The wort is filled into a washback, a large vessel made from wood or steel. Yeast is added, and again – depending on the distillery – variety is king: distiller´s or brewery yeast, the tribe, the amount, temperatures and duration of the fermentation differ from distillery to distillery. Some leave the liquid 40, others up to 100 hours in the washback before using it for the distillation. The liquid is called mash or beer – and tastes like (which is not really surprising, sharing the same production techniques up to this point).