In Wolfburn Distillery the manager told me it is the strike temperature that is important ~ this means the temperature when the hot water first goes through the grist, the malted barley.
The strike is when the conversion happens. When the hot water hits the malted barley it sets off a reaction. This is when 90% of the conversion of the sugars occurs.
In Ardnamurchan Distillery they told me that the size of their mash tun was governed by the size of the road coming into the area. A bigger mash tun would mean a bigger lorry and it would not have been able to drive up the roads of the Ardnamurchan peninsula to the distillery.
The mash tun at Ardnamurchan holds 2 tonnes of grist and drains 10,000 litres to washback.
When Alfred Barnard was in Jura in 1886 the stirring gear in the mash tun was turned by a water wheel.