In whisky-making, after the malting process comes the mashing process. Silvano Samaroli briefly discusses the intricacies of the mashing / infusion cycle.

For better or for worse, in a traditional or industrial way, we got nice and dry malt, friable and aromatic. The transformation, moreover, is clearly visible: the green barley was woody and elastic, while the malt is now crisp and fallow.

After removing the rootlets and other impurities, the malt is ground and takes, as we have said, the name of “grist".

Rootlets, or "malt culms", are the first by-products of manufacture and are used as feed for cattle. Chemically speaking, mixing or "mashing" consists of the hydrolytic cleavage of starch, proteins and other biopolymers contained in grist.

These days, distilleries that purchase ready-made malt from centralized malt houses by forced germination begin their operation only at this point, which is to say at the process of mashing. Grist is introduced into a large vat (the "mash tun" or "mixing vessel") in which, simultaneously, hot water that allows for the transformation of dextrin in maltose, which had already begun during the malting process, is pumped. The extraction of the maltose is then seen to, separating it from the solid waste. The separation is usually carried out in four phases. And each time at a different temperature, that ranges between 70 and 80 °C.

The liquid which is obtained in these phases, called "wort", is drained into an underlying vat called "underback". The wort deriving from the first phase is the most highly concentrated, while the result of the following steps - weak wort - is more diluted. The product of the first two washes goes directly to fermentation, while the latter are recycled and used for successive mashing.

The dregs, made up of the solid parts of the grist that remains at the bottom of the vat, are also destined for livestock feed, same as malt culms.

Written by Silvano Samaroli

The text is an excerpt from "Whisky Eretico" (pp. 51 - 53), written by Silvano S. Samaroli, published 2017 by The Whisky Library, The Library Group Limited.