As an experienced sommelier and brewer, I can confidently say that using a bag to contain hops is highly recommended when adding them to your beer. This is especially true when dry hopping in the keg.
The primary reason for using a bag is to prevent any unwanted particles or debris from entering your beer. Hops can break down during the brewing process, and loose hop particles can easily find their way into your glass if not properly contained. This can result in an unpleasant drinking experience and potentially clog up your keg system.
When it comes to dry hopping in the keg, it's important to consider the extended duration that the hops are in contact with the beer. Unlike traditional hopping during the boil, dry hopping involves adding hops directly to the fermenter or keg after fermentation has completed. The hops are left to steep in the beer for an extended period, typically several days to a week, to extract their aromatic compounds.
During this time, the hops can break apart and release small particles into the beer. By using a muslin or cheesecloth bag, you can keep these particles contained and easily remove them when the desired hop flavor and aroma have been achieved. This not only helps maintain clarity in your beer but also prevents any clogging issues in your keg system.
I have personally encountered situations where hops were not properly contained, resulting in clogged keg lines. This can be a frustrating experience, as it requires disassembling and cleaning the lines to remove any hop residue. By using a bag, you can avoid this inconvenience altogether.
In addition to practical reasons, using a bag can also make it easier to control the amount of hop flavor and aroma in your beer. By containing the hops in a bag, you can easily remove them once you've achieved your desired level of hopping. This allows for more precise control over the final product and ensures consistency in your brewing process.
To summarize, using a bag to contain hops is highly recommended, especially when dry hopping in the keg. It helps prevent unwanted particles from entering your beer, avoids clogging issues in your keg system, and allows for better control over hop flavor and aroma. So, next time you're brewing, be sure to grab a muslin or cheesecloth bag to keep those hops in check!