What is a key characteristic of a clean beer glass during consumption?

A key characteristic of a clean beer glass is that lace adheres to the sides after each sip. This "lace" refers to the remnants of the beer's foam that remain clinging to the inside of the glass as the liquid is consumed. Having lace indicates that the beer is properly carbonated and the glass is clean.

In contrast, if a glass is not adequately cleaned or has residual oils or detergents, this can prevent the beer's foam from forming correctly, resulting in no lace or less visual appeal. The presence of lace enhances the overall experience of drinking beer, as it signifies a good quality pour and an enjoyable texture.

Other characteristics, such as a dry glass or bubbles clinging to the sides, can suggest issues with cleanliness or carbonation. For example, bubbles clinging to the sides may indicate that the glass is contaminated with oils or residues. Lastly, if the head dissolves immediately, it can signify poor carbonation or an unclean glass, which detracts from the drinking experience. Therefore, lace formation is a clear sign of a well-poured beer in a clean glass.