Bottom fermented, you say?

A bottom fermented beer is fermented with a yeast strain called Saccharomyces Carlsbergensis. It ferments at around 14°C, giving low production of esters and flavours.

On the contrary, top fermented beers are generally called ales and are fermented with the strain Saccharomyces Cerevisiae. They ferment at a higher temperature of 20-24°C, giving much more flavour to the beer.