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Peat in Scotch Whisky

The flavour peat bestows on a malt whisky is unrivalled, we find it to be more of an experience than a taste. The smoke seems to fill and whirl around the palate, the aroma transports us back to a B&B in the Highlands, cosied up by the fire sipping our favourite Scotch. However, the fascination of peat lies beyond just taste. Keep reading as we explore where peat comes from, it’s environmental impact and the science behind its famous smoky flavour. Our Peat in Scotch Whisky blind tasting experience explores the impact of peat in Scotch whisky with six diverse single malts. Choose a gift set or sharing box and we’ll provide a complete blind tasting experience you can enjoy from home!

In this way a wide range of phenolic compounds in the smoke end up being absorbed by the grain and, as detailed in Paul Hughes book The Science and Commerce of Whisky, different compounds impart different flavours and aromas;

  • 4-Ethylguaiacol - Smoky, meaty
  • Phenol - Carbolic
  • 2-Methylphenol (o-cresol) - Musty, Medicinal
  • 4-Vinylguaiacol - Spicy, Clove
  • Dimethylphenols (Xylenols) - Medicinal, Sweet

Crucially, the balance of phenolic compounds in the smoke depends on the composition of the peat, and this varies from place to place. Diffords Guide to Single Malt Scotch Whisky Production provides an excellent summary;

As a general rule, the longer the malted barley is exposed to peat smoke, the smokier the whisky will tend to be. The Bruichladdich Octomore 6.3 Islay Barley is the worlds peatiest malt, with a whopping 258 phenol parts per million (ppm). To put that into context, the famously peaty malt Laphroaig has a phenol level of 45ppm!

One problem is that peat is effectively a non-renewable fuel which emits a large amount of CO2 when burnt (worse even than coal when relative to the energy in produces). The bogs from which peat are cut are also important carbon sinks. The UK Centre for Hydrology and Ecology estimates that they store 3.2 billion tonnes of carbon in the UK alone.

Today, peat is no longer used as the primary fuel to dry the grain, though it is burnt specifically to infuse the grain with phenols. The use of modern drying kilns means that only a tiny fraction (perhaps 1%) of peat extracted from Scottish bogs is used in the whisky industry—the vast majority being used in horticulture and domestic fireplaces.

Nevertheless, addressing peatland degradation has become part of the industry’s emerging focus on environmental sustainability. Thus, in addition to peatland restoration, the Scottish Whisky Association, the Scottish government and the Green Investment Bank have begun to work together to reduce carbon emissions and promote a greener industry; focussing on water efficiency, green energy, recyclable packaging and reaching a ‘0% waste to landfill’ target.

In the next article of our Exploring Whisky blog series we look at the process of milling, and the infamous Porteus Malt Mill, that worked so well, the company eventually went out of business!

Further Reading;

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