The distillery’s original mash tun was a small, hand- turned wooden vessel. Operating this primitive apparatus was a tiresome task, and the resulting mash was frequently lumpy with sugars poorly extracted. When John Maitland instigated his renovation and modernisation of Jericho in the late 1860s, an easily- cleanable iron tun was installed, measuring twelve feet in diameter and four feet in depth. The new tun had a mill-driven mechanical arm with revolving stirring gear attached. The rakes turned the mash, an automated process that offered better extraction of sugars and more consistent wort.