Beer purists are aghast at the sight of microbrew varieties in stores this August featuring hints of “cinnamon, nutmeg and a touch of cardamom and clove.” While bars are still pouring light summer fare — mango hefeweizens, goses and blonde ales — supermarkets and liquor stores are increasingly adopting back-to-school-type promotion strategies in bringing pumpkin beers, amber harvest ales and Oktoberfests onto store shelves well before the leaves turn to gold.