Large canning pot (large enough to completely submerge the jars in water), Canning tongs, Eight 8-ounce mason jars with lids and screw-on rings, Wide-mouth canning funnel, Canning rack to go inside the pot
Place the mason jars in a large hot water bath canner (or pot). Cover with water and bring to a simmer. Simmer the center lids in separate saucepan full of water.
Place the mashed strawberries and lemon juice in a separate pot. Stir in the pectin until dissolved. Bring the strawberries to a strong boil.
Add the sugar (measure beforehand so you can add it all at once), and then return the mixture to a full (violent) boil that can't be stirred down. Boil hard for 1 minute 15 seconds. Skim foam off the top.
Remove one jar at a time from the simmering water. Pour water back into the pot. Using a wide-mouth funnel, fill each jar with jam, being careful to keep the liquid/fruit ratio consistent. Fill the jars so that they have 1/4-inch of space at the top. Run a knife down the side of the jar to get rid of air bubbles. Wipe the rim of the jar with a wet cloth to remove any residue or stickiness.
Remove the center lid from the simmering water and position it on top. Put screw bands on jars, but do not over tighten! Repeat with all the jars, and then place the jars on a canning rack and lower into the water. Place the lid on the canner, and then bring the water to a full boil. Boil hard for 10 to 12 minutes.
Turn off the heat and allow the jars to remain in the hot water for an addition 5 minutes. Remove the jars from the water using a jar lifter, and allow them to sit undisturbed for 24 hours.
After 24 hours, remove the screw bands and check the seal of the jars. The center lids should have no give whatsoever. If any seals are compromised, store those jars in the fridge. Otherwise, fill your pantry with your newly canned goodness.
Properly handled sterilized equipment will keep canned foods in good condition for one year. Making sure hands, equipment and surfaces in your canning area are clean is the first step in canning. Tips: Jars should be made from glass and free of any chips or cracks. Preserving or canning jars are topped with glass, plastic or metal lids that have a rubberlike seal. Two-piece metal lids are most common. To prepare jars before filling: Wash jars with hot, soapy water, rinse them well and arrange them open-side up, without touching, on a tray. To sterilize jars, boil them in a large saucepan, covered with water, for 10 minutes. Jars have to be sterilized only if the food to be preserved will be processed for less than 10 minutes in a boiling-water bath or pressure canner. To sterilize jars, boil them in a large saucepan, covered with water, for 10 minutes. Follow manufacturer's instructions for cleaning and preparing lids and bands. Use tongs or jar lifters to remove hot sterilized jars from the boiling water. Be sure the tongs are sterilized too: Dip the tong ends in boiling water for a few minutes before using them. All items used in the process of making jams, jellies, preserves and pickles must be clean, including any towels and especially your hands. After the jars are prepared, you can preserve the food. It is important to follow any canning and processing instructions included in the recipe and refer to USDA guidelines about the sterilization of canned products. Find Information information on canning can be found at the National Center for Home Food Preservation website: http://nchfp.uga.edu/.