taiwan information - beverages, what to drink
As Taiwan is a subtropical island with the south part in the tropics, it cannot hurt to drink a lot, especially during summertime. Drink vending machines can be found virtually everywhere and are filled with all kinds of juices, tea and coffee drinks, soy milk and mineral water.
Water
As a general rule, tap water in Taiwan is unsafe and should be boiled for at least three minutes and preferably filtered before consumption. The locals do it, and so should you.
The good news is that finding safe water is rarely a problem. Any water or ice you are served in restaurants will already have been processed. Water fountains in Taiwan always incorporate filters, and they can be found in practically every lodge or hotel as well as (for example) larger museums and Taipei MRT stations. If you can't find one, then you should buy bottled water.
Note that in Kaohsiung, most people do not drink the tap water, even after filtering or boiling, since the water contains trace amounts of arsenic that is detrimental to ones health. Whether the trace amounts are dangerous or not is debatable, especially if you're just passing through, but the locals obtain potable water using pumps that look like gasoline pumps that are strewn throughout the residential areas.
Alcohol
Traditional alcoholic drinks in Taiwan are very strong. Kaoliang 高粱酒 is the most famous alcoholic drink. A distilled grain liquor, it is extremely strong, usually 140 proof or more, and often drunk straight.
Taiwan also produces many types of Shaoxing 紹興酒 rice wine, which are considered by many as being some of the best in the world.
Taiwanese people enjoy beer on ice. A wide variety of imported beers are available, but the standard is Taiwan Beer 台灣啤酒, produced by a former government monopoly. It is brewed with fragrant penglai rice in addition to barley giving it a distinctive flavor.
Tea and coffee
Taiwan's specialty teas are High Mountain Oolong (高山烏龍, Gau-shan wulong) - a fragrant, light tea, and Tie Guan-yin (鐵觀音) - a dark, rich brew. Enjoying this tea drank in the traditional way using a very small teapot and tiny cups is a experience you should not miss. This way of taking tea is called lao ren cha - 'old people's tea', and the name is derived from the fact that only the elderly traditionally had the luxury of time to relax and enjoy tea in this way. Check the small print when visiting a traditional tea house though: in addition to the tea itself, you may be charged a "water fee" (茶水費) for the elaborate process of preparing it as well as for any nibbles served on the side.
Pearl milk tea (珍珠奶茶 zhēnzhū nǎichá), aka "bubble tea" or "boba tea", is milky tea with chewy balls of tapioca added, drunk through an over sized straw. Invented in Taiwan in the early 1980s and a huge Asia-wide craze in the 1990s, it's not quite as popular as it once was but can still be found at nearly every coffee/tea shop. Look for a shop where it is freshly made.
The cafe culture has hit Taiwan in a big way, and in addition to an abundance of privately owned cafes, all the major chains, such as Starbucks, have a multitude of branches throughout major towns and cities.
Soft drinks
Taiwan is a great place for fruit drinks. Small fruit-juice bars make them fresh on the spot and are experts at creating fruit-juice cocktails (non-alcoholic, of course). zong-he - mixed - is usually a sweet and sour combination and mu-gwa niou-nai is iced papaya milk. If you don't want ice (though it is safe in Taiwan, even at road side vendors) say, chu bing and no sugar - wu tang.
Soy milk, or doujiang, is a great treat. Try it hot or cold. Savoury soy milk is a traditional Taiwanese breakfast dish. It is somewhat of an acquired taste as vinegar is added to curdle the milk. Both sweet and savory soy milk are often ordered with you-tiao, or deep fried dough crullers.
There are a lot of pseudo health drinks in Taiwanese supermarkets and convenience stores. Look out for asparagus juice and lavender milk tea for example.