The head of a pot still is connected to the condensing system by a simple copper pipe called a lyne arm or lye pipe. But this insignificant-looking tube can have quite an influence on the flavour and style of the spirit.
In its simplest form, the lyne arm is a cylindrical copper tube that, as it leaves the head of the still, either (a) angles upwards; (b) is horizontal; or (c) angles downwards.
With (a), the steeper the upward angle, the more reflux is created – in other words, the more the spirit vapours that condense on the inside of the pipe will trickle back down into the body of the still again. This will help to create a lighter spirit.
But, in the case of (c), the downward angle of the pipe reduces reflux and instead encourages ‘carryover’, where more of the heavy oils trickle down towards the condenser. This will help create a heavier, sometimes nutty spirit.
Lyne arms are an important detail in the picture of making malt whisky, but they’re just that: a detail. There’s a lot more going on in the distillery, both because of the equipment and because of the human beings who operate it.