Pu'er (pu-ehr, puehr, puerh) teas are fermented teas that are almost exclusively produced in the Yunnan province of China. Production of pu'er teas includes a microbial fermentation process which can be applied to "sheng" green or raw tea leaves, or to "shou" cooked or black tea leaves. Both types of pu'er tea can be stored and aged, a process that improves both their flavor profile and their health benefits. Pu'er teas are prized both for their rich, complex and often earthy flavor, as well as for their health benefits which are believed to include cholesterol lowering, digestion aid, probiotic components, dieting and blood sugar control. Pu'er teas are available in loose-leaf form but are more commonly produced in compressed "cakes" or "nests" call tuocha.