Wine glass etiquette

Last week I dropped in on the Hungarians' annual London tasting, in what I believe is the capital's finest setting for a wine tasting – the recently renovated Floral Hall in Covent Garden, now a huge, airy meeting place and bar for the Royal Opera House. What makes it superlative for tasting is the vast glass barrel-vaulted ceiling which allows an unusually useful amount of natural light on to the tasting glass.

Speaking of which, I was taught quite a lesson there. I approached a new producer's table and presented my glass, bearing traces of the delicious Cabernet Franc Selection...