My neighbor and I are home winemakers. I have been making wines for about 5 years, and he is in his second year. Today he asked me what could cause wine to carbonate in the bottle. He mabe a batch of blackberry wine, raked a few times in a 5 gallon carboy, then bottled when fermentation stopped. It was bottled about 2 months ago, had great flavor then already, and seemed to have turned out perfectly. Yesterday he opened a bottle, and found that it had carboantion bubbles in it, similar to what you would find in a can og lemon-lime soda. He didn't taste it as he was concerned that it may have gone bad. Any ideas on what could have happened, and how to avoid this in the future.