As an expert sommelier and brewer, I can tell you that the freshness of beer in a kegerator can vary depending on several factors. One of the key factors is the type of beer being stored. Different beer styles have different shelf lives and can stay fresh for varying lengths of time.
Firstly, it's important to note that pasteurized beers generally have a longer shelf life compared to non-pasteurized beers. Pasteurization is a process that involves heating the beer to kill off any potential bacteria or yeast that could cause spoilage. This process extends the beer's freshness and allows it to last longer. Typically, pasteurized beers can stay fresh for around 3 to 6 months when stored in a kegerator.
On the other hand, non-pasteurized beers have a shorter shelf life. These beers are often referred to as “craft” or “artisanal” beers and are often made with natural ingredients and traditional brewing methods. While these beers can offer unique flavors and complexities, they are more susceptible to spoilage due to the presence of live yeast and bacteria. Non-pasteurized beers in a kegerator can stay fresh for up to 2 months, although it's best to consume them sooner to fully enjoy their flavors.
Another factor that can influence the freshness of beer in a kegerator is the type of pump being used. There are two common types of pumps: air pumps and CO2 pumps. Air pumps use air pressure to dispense the beer, while CO2 pumps use carbon dioxide gas. CO2 pumps are generally preferred as they help maintain the beer's carbonation and freshness for a longer period. With a CO2 pump, you can expect your beer to stay fresh for the maximum duration mentioned earlier.
Lastly, the temperature at which the kegerator is set plays a crucial role in preserving the freshness of the beer. Ideally, a kegerator should be set at a temperature between 36°F and 40°F (2°C and 4°C). This temperature range helps slow down the aging process of the beer and maintains its quality for a longer period. If the temperature is too high, the beer may spoil more quickly and lose its freshness.
In my personal experience, I have found that maintaining a kegerator at the recommended temperature and using a CO2 pump has significantly extended the freshness of the beer. I have stored both pasteurized and non-pasteurized beers in my kegerator and have noticed that the pasteurized ones tend to last closer to the 6-month mark, while the non-pasteurized ones usually stay fresh for around 2 months.
To summarize, the freshness of beer in a kegerator can vary depending on the beer style, the type of pump used, and the temperature at which it is stored. Pasteurized beers generally last between 3 and 6 months, while non-pasteurized beers have a shorter shelf life of around 2 months. Using a CO2 pump and maintaining the kegerator at the recommended temperature can help prolong the freshness of the beer.