When using the salt test to check for beer cleanliness, what indicates that a glass is not beer clean?

When performing the salt test to evaluate the cleanliness of a glass, the observation that salt adheres only to certain areas is significant in indicating that the glass is not beer clean. Beer cleanliness refers to the absence of residues, contaminants, or oils that can affect the head retention and overall appearance of the beer.

In a clean glass, salt should distribute evenly, suggesting that the surface is free of contaminants. If salt only sticks to certain parts, this uneven distribution indicates the presence of residues or contaminants, creating hydrophobic (water-repelling) areas that disrupt the ideal surface for serving beer.

The other outcomes observed during the salt test provide different insights. For example, if salt dissolves immediately, it typically indicates that the surface is wet and possibly not ideal for beer, but it may not definitively signal that the glass is dirty. Similarly, if salt forms a thick layer, it could imply residue, but it doesn’t necessarily register the degree of cleanliness as the patchy adherence does. Lastly, while salt making the glass feel rough might provide sensory feedback, it’s less direct than the visual assessment of uneven adherence. Thus, the identification of salt adhering to specific areas is the most telling sign of a glass that is not beer clean.