Prepare gauze in advance and wrap coffee beans in it. This is necessary in order to give the jam an extraordinary aroma.
Rinse the blackberries and dry. It is convenient to do this in a colander. If necessary, remove any excess. Place the sugar and coffee beans in a saucepan and heat over low heat for about 10 minutes to form a syrup.
Once it has boiled, add the blackberries and cook for 20-30 minutes. Then remove the cheesecloth containing the coffee beans. Pour the jam into clean, sterilized jars and seal. Leave in a warm place until it cools, then put in the cold.
Serve the jam in a small bowl; for more flavor, you can add a sprig of mint. You can use jam as a filling for anything.