Learn Icelandic: Hvernig er kaffið?

Hvernig means "how". It is used exactly like in English to ask about the state, condition, or quality of something, such as asking how a drink tastes or how someone is doing.

Is the word order in this Icelandic question the same as in English?

Yes! Just like in English, an Icelandic question of this type starts with the question word (hvernig), followed by the verb (er), and then the subject (kaffið).

Why is the word for coffee written as kaffið instead of just kaffi?

In Icelandic, the word for "the" (the definite article) is attached to the end of the noun instead of being a separate word before it. Kaffi means "coffee", and adding the suffix -ð makes it kaffið, meaning "the coffee".

Is er the exact equivalent of the English word "is" here?

Yes, it is. Er is a form of the verb vera (to be). It is the correct form to use when talking about a third-party singular subject like "he", "she", or "it" (in this case, the coffee).