Whisky Magazine Issue 120
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A look at different types of mash tun and how each accomplishes the job of mashing
Mashing may seem an entirely pragmatic process: adding hot water to malted barley in order to convert starches within the barley into sugars, which dissolve to create a sugary liquid known as wort, that drains from the mash tun (usually a large stainless steel vessel). But mashing is also a vital stage in attaining spirit with a consistent character and quality, and different mash tuns also have their own parameters. The more historic type is known as a traditional mash tun, with the alternative being a lauter, which was more widely used from the 1980s-90s.
Whichever type of mash tun is used the process begins in the same way: hot water and grist (ie. malted barley which has been milled) are combined in a separate tank called a mashing machine above the mash tun. The resulting ‘mash' is conducted through a spout into the mash tun. From this stage the type of mash tun determines how the process continues.
A traditional mash tun means a large vessel fitted with a central column that operates a ‘rake' mechanism, comprising curved steel arms possessing comb-like teeth. The arms rotate around the mash tun, the action resembling a swimmer doing front crawl, which stirs the mash and consequently aids drainage.
“Once the mash tun is three-quarters full we turn on the rake and give the rake three revolutions, which takes a few minutes. It's a very gentle stirring action, then we leave the mash sitting for half an hour before we start draining off the wort,” says Gavin McL...