Definition of “brew” - Learner’s Dictionary

brew

verb uk us /bruː/
BEER [ T ]

to make beer

TEA/COFFEE [ I, T ]

If you brew tea or coffee, you make it by adding hot water, and if it brews, it gradually develops flavour in hot water.

be brewing

If something bad is brewing, it is beginning to develop:

There is a row brewing over the plans.

(Definition of “brew verb” from the Cambridge Learner's Dictionary © Cambridge University Press)