Whereas wine may likely only last a couple of days, whiskey won’t react dramatically when it comes into contact with oxygen. That means when you pour from the bottle into the decanter, you still have plenty of time to properly enjoy the drink. In a decanter, just like in an opened bottle, the whiskey can last years without significantly changing the taste — provided there is an airtight seal. Without an airtight seal, a whiskey’s flavor may turn in a few months.