ArticleUnderstanding Polyphenols Understanding Polyphenols Polyphenols present a classic dilemma for the brewer. On one hand, they taste bad. These bitter, astringent compounds— tannin is probably the best-known form of polyphenol — can ruin theAlready a member? Log InWritten by Randy WhistlerYou'll Also Like Article MEMBERS ONLY Hop Extracts - Advanced Brewing These hop extracts roughly fall into two categories, those primarily intended to add bitterness and those where aromatics are the goal. Article MEMBERS ONLY Insulation for Single Vessel Brewing What’s the best way to hold a consistent mash temperature for brew-in-a-bag brewing? We put the popular Reflectix insulation to the test.