Why is it important to wash glasses with non-petroleum based soap?

Washing glasses with non-petroleum based soap is crucial because petroleum-based soaps can leave behind residues that may affect the flavor and aroma of beer. When these residues make contact with beer, they can introduce unwanted off-flavors and aromas, which are detrimental to the overall tasting experience. Beer is a delicate beverage, and even minor impurities can interfere with the drinker's perception of its intended flavors. Therefore, using a soap formulation that does not contain petroleum ensures that glasses are thoroughly cleaned without any lingering substances that could alter the quality of the beer being served. This practice helps ensure that the beer showcases its true characteristics without interference, which is essential for providing a top-notch tasting experience.