As an experienced sommelier and brewer, I can understand the appeal of using a secondary fermenter for certain beers. However, it is important to note that the decision to use a secondary fermenter is not always necessary or beneficial for every batch of beer.
The primary purpose of transferring beer to a secondary fermenter is to allow the flavors and aromas to mellow over time. This can be particularly useful for beers with a higher original gravity, as the additional fermentation time can help to balance out the flavors and create a smoother finished product. By giving the beer more time to age and settle, any harsh or off flavors can also diminish, resulting in a more enjoyable drinking experience.
Another benefit of using a secondary fermenter is the potential for yeast to drop out of solution. This can help to produce a clearer beer, as the suspended yeast and other particles will have more time to settle to the bottom of the fermenter. This is especially important if you are aiming for a crystal clear final product, such as with lagers or certain light-colored ales. However, it is worth noting that for many beers with a lower original gravity (1.040 or lower), or beers that are typically served cloudy (such as certain wheat beers or hazy IPAs), the use of a secondary fermenter may not be necessary.
It's important to consider the specific characteristics and goals of your beer when deciding whether or not to use a secondary fermenter. For example, if you are brewing a hop-forward beer where freshness and vibrant hop flavors are crucial, it may be best to skip the secondary fermenter and package the beer as soon as primary fermentation is complete. This will help to preserve the delicate hop aromas and flavors that can fade over time.
Additionally, the decision to use a secondary fermenter can also depend on practical considerations. Transferring beer to a secondary vessel can introduce oxygen, which can lead to oxidation and off flavors if not done carefully. It also requires additional time, effort, and equipment for cleaning and sanitizing the secondary fermenter. If you are confident in your primary fermentation vessel's ability to handle the beer without any off flavors or excessive sediment, it may be more practical to skip the secondary fermenter altogether.
In my own brewing experience, I have found that the use of a secondary fermenter can be beneficial for certain beers, particularly those with higher original gravities or when aiming for a crystal clear final product. However, I have also brewed many batches where I felt that the use of a secondary fermenter was unnecessary and opted to package the beer directly from the primary fermentation vessel.
The decision to use a secondary fermenter ultimately depends on the specific characteristics and goals of your beer, as well as your personal preferences and practical considerations. While it can be a useful tool for mellowing flavors and achieving clarity, it is not always necessary or beneficial for every batch.