In the literature on coffee chemistry, particularly in William H. Ukers’ "All About Coffee," the word "solubility" is employed in diverse yet interrelated ways. For instance, solubility is presented quantitatively in tabular form to showcase the varying capacity of a solvent to dissolve caffeine under different conditions [1], and it is further detailed by outlining the specific amounts of solvent, temperature, and resultant solution measurements [2]. Moreover, solubility is also addressed through experimental determination, as illustrated by Seidell’s methodology for assessing the dissolution of caffeine [3]. Together, these examples reveal a multifaceted approach to understanding solubility, one that combines data presentation with empirical testing to elucidate the behavior of caffeine in solution.