Hi there !
I used Bread Yeast for the 2nd time for brewing , but the Beer had a Vinegar smell at the end .
The Yeast is in a 500 Gramm Pack and after each use I keep it tightly closed in a Freezer Bag and put it in Refrigerator .
As I had sanitized everything carefully with Iodophor , is it possible that the Yeast carried the Bacteria to the Beer ?!