Strolling along Collins Avenue you can single out Argentines from other Latin Americans by the telltale gourd in hand filled with a stuff called yerba maté. This is not just a drink. According to those from the pampas, yerba maté is a gentle diuretic that possesses incredible powers: It stimulates mental alertness, aids in weight loss, cleanses the colon, energizes the body, accelerates the healing process, relieves stress, calms allergies, fortifies the immune system, and increases longevity (we dare any Chinese herb to beat that!). But drinking it also is a cultural and social affair dictated by rules of consumption. The Guarani Indians of South America were the first to begin sipping yerba maté (commonly known as maté), a practice that was picked up by the gauchos, who would share a maté around the campfire to enhance their communal bonds. (In traditional maté ritual, the cup often is shared among close friends and family using the same straw, or bombilla.) The characters in Robert Heinlein's Stranger in a Strange Land became "water brothers" and "water sisters" when they drank from the same maté gourd. Now you too can join the family. Buenos Aires Bakery offers the largest variety of maté brands: Taragui, Rosamonte, La Merced, Canarias, Nobleza Guacha, Union, and our personal favorite, Cruz de Malta.