Add elderberries, water, and other desired optional ingredients to the pressure cooker pot and stir. Secure the lid and turn pressure release knob to a sealed position. Cook at high pressure for 10 minutes.
Set a fine mesh strainer over a bowl and pour the pot’s contents into the strainer. Press on the elderberries to remove all of the juice. Discard the elderberries.
Allow the juice to cool completely then whisk in ¾ cup honey. Add more honey to taste. Store in refrigerator for up to 2 weeks in mason jars with a pourable lid.