Which of the following is an aspect of the proper procedure for changing a keg?

The process of changing a keg involves several specific steps to ensure safety and efficiency. Disengaging the coupler and removing the handle is a critical first step. This action releases the pressure from the keg and allows for safe handling of both the coupler and the keg itself. It is essential because it prevents beer from spilling and minimizes the risk of injury from pressurized gas or foam.

When changing kegs, proper techniques must be employed to avoid waste and ensure that the new keg is connected correctly. The other options present steps that are either incorrect or not standard practice. For instance, filling a keg with ice could cause temperature discrepancies and affect the quality of the beer. Keeping the old keg attached could lead to confusion about which beer is being served and potentially cause contamination. Finally, using a new coupler for each keg change is not necessary; a well-cleaned and properly functioning coupler can be reused safely.

Thus, option A clearly outlines an important step that aligns with industry best practices, ensuring an effective and safe keg change process.