The Peat Essays: Part Two

Peat started out as a fuel source intended for drying germinated barley. Although, it would also originally have been used as a heat source for distilling. Deeper cuts of peat tended to be used as they burned hotter and thus dried the barley more efficiently. This also resulted in a different phenolic signature in the kilned malt. Today, peat has transitioned to the role of flavouring ingredient. Top layer peat is deliberately used as it burns cooler with more smoke, the barley is kept wetter for longer in order for more phenolic compounds to adhere to the husks and elevate the final parts per million. Today’s Octomore would not be feasible without the very deliberate and technical capabilities of modern commercial maltsters. 

The origins of this transition lie in the rise of the blending industry and the global commercial growth of Scotch Whisky. This led blenders and distillers to contend with commercial trends and popular tastes. It also led the successful blenders to purchase multiple distilleries thereby controlling the means, and method, of malt whisky’s production. This centralising of control saw malt whisky change steadily to the tune of a thousand commercial decisions. The reality of peat flavour was considered and, in time, consciously engaged with and altered. By the dawn of the 20th century it was widespread practice for a mix of peat, coke and coal - in particular anthracite, the purest type of coal - to be burned. This was to improve drying but also to control aspects of character and consistency of that character. Drying solely with hot air was also practiced by this time - a deliberate eschewing of peat entirely from the process. 

When Masataka Taketsuru was studying Scotch Whisky production at Hazelburn Distillery in Campbeltown in 1920 he noted: 

“At Hazelburn, instead of coke they use a mixture of Welsh smokeless coal and peat. Scotland is famous for producing coal but it cannot produce coal with the special qualities of Welsh coal. Not only is Welsh coal smokeless, it is said to imbue the malt with its characteristic whisky aroma. As I deepen my research into the details of raw materials and manufacturing process, my thinking has come increasingly to the conclusion that it will be extremely difficult to replicate Scotch whisky in Japan, where we are unable to produce peat or Welsh coal.” * 

The observations are speculative to a degree and raise many fascinating questions about the role of coal in flavour creation. However, most importantly, it goes to show that serious consideration was lent by this point to the role of peat versus other types of fuel material in the malting process, given their eventual impact on spirit character. This is the same world that Aenas MacDonald made effort to illuminate, one where economic necessity and quality of character are still deeply enmeshed – and peat binds both. 

In the aftermath of the Second World War, the popularity of Scotch Whisky boomed around the globe. The drive to create more whisky, more efficiently and more consistently, drove the phenomena of modernisation in Scotch Whisky. The move from direct coal fired stills to internal steam heating, the shift from worm tubs to shell condensers, new generations of increasingly robust commercial distilling yeasts – all these implemented changes were made in pursuit of better alcohol yields per tonne of barley. Similarly, wider influences such as the shift in brewing trends towards the newly popular lagers all contributed to significant changes which would lead to fundamental alterations in Scotch Whisky’s character. Within this shift also occurred one of the most profound changes: the widespread and rapid decommissioning of distillery floor maltings and centralisation of the malting industry. The result was a distinct uncoupling from one of its most foundational ingredients, the minimising of peat’s economic necessity, and its transition to becoming a more controllable characteristic.  

Between the end of WWII and the mid-1970s the vast majority of distillery floor maltings closed. This meant that the unique traits and practices of individual distillery workforces were removed from this crucial part of the production process. It also meant a vast reduction in the diversity of different peat locations being used for making Scotch Whisky. By the 1980s only a handful of peat bogs throughout Scotland were supplying Scotch Whisky production. The cumulative effect of such centralisations, modernisations, and narrowing of influences was homogenisation of character.

The composition of peat varies subtly from location to location; these nuances of variation can lead to differing flavour characteristics from different peat bogs when used in Scotch Whisky production. Peatland scientist Michael Billett, who wrote a book about the story of peat and whisky, has this to say on their natural differentiation: 

“The dominant group of plants in Scotland’s peat mosses are the Sphagnum species. They are considered "ecosystem engineers” that create, and maintain, the right conditions of wetness and acidity to flourish. Moor grasses (like bog cotton) and sedges are common throughout our peatlands, as are various woody shrubs. These include cranberry, crowberry and particularly heather, that is more prevalent in the drier bogs of the east and the Orkney Islands. 

