Peat and its importance in whisky
Large parts of Scotland are covered by bogs with a peat layer several metres thick. This has formed over the past 1,000 to 5,000 years from dead plant remains. Each bog grows by about one millimetre per year. If a bog is 3 metres thick, it is therefore around 3,000 years old.
People in Scotland have been using peat as a source of energy since time immemorial. Peat is cut into narrow strips and piled up in small pyramids to dry. The water drains out of the peat very quickly and turns the soft strip into a hard briquette. Similar to coal, this briquette contains the energy of the dead plant remains.
Unlike coal, dried peat burns quickly and releases a large amount of energy in the form of heat. Anyone who has ever sat by a peat fire in Scotland in the evening can confirm its warming power.
Smoke flavour in whisky
What is peat used for in whisky production and how does the smoky flavour get into the whisky? The old Scots used peat to heat the stills. However, this does not result in the smoky flavour of the whisky. Does the water that flows through peat bogs have an influence on the smokiness of the whisky? The answer is a clear NO! Peaty water only contains a few ppm (parts per million) of peat, which colours the water brown but does not contribute to the smoky flavour in any way. Of course, the water is of decisive importance for the quality of the whisky, but it has no influence on the smokiness. Only the drying of the wet malt over peat-heated fires brings the smoke into the barley grain. If you would like to find out more about malting, we have a detailed article for you here.
The difference in the smokiness of the whiskies is due to the length of time the barley grain is exposed to the acrid peat smoke during the drying process. The kilning time for wet malt is around 30 hours. Of these 30 hours, Laphroaig is kilned over a peat fire for around 18 hours, whereas Glengoyne is kilned over an unpeated fire. This results in a wide range of whiskies, from extremely smoky whisky to whisky with almost no smoke. Malt grains have a special feature. Even without a peat fire, they impart a hint of smokiness to the whisky.
The mass production of Scotch whisky over the past 200 years has driven up the demand for smoky whisky enormously. The distilleries on the island of Islay in particular produce highly smoky whisky. Above all Laphroaig, Lagavulin, Caol Ila, Ardbeg and Bowmore. The smoky flavour of these whiskies is so strong that even when diluted 1:20 with water and mild grain whiskies, they give the Scotch the desired, distinct smoky note.
Modern peat extraction methods allow the peat layer to be extracted over a large area, as shown in the following pictures. The extraction process is not similar to open-cast lignite mining, but more like harvesting a cultivated foodstuff. The agricultural machinery used for extraction certainly contributes to this.
The briquettes (they are still briquettes even after 200 years) are still dried in large piles from which the water flows out according to the laws of gravity.
The whisky industry endeavours to reduce the consumption of peat through various processes. The Bowmore distillery, for example, grinds the peat into a coarse-grained powder that is placed on a normal fire and produces the necessary smoke. This increases the smoke yield of the peat. However, modern large-scale maltings such as Port Ellen, Glen Esk and Glen Ord also utilise the peat far better in an industrial way than is the case on a conventional dry fire in the kiln of the distillery. In a closed system in a large malting plant, the smoke does not escape into the environment via the pagoda roofs of the kiln after a single contact with the grain, but is instead channelled over the barley grains until the smoke is optimally utilised. The distilleries ordering the malt specify the smoke specification for the malt required by the malting plant so that their whisky has exactly the desired flavour.
But there are also critical notes! The heavy consumption of peat for the production of malt has already significantly affected some peat deposits. Peat is no longer being mined near Campbeltown, so peat is being transported from further afield, for example from the island of Islay.
But don't be afraid of the future! Projections have shown that more peat will grow back in Scotland than will be extracted by the whisky industry.
