The 4th element
If you have ever attended a tour of any of the Scottish whisky distilleries you ought to have heard the tour guide say - ”There are three things needed to make good whisky - water, yeast and malted barley”. Well, that IS true but to the inhabitants of Islay there is a fourth ingredient, well known to malt whisky lovers of the world... peat!
Large parts of Scotland (about 11% of which blanket bogs stands for 10) are covered by a layer of peat, usually more than one meter thick. This layer was formed during the last five thousand years. The peat was formed in waterlogged lands by partial degradation of organic matter and the composition of the peat depends on the micro climate and the specific flora in the different areas. Britain actually holds 13% of the worlds blanket bogs.
Peatlands are usually divided into bogs, fens, marshes and swamps. Bogs are formed in areas of heavy rainfall (therefore called ombrotrophic) and usually consists more of sphagnum moss and less of woody vegetation than the other types of peatland which usually are formed by waterlogging from the ground water (minerotrophic). Fens (also known as valley or basin bogs) contain more grass and herbal compounds. Marshes are treeless and intermittently waterlogged areas and normally the peat growth is very slow. Swamps are extremely minerotrophic and usually contain large amounts of wood material.
Average peat contains approximately 90% water and 10% dry matter, of which 92% is organic and 8% inorganic. Organic matter mainly consists of residues of lignin and other carbohydrates, but variations are vast depending on the local vegetation and the bog type. Ombrotrophic peats are usually richer in phenols and other aromatics, but due to the poorer vegetation they are low in carbohydrates, lignin and nitrogen. The acidity level is also high. The Islay peat has phenol levels of approximately 14.5% which is significantly higher than the mainland peats (<12%).
Western Scotland and the islands are especially abundant with blanket bogs and Islay is no exception. The growth rate of the moors is approximately one millimeter/year. If a moor is two meters thick it is therefore about 2,000 years old.
Peat and whisky
Since ”the dawn of time” peat has been used as a fuel in Scotland. Dried peat burns fast and therefore delivers a vast amount of energy in a very short time. Traces of old or new peat harvesting can be seen in most peat bogs all over Scotland. The peat is dug in narrow strips and subsequently piled in pyramids to dry. The water is rapidly lost, following the law of gravity, and the soft strips are turned into hard briquettes. A well planned peat ”harvesting” will allow the peat bogs to remain unharmed as the regrowth of peat will be at least as quick as its harvesting. So where does peat enter the whisky business? As a fuel maybe? Well, in the old days when there were neither oil nor electricity, peat was definitely the cheapest and most widely available source of energy. It was used to heat the pot stills but nowadays that is considered history. Peat has been put aside and newer energy sources like electricity and steam has entered the scene. So, why is peat still important? Well, the answer is – phenols! Drying the damp malted barley over a slowly burning peat fire adds a peaty, smoky aroma to the finished product. This aroma is certainly an aquired taste and has for decades been the trademark of Islay whisky. Well known brands like Laphroaig, Lagavulin, Caol Ila, Ardbeg and Bowmore are all more or less smoky. Of the phenols contained in peat only a small part (about one third of the original level) is transferred to the finished product and during the years of maturation the level is constantly getting lower due to evaporation and oxidization.
To log your visit you have to email me the answers to these questions and wait for confirmation:
1 – Examine the top layer of the peat (the living part). The main constituent of that layer is...
A. Sphagnum moss, B. Salt grass or C. Heather
2 – At the coordinates you can see a well defined wall where peat is being cut. What is the approximate length of this wall in feet or meters?
3 – Using the growth rate stated above, approximately how many years does the mentioned vertical cut represent? Please also give the height of the wall, measured or estimated.
Should you take a picture of yourself or any other ”interesting things”, please post it as well. Always a pleasure to see who you are!
Send your answers to the cache owner and wait for an OK before you log your visit, please.
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