If you’re a fan of peat and peaty whiskies and you do a bit of reading or googling on the subject, it’s not too long before you encounter the letters “ppm”. And never have three letters caused so much excitement, passion, enthusiasm…and confusion: Parts Per Million.
A lot of whisky appreciation these days revolves around comparison and relativity. Examples? We measure or define how sherried a whisky might be by comparing it to a well-known benchmark: “The Macallan Fine Oak isn’t as heavily sherried as Aberlour a’Bunadh.” Or, “If you like the smokiness of Talisker 10, you’ll probably enjoy Bowmore 12.”
Where ppm sticks its nose in and causes problems is that people use it as a yardstick for comparing smokiness and peatiness in whisky. And that in itself causes dramas, as there are plenty of people out there who still don’t appreciate that smokiness and peatiness are two different things. Yes, you can have one without the other. More on that in a moment.
The peatiness in the malted barley is measured by its phenol content – specifically by the phenols in parts per million. Most Highland/Speyside distilleries use malt that has a phenol content of 1-3ppm. Things get interesting when you start to look at the distilleries that use malt with a higher phenol content: Ardmore & Talisker both come in at around 10-14ppm; Bowmore at 20-25ppm, and the big Islay heavyweights (e.g. Lagavulin, Laphroaig, and Ardbeg) are between 35-55ppm.
Where this causes confusion or misunderstanding is that people mistakenly assume that the higher the ppm, the smokier a whisky will be. What they fail to take into account is that there are just so many other variables and parameters that impact what our nose & palate perceive as “smoky”.
A great example of this is to compare Lagavulin & Caol Ila. Both distilleries use identical malt peated to exactly the same ppm phenols, and yet one is notably smokier than the other. For the full explanation and details on why this is, you can read all about it in the feature piece here. However, for the purposes of this essay, suffice it to say that blindly focussing on the ppm will not give you the full picture.
A classic case in point is Octomore. “The world’s most heavily peated whisky” they shouted from the roof tops when it was first launched. In a world where 50-55ppm was considered the maximum, the news that Bruichladdich had peated their malt to 80ppm was met with awe, wonder, and – sadly – expectation. When people finally got the chance to taste Octomore for the first time, many initial responses carried disappointment. Not because it was a poor whisky (far from it), but it didn’t deliver the massive overkill of peat & smoke that many had expected and prepared themselves for. The reasons Octomore was tamer than many expected were down to specific production methods: Bruichladdich employs an unusually long fermentation time, resulting in a very sweet, fruity, floral wash, and they run their stills very slowly. People were expecting Ardbeg on steroids, but Octomore’s production ensured that was never going to be the case. (Of course, subsequent runs of Octomore used even higher peating levels again – up to 160ppm & supposedly higher – and so latter bottlings certainly deliver a peatiness well above the original release.) As a further extension of the above, the same principles and outcomes applied when Ardbeg did their Supernova releases.
But here’s the most important bit: You also need to consider where the peat actually comes from! Laphroaig and its neighbours taste the way they do because the peat on Islay is very distinctive – maritime, coastal, medicinal and seaweedy. The peats used in the Highlands & on Speyside are of a completely different chemical composition, and so – not surprisingly – they impart very different flavours.
A great example of this is the superb Benromach Peat Smoke expression. The label boasts that the malt has been peated to 67ppm and, as we just explored above, most punters would assume this would deliver something akin to a monstrous Laphroaig or Lagavulin. And if they go in with such expectations, they’ll be disappointed. Benromach is a Speyside whisky, and the peat used was sourced reasonably locally – a long way from the seaweedy, maritime bogs of Islay! As such, the dram offers virtually none of the medicinal, iodine-like notes of the Kildalton whiskies. Instead, it is an earthy peatiness, perhaps a more organic affair. It allows the floral and fruit notes of the spirit to shine (rather than be swamped by smoke) and the result is a complex and delicious whisky.
As mentioned a few paragraphs back, smokiness and peatiness are two different things, and a whisky can have one without the other. Furthermore, some phenols are discernible on the palate but not on the nose, and vice versa. The main phenol compounds in whisky and their qualities/properties are as follows:
- Phenol, which delivers the medicinal, antiseptic, and TCP characteristics
- Guaiacol, responsible for burnt / smoky notes – but discernible in taste only
- Syringol, responsible for burnt / smoky notes – but discernible in aroma only
- Cresol, which delivers the medicinal, earthy peat, organic and tar notes.
Hence, a whisky that’s very heavily peated might have a very high proportion of syringol phenols in the malt. And so hanging your hat on the high ppm level will only lead to disappointment when there isn’t much smokiness to detect on the palate.
By all means, pay attention to PPM. But don’t let it get OTT.
Cheers,
AD
PS….this little article only scratches the surface regarding peat. For a full and detailed article on the topic, check out Whisky & Wisdom’s feature article, The complete guide to peat and peated whisky.
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