In considering the human body’s demand for food and nutrition, the simple need for liquid refreshment is sometimes overlooked. Although this fundamental physiological requirement can be satisfied by drinking an adequate supply of pure water, most people, when given a choice, prefer to achieve the required level of liquid intake with a variety of flavored drinks to stimulate the palate.

Soft drinks are usually defined as nonalcoholic, water-based drinks, although a few may contain alcohol, albeit in quantities too small to warrant their classification as “hard liquor.” Soft drinks are usually sweetened – soda water being an obvious exception – and flavored with food acids, essences, and sometimes fruit juices. They are often carbonated – that is, charged with carbon dioxide gas – and, indeed, in North America are referred to as carbonated beverages. In some countries, including the United Kingdom, there is a significant retail market for concentrated soft drinks intended for dilution at home before consumption. Soft drinks in powdered form are similarly marketed for preparation at home. In addition, uncarbonated, ready-to-drink soft drinks are also found.

The flavors of soft drinks may be derived from fruits, nuts, berries, roots, herbs, and other plants. Moreover, fruit (and to some extent vegetable) juices, as such, have grown in popularity in recent years and have come to be included among the soft drinks. In many countries, soft drinks are distinguished from hard liquor by the higher taxation of stronger drinks, for example through excise duties, and the term “nonalcoholic” can sometimes mean merely “non-excisable.” However, soft drinks are frequently subject to other taxes, though usually at lower levels than those that are levied on alcoholic drinks. Soft drinks are often distinguished from medicines by legislation. In the past, these distinctions were less precise, and a historical study of soft drinks will include products that began with a mainly medicinal purpose but are regarded today as simple refreshment.