How-to: open bar and alcohol for your wedding
Here is one last thing, which we think is the most important part about the entire "Open Bar" concept: plenty of fresh drinking water. Here is why: throughout the evening, your guests will consume a ton of alcohol. When processed by the body, alcohol requires water - hence a bad hangover you and your guests should expect to have. To avoid bad dehydration, provide plenty of drinking water, and both you and your guests will skip the headache and the pain of hangover the next day and will remember the wedding much more fondly that they would have had.
This is also one of the reasons the state laws of most, if not all, states require fresh drinking water to be available for free at any bar upon request.
So make plenty of water available throughout the evening. Place drinking water right next to the bar, always have it available, and if you have the water in big jugs, have your waiters add a bit of ice and a slice of lemon to the water - it will be much more attractive, allowing the crowd to party through the night and not wear out too quickly.
Early in the wedding reception, water bottles are the best option as people can sip water as necessary while they wait, should they choose not to drink at all or should they take a break from all the champagne they consumed at the ceremony. At the reception, serve water in jugs - you will avoid the trashing effect of a ton of empty water bottles lying around. As the guests start to take off, ensure they will a bottle of water or two with them in the cab. They will thank you for it the next morning.