The starch in barley can be used as nutrition for the yeast when producing alcohol, but first the starch must be converted into sugar. This is done by malting.

Today only a few distilleries bother to make their own malt in the traditional way and in most cases it’s only for a part of their need. The rest of the malt is produced at large maltings with modern process equipment, however, according each distillery’s own specification.

BARLEY

Is well suitable as a raw material for production of alcohol due to it’s high content of starch, as well as an efficient system for the conversion of starch into sugar. The best barley comes from meagre soil since rich soil with a high nitrogen content promotes protein at the expense of starch.

Traditionally the barley was grown locally, but today the greater part comes from England, other EU countries and even farther away. According to many whisky producers the type of barley has little to do with the final quality of the whisky, although it is significant for the quantity. Nevertheless, a few distilleries put a lot of effort into the selection of barley.

TRADITIONAL STEEPING

The barley is soaked in water in a steeping vessel for 2-3 days. It is allowed to absorb enough water for the germination to start, this is also when enzymes in the grain are activated. The water is drained off and the steeped barley is spread out on the malting floor for germination.

TRADITIONAL GERMINATION

The seed inside the barley has now started to sprout. It needs nutrition and different enzymes are produced and activated in order to achieve this. Glucanase (cytase) breaks down the cellulose surrounding the starch, thus making it accessible. Amylase (diastase) converts the starch first into dextrin, a soluble form of starch, and then into maltose, a readily soluble sugar.

The barley is frequently turned in order to get even temperature distribution and aeration as well as preventing the rootlets from being entangled. The germination takes 8-12 days and is terminated before the seed consumes too much of the dextrin. Our precursor for sugar is now called green malt.

TRADITIONAL KILN DRYING

In order to stop the seed growth and temporarily halt the enzyme activity the moisture content has to be reduced, this is done in a kiln. Even if most distilleries don’t malt themselves, they still have kept these buildings, easily recognisable by their pagoda-shaped roofs.

The green malt is spread out on a perforated floor placed above a furnace. The fire is fed with coal, coke or similar together with peat for the first part of the kilning. Heat and smoke are transferred through the bed of green malt, the pagoda head ventilates the room but not so efficiently that the smoke is drawn out at once.

The amount of peat and the time it is used will determine the final smokiness of the whisky. For a lightly peated whisky the time is only a few hours, this results in a crisp malt with a rather sweet taste. For a heavily peated whisky, the time is the main part of the total 48 hours of kilning. This malt has a very smoky taste with reduced sweetness.

Smokiness used to be one of the things that characterised Scottish whisky and distinguished it from Irish. It is still considered to be so unusual that one distillery that makes whisky from unpeated malt uses this in their promotion. It is in fact not at all uncommon, and the use of unpeated malt seems to increase. Many distilleries that claim to have a low peatiness level do not use peat at all.

PEAT

Consists of vegetable matter, which has been decomposed and partially carbonised. It forms mosses that are found in many parts of Scotland, from where it is cut and dried before use. Peat has traditionally been a major fuel source and is still used.

Depending on age, location and what depth the peat is taken from, it will show different characteristics. Peat from Islay and the coastal region contributes to these whiskies tar-like smokiness, while inland peat with character from grass and heather results in a less pungent smokiness.

MODERN MALTING

Large malting facilities produce the major part of the malt used by the distilleries. Each distillery has their own specification after which the barley is malted. The use of centralised maltings may result in a standardisation since local varieties of peat and water are given less significance, but the industry claims it doesn´t.

The modern maltings still use the old principles, only with modern process equipment and on a larger scale. The common method is known as drum malting where the processes are performed in large vessels. A more recent method is called SKGV, Steeping Germinating Kilning Vessel, where all the mentioned processes are performed in the same vessel. The green malt is dried using hot air but peatiness can still be achieved by mixing peat smoke with the air.

The starch in the seed must first be converted to sugar. The first step is steeping the barley in water, this activates enzymes inside.

The barley is then spread out on floor for germination. The starch is first changed into dextrin and later into sugar. The sprout is growing inside, feeding on the dextrin.

The green malt, as it is now called, is dried after 8-12 days in order to stop the process before the sprout consumes all the dextrin. This is done in a kiln with the pagoda-roof so typical for Scottish distilleries.

Smoke from coke and peat is led through a bed of green malt. It is the peat that gives Scotch whisky its smokiness. The dried green malt is called malt.

Only a few distilleries still maintain the traditional way of malting as described above. The common way is to buy the malt from large malting facilities.