Astringency

Years ago I recall being told that astringency was one of the basic tastes, along with bitter, sour, sweet and salty. Since then, its place on that list has been taken by umami.  Astringency has since been considered a tactile sensation, with similar physiological mechanisms as pain, heat, cold, and pressure. Despite this reclassification and the scientific progress in elucidating some of these mechanisms, there are still many questions that need to be answered. The general phenomenon is defined by the Merriam-Webster dictionary as “tending to pucker the tissues of the mouth”. This isn’t an ideal description of the term as it applies to the food and beverage sensory industry since we know that polyphenol-based astringency sensation does not involve any physical changes in the tissues of the mouth like the traditional astringent alum would produce. A somewhat more applicable use of the term for our purposes is “a compound which precipitates proteins and has a molecular weight over 500”.[1]   However, even this definition has limitations, as there are some curious results which defy explanation at the moment.