Malt is the result of the malting process. The barley is made wet and spread on the malting floor to allow the germination process to start. A succession of chemical reactions change the starch contained in the barley in sugar. Later sugar will change into spirit.
The malting art consist of finding the right moment to stop the germination process: not too late but not too early.
According to the season, malting takes between 8 and 21 days. Constant attention has to be given to the process. Barley has to be turned over regularly to ensure a constant moisture and temperature and to control the germination of the barley grains.
The end of the germination is triggered by drying the germinating barley over a fire (kiln). This oven is often heated by peat. The smoke of the peat fire in the kiln is determining is the taste of many a whisky.
Germination is stopped by drying the grains above an oven (kiln). The kiln on the picture is the one of Laphroaig. A kiln was often fed with peat. It is the smoke of the peat fire which gives some whiskies their particular flavour.
The art of some distilleries is in the correct proportioning of peat used to dry the malt. Springbank for instance produces 3 different malts: Springbank, Longrow and Hazelburn (which will be available from 2006). One of the main differences between those 3 products is the proportion of peat used for drying the malt. There are also some other differences in the distillation process in the case of Springbank. Bruichladdich also produces 3 different whiskies with different peat levels: Bruichladdich, Port Charlotte and Octomore.
Economic reasons obliged most of the distilleries to abandon their malting floors during the 1960's Malting happens mainly at specialized plants, called maltings. This maltings produce malt according to the requirements of their clients. The same malting company produces thus several kinds of malt. There are however notable exceptions to that rule: Balvenie, Laphroaig, Highland Park, Bowmore are some of the distilleries which produce parts of their own malts. According to some sources, these distillery would produce about 30% of their needs. Springbank produces 100% of their malt.
Maltings can be independent, or belong to big concerns, owning their own distilleries, like Diageo. Diageo, who owns a great deal of the Scottish distilleries (see distillery owners) has created its own malting plants, to supply the distilleries of the group (like for instance the malting at Glen Ord) or for local distilleries, like the Port Ellen Maltings on Islay.
The latter is the result of an agreement signed by all the Islay distilleries who oblige themselves to buy a certain amount of malt at the Port Ellen Maltings. This malting plant is in full expansion, just like the distilleries of the island, and is progressively occupying the territory of the (henceforth former) distillery of Port Ellen.
The maltings do not have the romantic aspect of (old) distilleries, with their pagoda roofs...
When the malt is dry, it is grinded to make a kind of coarse flour which will be used in the next operations.
This flour is called grist.
Malt grinding is done with a malt mill in the distillery itself.
Nearly all the distilleries use the same kind of mill, traditionally made in England, in Leeds, which is sometimes hard to accept for a real Scot.
The grist will be mixed with hot water in the mash tun. Generally one volume of grist is mixed up with 4 volumes of water. In this operation, 3 successive waters are used, at a temperature between 63 and 95%
A mash tun can contain up to 25000 litres and has a double bottom with thin perforations to let the wort (sugared liquid resulting of the brewing operation) flow out, retaining bigger parts which will be sold as cattle food. In order to facilitate the process, mash tun have rotating blades. The waste is called draff.
The first operation, taking about 1 hour, will change the starch in fermenting sugars. The mix of water and grist looks like a kind of traditional porridge.
This sugared juice is called wort. The remainders will be brewed 3 to 4 times, in order to get a maximum of wort.
The quality of the wort is controlled by the excise men, because it determines the amount of spirit which will finally be produced. This is the base of the taxation of the distillery. .
The wash back
In order to start the fermentation of the wort, yeast is added.
The action of the yeast on the sugar of the wort will produce alcohol and carbon dioxide. The wort starts bubbling, which will sometimes result in strong vibrations of the wash back, despite its impressive size. Traditional wash backs are made of Oregon pinewood or scottish larch.
However, more and more stainless steel wash backs are used nowadays, because they are easier to maintain.
The result of the fermentation is the same in both kinds of wash backs. However, lots of distilleries pretend Oregon wood is much better, and even hi-tech distilleries like Caol Ila do not believe in stainless steel wash backs
As result of the fermentation of the wort, a kind of beer with a percentage of approximately 8%. Till now, there are no substantial differences in the process of making whisky, and the making of beer.
From now the difference between the process will become obvious. Beer will be perfumed with hops, while whisky will be distilled without alterations.