Which of the following Belgian beers is always made with wheat?

Witbier is a style of Belgian beer that is indeed always brewed with a significant proportion of wheat, typically comprising around 30-50% of the grain bill. This use of wheat contributes to the beer's characteristic haziness and light body, as well as its refreshing and slightly tart flavor profile, often enhanced by the addition of spices such as coriander and orange peel.

In contrast, the other styles mentioned—Dubbel, Saison, and Tripel—are primarily made with barley malt and do not inherently require wheat in their brewing process. For example, a Dubbel is a dark, rich beer with caramel and dark fruit flavors, typically brewed using pale and caramel malts rather than wheat. Saison, a farmhouse ale, can contain a variety of grains but wheat is not a defining ingredient. Similarly, Tripel is a strong pale ale known for its fruity and spicy flavors, also predominantly made with barley malt. Thus, the distinction lies in the fundamental ingredient composition of Witbier that sets it apart as a wheat beer.