I can still remember how tasty Grandma Buck's raspberry jam was when I was a kid growing up. This isn't her recipe as I never learned from her how she made her jam but this one is just as tasty and my kids really love having some homemade jam in the cupboard
Add the berries to a very large pot - when the berries are at a full roiling boil they will double in size be sure you pot is large enough to accomodate. Boil for 2 minutes
Add sugar and stir well. Bring to a boil again and stirring constantly for another 2 minutes.
Remove from heat and beat with an electric mixer for 4 minutes.
Fill your water bath canner half full with water, place the lid on it and heat until it's simmering. Keep your canning rack on the counter until you're read to use it
Wash your jars, lids, and bands with hot soapy water, rinse well and keep the jars warm until you're ready to fill them to minimize the risk of a jar breaking when you're adding hot jam
Ladle hot jam into the warm jars one at a time and leave about 1/4-inch room at the top. Wipe and jam from around the rims, place lids, and bands on jar and screw on until finger tight
Place all your filled jars on the canning rack and place inside the canner making sure they're covered by about 1-2 inches of water. Place the lid on the canner and bring the water to a steady boil. Process the jars in the boiling water for about 10 minutes. Remove the lid from the canner, turn off the heat and let the jars sit for about 5 minutes.
Remove all the jars from the canner and place on a clean cloth on the count to let cool. After about 12-24 hours gently press on the center of the cooled lid to make sure it will not flex up or down. If the lid is sealed it will not move - if it does move then either refrigerate the jam or re-process it. Sealed jars can be stored up to 1 year