth, or destroy them more rapidly when heated. The term “pH” is a measure of acidity; the lower its value, the more acid the food. The acidity level in foods can be increased by adding lemon juice, citric acid, or vinegar."
"To maintain good natural color and flavor in stored canned food, you must:
• Remove oxygen from food tissues and jars,
• Quickly destroy the food enzymes,
• Obtain high jar vacuums and airtight jar seals."
"All jams, jellies, and pickled products processed less than 10 minutes should be filled into sterile empty jars. To sterilize empty jars after washing in detergent and rinsing thoroughly, submerge them, right side up, in a boiling-water canner with the rack in the bottom. Fill the canner with enough warm water so it is 1 inch above the tops of the jars. Bring the water to a boil, and boil 10 minutes at altitudes of less than 1,000 ft. At higher elevations, boil 1 additional minute for each additional 1,000 ft elevation. Reduce the heat under the canner, and keep the jars in the hot water until it is time to fill them. Remove and drain hot sterilized jars
one at a time, saving the hot water in the canner for processing filled jars. Fill the sterilized jars with food, add lids, and tighten screw bands."
"When you remove hot jars from a canner, do not retighten their jar lids. Retightening of hot lids may cut through the gasket and cause seal failures. Cool the jars at room temperature for 12 to 24 hours. Jars may be cooled on racks or towels to minimize heat damage to counters. "
"Do not store jars above 95°F or near hot pipes, a range, a furnace, under a sink, in an uninsulated attic, or in direct sunlight. Under these conditions, food will lose quality in a few weeks or months and may spoil. Dampness may corrode metal lids, break seals, and allow recontamination and spoilage."
Be careful and please take the time to follow safe canning procedures.