a question for British peoples

rachmaninoff

So I was watching CSPAN2, and all these British officials had these strange water bottles like they don't have in the states, some were made of glass and at first I thought they were vodka, which is an odd thing to drink when you're on TV. There was a name or brand on one of them, it was 3 or 4 letters long and started with "B", does anyone know what it was and why it was in a glass bottle?