In a nutshell: barley contains starch which must to be converted into soluble sugars to make alcohol; in other words, barley must undergo germination.

The type of barley used is a key decision for the distiller and most will go for a type that yields a high amount of a sugar at the lowest price. The better the quality, the higher the sugar yield.

After it has been screened to remove foreign matter, the barley is soaked for 2 to 3 days in warm water and then traditionally spread on a concrete floor of a malting house. The process of soaking is called steeping. It is turned regularly to maintain a constant temperature and to control the rate of germination.

Malting Floor at Highland Park Distillery

On a commercial scale, this happens in large rotating drums or large rectangular boxes called Saladin, where temperatures are controlled by blowing air upwards through the germinating grains.

A Saladin

You can imagine that this process is rather time consuming and so more recently, owing to the huge demand for Scotch Whisky, distilleries have been obtaining their malt from centralised maltings which supply a number of distilleries, making malting more economical.

It takes roughly 8 to 12 days for germination to start happening; the weather and quality of the barley, among other things impacts on this process. The most important thing about germination is the secretion of an enzyme called diastase making the starch in the barley soluble. This is a key step in getting it ready to convert to sugar.

Germinating Malt

As the barley starts to shoot, germination has to be stopped by drying it in a kiln, a Saladin box or in drum maltings. The last 2 happen mechanically. Traditionally peat is used to power the kiln and it is at this point where the type of peat used and length of drying in the peat smoke can influence the flavour of the final spirit. The barley is now called 'malt' and this is ground down in a mill, with any husks and other debris being removed until grist is produced. What is grist? You can find out in the next post but for now here's a rather nice clip of the process (although you only need watch the first minute of it for Malting!)