“The vegetation that grows in a specific location is largely controlled by the dominant source of the bog's water. At the simplest level we have "rain-fed" bogs that derive their moisture primarily from precipitation. This produces a more acidic environment in which acid-loving plants flourish. The other major group of bogs are “groundwater-fed”, deriving their nutrients from deeper freshwater springs, hillside streams or in some places, seawater. These are less acidic, more nutrient-rich and floristically diverse, with a community of plants that reflect these enriched water sources. Add geology, topography, altitude and climate into the mix, and you will a range of factors that combine to create peatland areas or specific bogs with their own individual character.” *  

Locational differentiation has also been demonstrated by research papers such as the one by Barry Harrison for the Scotch Whisky Research Institute*. The most palpable evidence, though, is in the glass: Orkney peat tastes different from Islay peat; Machrihanish peat different from Pitsligo peat. Differences discernible even at new make spirit stage. 

It’s also the case that peat from certain locations was valued as a commodity in Scotch Whisky production: highland distilleries in Aberdeenshire and Inverness-shire commonly purchased peat from the Eday Peat Company on Isle of Eday in Orkney during the 19th and early 20th centuries. This is why peat is one of the most profoundly important – often missing – pieces of the terroir conversation in Scotch Whisky. 

So, what do these historic peated whiskies taste like? From my own tasting experience, I would offer a few key observations. Firstly, peat was a more common and diversely utilised ingredient in Scotch Whisky production up until the Second World War. I have tasted malt whiskies distilled between the late 19th century and late 1930s and the flavour of peat, although stylistically variable, is almost universal in those examples. Secondly, that variability is also key: the intensity and character of the peat flavours in Scotch Whisky were far more variable pre-WWII. In my experience this remained the case up until the point at which most distillery floor maltings were de-commissioned. For example, during the transitional 1970s the peat characteristics of Ardbeg, Laphroaig, and Lagavulin were wildly variable compared to contemporary examples. 

It is also true that peat flavour was far more common and intensely present in older examples of blended Scotch Whisky. It is a common argument from an industry perspective to say old bottlings of malt whisky were so rare and ‘one-off’ that no wider truths can be reliably discerned from them. This argument is less robust against old bottles of blended scotch whisky, which tended to have a higher malt content in the recipes than today, and as such frequently provide organoleptic windows into the wider characteristics of Scottish malt whisky during these historic eras of production. They frequently reveal peat was not only inarguably a more prevalent ingredient, but also a different one in terms of how its flavours manifested. 

I would characterise the flavours derived from deeper cut peat, burned as much for heat and drying as for flavour, to be dryer, more herbal and more dominated by distinctly rooty, earthy and medicinal flavours. These are deeper, more complex and ‘darker’ flavours which come across as more vegetal on the palate. In contrast, modern peated whiskies are far sharper, purer, ashier, and smokier. Think of contemporary examples of Caol Ila, Laphroaig, Octomore, and even many mainland peated variants; many of them possess a rather lemony, citric smokiness, lots of ashes, salinity, and a more brutal medical character that goes more towards things like antiseptic and iodine. 

To experience these historic flavours is difficult and unfortunately expensive these days. The most striking examples in my experience are older bottlings of Highland Park and Laphroaig. Key examples I would cite are a distillery bottling of 10 year old Highland Park from the late 1940s and a distillery bottling of 14 year old Laphroaig from the 1940s. Not only do these represent very pure and distinctive expressions of Orkney and Islay peat respectively, they are also examples of truly complete historic styles of whisky production at two distilleries whose contemporary makes we are all very familiar with today. (Tasting notes by Serge Valentin for both bottlings can be read on Whiskyfun if you’re interested). The difference between these two whiskies, and between them and their contemporary bottlings, was some of the most striking I’ve ever encountered in many thousands of whiskies tasted spanning over a century of production.