What is the history of rice coffee?

There is no known historical record or established tradition of a beverage called "rice coffee." It's possible that you are thinking of a similar beverage or that there is a misunderstanding in the terminology.

Here are some possibilities:

* Rice-based coffee substitutes: During times of scarcity or when coffee was expensive, some cultures developed substitutes using roasted grains like barley, chicory, or even rice. These were often brewed like coffee and could be used for flavoring or as a caffeine-free alternative.

* Coffee blended with rice: In some regions, rice might be added to coffee during brewing, perhaps for textural purposes or to dilute the coffee's strength. This practice, however, is not widespread and doesn't have a specific name like "rice coffee."

* Misinterpretation of terms: Perhaps you are encountering a translation issue or a regional name for a different coffee-related product.

If you can provide more context or details about where you heard the term "rice coffee," it might be possible to clarify what you're referring to.