Horchata varies by region. The one I'm familiar with, from Spain, is based on tigernuts. It's a very traditional summer drink and frankly you won't find a diffe

Horchata varies by region. The one I'm familiar with, from Spain, is based on tigernuts. It's a very traditional summer drink and frankly you won't find a different kind of horchata in Spain, unless you search for it in ethnic stores (and even so I'm not sure where I would look for it). Apparently horchata in Mexico is based on rice, and I don't know if there aren't any other versions. I haven't tried rice based horchata, but it soudns very different from the Spanish one, and I'd like to try it some day. I don't know about how has the term evolved in the English speaking word, but no one in Spain will refer to horchata as milk, nor do we use it as a milk replacement (nobody would mix it with coffee, for example). Also we don't use the term as a generic word for vegetal milk at all. Milk and horchata don't really have anything in common aside from being white drinkable liquids.