I believe the cider was darker too. I had two batches made in quick succession and one was significantly darker but it just chalked it up to whatever/ some unknown. My vocabulary and palette are a work in progress so I think Im gonna bring some to the local home brew store and have the owner taste it. He is a pretty helpful guy and the only person I know locally who would be able to ID the flavor for sure. Perhaps mildewy is a bad word. Maybe musty, or stale but I don't think sherry, paper or cardboard fit the bill. I may try leave a few ounces of wine or beter yet cider sit overnight to see what its like. thanks for the info. And no, the cider was not topped up or fortified with any other sugars. I did dose it with 9 Campden tabs and let is sit before starting