You should never consider having a cash bar at your wedding reception unless absolutely necessary. Your wedding guests should not have to pay for their own drinks. If you find that you cannot afford to host an open bar reception, then choose to serve only wine and beer or a festive punch. You may offer two different punch selections, one with alcohol and one without. Whatever your decision, remember that a cash bar is tacky and really has no place at a wedding reception.
If you decide to have an open bar, you may wonder how much to purchase. As a general rule, you will need about 8 ounces of refreshments per guest per hour of the reception. If your wedding is on a hot day, you may need more soft drinks because most people tend to drink more of them when they are hot.
A very good way to cut down on expenses is to purchase the liquor yourself. First, check with the reception site for policies they may have pertaining to alcohol. Some facilities insist on providing the beverages themselves because most of the money is spent at the bar. But that is exactly the reason why you want to provide your own beverages.
When you have found a facility that allows you to purchase the drinks and alcohol, you will need to know how much to purchase. Consult your local liquor store manager for help, but generally one bottle of champagne or wine (26 ounces) will provide 6 drinks; a keg of beer is normally 15 gallons or about 520 eight ounce servings. Purchase 8 ounce cups for the keg to yield this amount. One gallon of hard liquor (bourbon, gin, rum, vodka, etc.) makes about 32 mixed drinks. For the first hour of the reception, plan on two to three mixed drinks per adult and one to two for each adult for each hour after that. Provide soft drinks per person throughout the reception for adults and children who will not be drinking alcohol.
Your wedding reception is a time for celebration as well as an opportunity for the bride and groom to show their appreciation.