Kegs do not necessarily go bad once they are opened, but the beer inside can become stale or spoiled over time if not properly handled. The key to keeping keg beer fresh is to minimize exposure to oxygen and maintain the proper temperature and pressure.
When a keg is opened, it is important to keep oxygen exposure to a minimum. Oxygen can cause the beer to oxidize, leading to off flavors and a loss of freshness. One way to prevent this is by using CO2 to dispense the beer. By displacing the oxygen in the keg with CO2, you create a barrier that helps to preserve the beer's quality. This is especially important for non-pasteurized draft beer, which can spoil more quickly.
In addition to using CO2, it is crucial to maintain the proper temperature and pressure for the beer. The ideal temperature for keg beer is usually between 36-40 degrees Fahrenheit (2-4 degrees Celsius). Keeping the beer cold helps to slow down the aging process and maintain its freshness. The pressure should also be adjusted according to the type of beer and the desired carbonation level. Too much pressure can cause overcarbonation and potential foaming issues, while too little pressure can result in flat beer.
It is worth noting that the shelf life of keg beer can vary depending on whether it is pasteurized or not. Non-pasteurized draft beer, also known as “craft beer,” typically has a shorter shelf life of about 45-60 days once the keg is opened. This is because non-pasteurized beer contains live yeast and other microorganisms that can continue to ferment and change the flavor profile over time.
On the other hand, pasteurized draft beer, which has been heat-treated to kill off any yeast and bacteria, can generally stay fresh for a longer period of time, usually around 90-120 days. The pasteurization process helps to stabilize the beer and extends its shelf life. However, it is still important to handle and store pasteurized beer properly to maintain its quality.
It is important to note that the freshness of keg beer can also be affected by factors such as the quality of the beer, the cleanliness of the draft system, and the handling and storage conditions. If the beer has been mishandled or exposed to unsanitary conditions, it can spoil more quickly, regardless of whether it is pasteurized or not.
When it comes to dispensing keg beer with a party pump, which uses air instead of CO2, the freshness of the beer is significantly reduced. The exposure to oxygen and the lack of pressure control can cause the beer to go flat and spoil within a relatively short period of time. Generally, keg beer dispensed with a party pump should be consumed within 8-12 hours to ensure optimal freshness.
Keg beer does not go bad once opened, but its freshness can be affected by various factors such as oxygen exposure, temperature, pressure, and the type of beer. By using CO2 to dispense the beer, maintaining the proper temperature and pressure, and handling the keg properly, you can maximize the freshness and shelf life of the beer.