Rodent circling key hotel where brewer keeps grain (4-5)

'brewer keeps grain' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'rodent circling key hotel' is the wordplay.
I cannot really understand how this works, but
'key' could be 'alt' (I've seen this in other clues) and 'alt' is found within the answer.
'hotel' could be 'h' (phonetic alphabet: alpha, bravo, charlie etc.) and 'h' is found in the answer.
'rodent' could be 'mouse' (mouse is a kind of rodent) and 'mouse' is found in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...

'where' is the link.

Can you help me to learn more?