Benromach has four wooden larch washbacks, which were resized using the wood from the distillery's original washbacks. Each washback has the capacity to hold 11,000 litres of worts. Two varieties of yeast, brewers and distillers, are added to the worts to start the fermentation process. Fermentation lasts between three and five days and the product that is left is a weak, beer-like solution now called wash. This is now transferred, or charged, to the wash still for distillation to commence.