The short answer is that wheat beers and white beers are the same thing, at least when referring to German and Belgian styles.
The answer gets a little more complicated, but first let’s define our terms:
hefe (German) – yeast
weizen (German) – wheat
weisse (German) – white
witbier (Belgian) – white beer
wheat beer (American) – a beer that often bears little or no resemblance to German wheat beers
A weissebier is German wheat beer made with at least 50 percent malted wheat, with the remainder being malted barley. It uses particular strains of yeast that produce chemicals that give the beer distinctive flavors, most notably clove, banana, and bubble gum. Outside of Bavaria, German weissbiers are generally called hefeweizens (literally “yeast wheat”), but weissbier, weizenbier and hefeweizen are all generally interchangeable. To make things a little less confusing for the remainder of this article, we’ll stick with hefeweizen.
A Belgian wheat (witbier) is similar to a hefeweizen, but are made using a different (but similar) yeast strain than the Germans use, giving them a different character. Belgian wheats also include orange peel, coriander, and other spices, lending them a much different character than hefeweizens.
And then there are American wheat beers and white beers. Some are faithful and delicious recreations of (or at least nods to) Old World Bavarian hefeweizens. Others are . . . not. In fact, some are technically not even wheat beer (using wheat just anywhere in the brewing process doesn’t make it a wheat beer), which is disappointing when you try one, and certainly not helpful when trying to decide which new wheat beer to try.
Many American wheat beers are brewed as such and rightfully called wheat beers, but since they are brewed with a different yeast, they often taste decidedly different than hefeweizens and witbiers. Many others use significantly less malted wheat than German hefeweizens.
To make matters a bit more confusing, many American wheat beers refer to their wheat beers as hefeweizen, weizen, or weiss—or use it somewhere in the name—implying much more of a similarity to German hefeweizens than what might actually exist.
This is not intended as American beer-bashing, which, by the way, is a darned popular pasttime in some online beer forums. Rather, it just comes down to what is true for a lot of things: meaning becomes squishy when popular terms are used for marketing purposes. If wheat beers are popular, marketers are going to take some liberties with wheat and its related terms.
Nonetheless, at least you have a rough idea of what constitutes a German hefeweizen/ weissebier/ weizenbier and and Belgian witbier. With American wheats and whites, you’re just going to have to glean all you can from the description on the label, get some recommendations, or try them.
As always, have fun discovering which ones you like best.