Fill a hot water canner about 2/3 rds full with water and bring it to a boil.

Run raspberries through a food mill to remove most of the seeds. Discard seeds.

Add crushed raspberries and blueberries in a large saucepan and stir. 

Bring the mixture slowly to a boil over medium-high heat. Stir in pectin and bring to a boil for 1 minute. Start to stir in sugar. Continue stirring until the sugar dissolves. Now, bring the mixture to a boil that cannot be stirred down. 

Boil for 1 minute, making sure to stir the jam mixture consistently to prevent it sticking to the saucepan.

Remove from heat and skim off any foam.

Test to see if it has “set” by spooning a bit onto a cold plate.  If it has formed a bit of a skin and started to give a bit like goopy Jell-O, you’re good to go, if not, cook for a bit longer.

When the jam is ready, ladle immediately into prepared jars, filling to within 1/4 inch of tops. Remove any air bubbles. 

Adding  Raspberry Blueberry Jam in The Jar

Wipe the jar rims and threads clean if needed. If using traditional canning jars, cover with 2-piece lids. Screw bands on.

If using Weck jars, carefully place the Weck rubber gasket on the lid of the jars. Place the lid on the jar and secure the lid with 2 evenly spaced Weck clamps. 

Place jars on an elevated rack in a hot water bath canner. Lower rack into canner. {Water must cover jars by  2 inches. Add boiling water, if necessary.}

Cover; bring water to a boil. Process 10 min. Remove jars and place upright on a towel to cool completely. Cool jars for 12-24 hours. 

After the jars have cooled, check the seals by pressing the middle of the lids with your finger. If lids spring back, lids are not sealed and refrigeration is necessary. {Traditional canning jars}. 

For Weck jars, check to make sure your seal is pointing downwards. 

Remove rings or clamps and store jars in a cool dark place. 

Yields about {7} 1/2 pints or {7} #902 Weck jars & {4} #788 jars