Peat. Heard of it? You almost certainly have if you have any interest in whisky (or gardening, or the environment for that matter). Peaty whiskies are perhaps the most polarising topic in whisky. Many people fall into a category of either seriously disliking it or becoming a full-blown enthusiast (a peat-head or peat-freak if you will). Whilst peaty whisky is a hallmark of Scotland’s whisky scene, it can be found in varying quantities in other regions, with Ireland in particular increasing its presence in recent years. But how much do you know about one of the most interesting, and controversial, components of the Scottish whisky industry? What is it? Why is it so synonymous with whisky, particularly in Scotland? And why might its future be murky?
Let’s start at the beginning. Peat is the end product of vegetation that has only partly decomposed in acidic and anaerobic conditions, and the bogs and wetland areas of north and west Scotland fit that bill perfectly. The plants grow and die, fall into the soil and go through the partial decomposition process to eventually (over thousands of years) form peat. Peat is not far removed from fossil fuels like coal and oil but then this is where its long-term usefulness for humans stems from. For centuries, humans have used the peat bogs to survive, live and thrive. When peat is cut out of the bog and allowed to dry, it makes an excellent fuel source. This was particularly important for areas that were without much wood (trees and bogs are not always good bedfellows) as it allowed early people a way of heating their homes or cooking their food. Over time, this process of cutting, drying and burning peat worked its way into making whisky.
Because it was a valuable fuel source, peat was used as part of the malt production process to dry (kiln) malt in areas like Islay, Orkney and the Highland coasts where it was ubiquitous. But not only could it dry the malt, it also imparted a strong flavour that would pass through into the end spirit. And so, peat was used for a large section of early Scotch whisky production across many regions and distilleries, and a distinct, unique and admired flavour style was created. The use of peat is rather fleeting when you look at the entire whisky process, yet its impact is almost unmatched. The peat is burnt so the smoke can be passed across the wet barley while in the kilning stage. And that’s it. At no subsequent point does peat reappear in the process. Depending on how wet the barley is, the amount of compounds in the peat smoke that stick to the malt can vary. Distillers can play around with those parameters (as well as length of exposure) to get their desired peaty hit for the final whisky. We measure the impact of peat in phenols and use a parts per million (ppm) scale. Somewhere between 1 and 10 ppm will indicate a lightly peated whisky, while the hard hitters at the top of the chain (like Bruichladdich’s Octomore) can be above 80ppm. Most of the well-renowned peaty whiskies (Laphroaig, Ardbeg, Lagavulin) are somewhere between 30-50 ppm and that seems to be the sweet spot for the general peat whisky drinking public.
The impact of peat on whisky is noticeable, and impactful. There’s not 1 exact descriptor for peat, instead there are many. Smokey, briny, seaweedy, like creosote, medicinal, perhaps even burnt. Some researchers estimate that peat can provide over 80 different aromas depending on different circumstances. I remember my first experience of a peaty whisky was getting a whiff of an unknown whisky and my first thought being of TCP, or disinfectant (for those in the know, it was a Laphroaig). But even for the most novice whisky drinker, a peaty whisky stands out from the crowd. It’s that distinguished and characteristic hit that makes it so adored (or so hated) by large swatches of the public and of experts. There’s no missing a big-hitting peat whisky, and sometimes there’s nothing better. I’m not the biggest peat fan yet, but on a cold night, or if I’m by a fire, or to finish off a night of drams, it’s hard to beat a big, punchy peaty half.
Because peat is a bit of a catch all term for partially decayed vegetation, you can get differing styles and flavours depending on where the peat is from. Islay peat is quite different to that of the Highlands, which is different again to Orkney. This can give each whisky using a different peat a different flavour profile. Like the soil type can impact a wine, providing a unique ‘terroir’, so a peat’s source can influence a whisky. Of course, other factors play a role in the final product quality, and some will argue that the source of the peat matters little, but perhaps that minor tweak to a profile can make all the difference.
But much like everything, there’s a twist with peat. As we noted in our look at what peat is, it takes a long time for it to form naturally, and it should be considered an unrenewable energy source like its fellow fossil fuels. Peat bogs and wetlands are also some of the most important ecosystems in places like Scotland, Ireland and central Scandinavia for wildlife and plant life, and also as a tremendous carbon sink. In fact, even though they cover a relatively small percentage of land across the world, it is estimated that peatbogs contain twice the amount of carbon than all the forests. Simply put, the continued use of the resource is not exactly ideal in any context. It’s not just its removal to consider. The burning of peat releases substantial amounts of carbon into the environment.
While whisky might be amongst the most well-known uses of peat in the UK, it’s not closest to the biggest consumer. That would be horticultural compost which could use up to three million cubic metres of peat every year, a third of which is sourced from peat bogs across the UK. Whisky production might use than 1% of all the peat consumed in the UK in any year, but with sustainability at the forefront of the industry’s mind, work needs to be done urgently to address the peat situation.
What are the options? Well, the easy one is to not use it all. Many newer distilleries just avoid it altogether and go for an unpeated whisky. Instead of peat, they’ll rely on heated air currents to kiln the malt. That’s fine for them, but not all distilleries will want to go down that route, especially the ones with a well-developed peaty style and brand.
How about alternatives? If you want your whisky to have a smoky hit, that’s (somewhat) easy. You can use a different fuel source. Some use various types of wood but others go outside the box. In many other countries, they would use a fuel source that has historically been used for cooking food. In Denmark, using beechwood is a firm favourite for meat and now whisky, but Fary Lochan utilises nettles for a special whisky. In New Zealand, Thomson Whisky use manuka (yes, the same plant as the honey). And in both Iceland and Australia, distilleries turn to sheep poo after it is collected from farms and dried. Yes, you read that correct. If it burns and doesn’t ruin the taste (and I’m led to believe that sheep poo does not), it could be coming to a smoky whisky near you soon. But what if you want that authentic peat hit? Then it’s more complicated as there is no direct replacement yet.
The Scottish Government is often forward thinking (not always correctly though) when it comes to the environment and nature. It has a difficult balance to strike because sometimes, the focus on the environment can directly conflict with the economy and livelihoods. Some form of peat use regulation looks like it might be on the horizon given there’s a significant Government commitment to restore peatland, but how far might it go? A blanket ban would appear to be several steps too far and would enrage both the whisky and horticulture industries. Perhaps then it’s going to be about limiting or restricting its use. That feels more likely and while it might not be imminent, whisky producers will be keenly aware it might be on the horizon. The Scotch Whisky Association produced “The Commitment to Responsible Peat Use” in 2023 to outline its ambition to restore peatlands, maximise and optimise the use of peat and reshape best practices for peat removal. Perhaps these assurances will be enough to keep the use of peat ticking over without the need for a full ban or a prohibitive restriction. By working with scientists, nature boards and bodies and local groups proactively, there will be viable options for how to both protect peat sources without eliminating the use of peat in whisky. It might not happen overnight, but it’s positive to see the work starting in earnest.
So while peat remains a controversial subject which will continue to garner attention for the Scottish whisky industry, its use is not going anywhere. That doesn’t mean that other, novel sources of that often much-loved smoky aroma and flavour won’t be researched and utilised in both Scotland and across the world. In Scotland, expect many distilleries to continue their investment into protecting and restoring the native peat bogs while the industry, the government and nature NGOs work out the best path forward that works for all parties. For now, you can still get your peaty whiskies from Islay and the Highlands, but why not search out the others trying new techniques. Who knows, maybe you’ll become a sheep poo whisky enthusiast.
Sean black - Freelance writer 