When it comes to Scotch whisky, there is a great divide amongst single-malt drinkers, and that great divide is peat. 

I’ve been in the whisky biz a long time, and generally I’ve found that when it comes to peat in whisky, like Marmite, you either love it or hate it. Regardless of whether or not you’re a peated whisky fan however, it has to be said that peat has played a key role in the production of whisky over the centuries. 

Centuries ago, peat blocks were burned as fuel to provide a heat source for the pot stills. As the years ticked by however, we found alternative sources of fuel and so peat was no longer needed, not in that capacity at least. Instead, it is used to help flavour the whisky and give it its unique, smoky, earthiness. 

Here’s a quick look at the link between peat and whisky and why, for many, it’s the perfect combination. 

What is Peat?

Peat is an organic surface layer of soil that is made up of decomposed plant matter and other organic materials. There’s a lot more biology involved, but basically, peat is an accumulation of decayed plant matter, vegetation, and other organic materials that have been heavily compressed. Think of it like a compost heap that has been millions of years in the making. 

Peat is found in bogs, marshes, mires, moors, and other similar areas of the UK known as ‘Peatlands’. 

Because it burned so well, workers from the distilleries would make the trip out into the countryside and cut away slabs of peat and bring it back to the distilleries, where it would then be used to heat the stills. 

Peat in Whisky Production

As mentioned, peat was initially just used as a fuel source because it burned so well. As the centuries passed by however, alternative fuel sources were discovered. Peat was however, used in a different capacity, namely the malting of the grains. 

Malting is a process which promotes germination of the barley. This is an important step because it helps to facilitate chemical reactions taking place within each grain, converting the energy inside to prepare it for fermentation, which is when it forms ethanol (alcohol). 

Here, the barley would be spread evenly on the floor of the malthouse, which would then be heated via a kiln below. The heat promoted the germination. To heat the kiln, slabs of peat were used. Initially, the objective was purely to provide heat, it was discovered, however, that the smoke produced from the peat was absorbed by the malted grains of barley, where it imparted a rich and smoky, slightly earthy flavour that was present in the whisky. 

What Does Peat Taste Like?

Nowadays, peated whisky is incredibly popular, and has become somewhat of a trademark of whisky produced on Islay. Popular examples of peated whisky include brands such as: Ardbeg, Bowmore, Laphroaig, Talisker, and Lagavulin, to name just a few.