When it comes to the shelf life of a cask of beer, there are a few factors to consider. Ideally, cask beer should be consumed within 5 – 7 days of tapping. This timeframe ensures that you are able to enjoy the beer at its freshest and fullest flavor. However, it's important to note that this is a general guideline and the actual shelf life can vary depending on a few different factors.
One factor that can affect the shelf life of a cask of beer is the style of the beer itself. Darker and/or higher ABV (alcohol by volume) beers generally have a longer shelf life compared to lighter and lower ABV beers. The flavors and complexities of these darker and stronger beers tend to hold up better over time. So, if you have a cask of a rich, dark stout or a high ABV barleywine, you can expect it to keep for a further 2 – 3 days beyond the initial 5 – 7 day window.
Another important factor that can impact the longevity of a cask of beer is the cleanliness of the cask tap. The quality of the beer can quickly deteriorate if the tap is not properly cleaned. Any residual bacteria or yeast left in the tap can contaminate the beer and cause off-flavors or spoilage. As a brewer, I cannot stress enough the importance of keeping your cask tap clean and sanitized. This ensures that the beer remains fresh and enjoyable for as long as possible.
It's worth mentioning that once a cask of beer is opened, it begins to oxidize. This means that the flavors can change and the beer can become stale over time. The rate of oxidation can vary depending on factors such as temperature, exposure to light, and the amount of headspace in the cask. To minimize oxidation, it's best to store the cask in a cool, dark place and consume it as soon as possible after tapping.
In my personal experience as a sommelier and brewer, I have found that the quality of cask beer can vary after the initial 5 – 7 day period. Some beers may still taste relatively fresh and enjoyable, while others may have noticeably deteriorated in flavor. It's always best to trust your senses and judgment when determining if a cask of beer is still good to drink.
To summarize, a cask of beer should ideally be consumed within 5 – 7 days of tapping. Darker and/or higher ABV beers may keep for an additional 2 – 3 days. However, it's important to ensure that the cask tap is clean to maintain the quality of the beer. Remember to store the cask in a cool, dark place and trust your senses when determining if the beer is still fresh and enjoyable.