Frescos, refrescos, and jugos naturales are favorite drinks in Costa Rica. They are usually made with fresh fruit and milk or water. Among the more common fruits used are mangoes, papayas, blackberries (mora), and pineapples (piña). You'll also come across maracuya and carambola. Some of the more unusual frescos are horchata (made with rice flour and a lot of cinnamon) and chan (made with the seed of a plant found mostly in Guanacaste definitely an acquired taste).
The former is wonderful; the latter requires an open mind (it's reputed to be good for the digestive system).Order un fresco con leche sin hielo (a fresco with milk but without ice) if you are trying to avoid untreated water. If you're a coffee drinker, you might be disappointed here. Most of the best coffee has traditionally been targeted for export, and Ticos tend to prefer theirs weak and sugary. The better hotels and restaurants are starting to cater to gringo and European tastes and are serving up better blends. If you want black coffee, ask for cafe negro; if you want it with milk, order cafe con leche.
If you want to try something different for your morning beverage, ask for agua dulce, a warm drink made from melted sugar cane and served either with milk or lemon, or straight.