Chinese consumers are seen as volatile and fickle - and companies are racing to keep up with their changing tastes

When Chinese President Xi Jinping dropped in for a pint at an English country pub with British Prime Minister David Cameron in October, few could have predicted it would start yet another Chinese consumer craze.

Within a few weeks, monthly China sales of the particular beer - Greene King IPA - soared from 6,000 bottles to 80,000 bottles a month.