I opened one jar of the plain blueberries with syrup and tasted...did not have an intense blueberry flavor, but didn't taste terribly watered down as I feared. The canning water had been so purple that I originally feared I had a broken jar (then wished that I did!). The blueberries had lost a lot of color, but after being refrigerated overnight, the entire jar, including the blueberries had become the beautiful purple/blue color I hoped for. The taste is okay. I'll be able to use them in something. The blueberry pie filling made a delicious cobbler. The blueberry jelly, blueberry-lemon jam, and the blueberry-lemonade concentrate also turned out well. I froze a lot of berries on cookie sheets then froze in pint and quart bags. All-in-all, I'm happy with the results. Blueberries were very easy to work with, needing little preparation. I appreciate the advice from both of you. Thank you.
Source : https://www.houzz.com/discussions/4603634/how-to-salvage-canned-blueberries158