I added about 15 pounds of black raspberries to 5 gallons of blueberry honey mead (15 pounds of honey, water to 5 gallons, champaign yeast, Fermaid K). Absent mindedly, I let these sit tooooo long and extracted too much tannin from the seeds, or so that is how it taste. Tried a test glass sweetening with honey, did not hide the flavor. Any ideas on how to fix?