I've seen other sites have some success via regular events, e.g. World Building or Code ReviewsCode Reviews.
Alternatively we can cross our fingers and hope for a major new coffee product, for which we can quickly position ourselves as the de-facto help resource, but that seems like wishful thinking.
However if one does come about (or some other, similarly major coffee-related event occurs), then we should be sure to position ourselves as the best resource out there by quickly producing a comprehensive set of questions and answers on all facets of the new subject.
One thing to note is that more questions will tend to lead to more users, and vice versa, as more questions lead more people to the site via google and more users post more questions.