Which ingredient is not part of the Hot Horchata recipe?

In a traditional Hot Horchata recipe, the primary ingredients often include rice, water, cinnamon, and sometimes sugar to sweeten the beverage. Cinnamon is a key flavor in horchata and is essential for creating its signature taste. Brown sugar can be used for sweetness, but it's not the only option; white sugar is commonly used as well.

White chocolate, while a tasty addition to many desserts and drinks, is not typically included in a classic horchata recipe. It can alter the original flavor profile, which is meant to be creamy and lightly spiced. Caramel, similarly, is more of a modern twist and doesn't align with the traditional methods of preparing horchata.

Therefore, brown sugar is the ingredient that is often thought of in variations or alongside other sweeteners but is not essential to the base recipe. This makes it the ingredient that does not traditionally belong in the Hot Horchata preparation.