[question] Question from Michael Owen, Australia. I recently opened a bottle of sherry which had previously been opened some three to four weeks before. On the second opening there was quite an audible sound of escaping gas which I do not believe was evident on the original opening and the sherry now has a distinctive spritz about it. Obviously some sort of secondary fermentation but ,why now and not on the original opening? Have you seen this happen with sherry? Looking forward to your reply. [/question] [answer] This is hard to answer with any real conviciton, since a number of things might have happened. Most likely, perhaps, is that the wine resumed the fermentation of some remaining residual sugar. This could have been caused by some yeast that remained in the bottle after bottling (many sherries owe their character to long periods of exposure to yeast inside oak casks), and the process might have keen kick-started by the bottle being placed in a warmer location. It’s also possible that the sherry might have commenced a bacterial process, but this is unlikely given the alcoholic strength of the wine. [/answer]
