In a nutshell peat is carbonized vegetation that’s been laid to rest for thousands and thousands of years in boggy wet ground.
Over the years the water from the bogs really soaks into the peat and it brings all the surrounding flavour into the peat itself.
Peat is then cut out of the boggy ground by the Peat Cutter (funnily enough), dried off and used as a fuel source. Peat cutting was once done by hand (and is some places still is) but now with the global success of peated whiskies modern harvesting methods are now used with the use of machinery.
Peat has also been used as a domestic fuel source for many years and still is in a few places in Scotland, but in this case, we are going to talk about peat for the drying of malt.
So to the whisky!
Peat comes into play in the kilning process at the very early stages in whisky making.
The kilning process is essentially the process of drying the malt. Traditionally this is done on a malting floor where the malt is spread out over a perforated floor with the furnace (Kiln) below. The hot air passing up through the malt evaporates any moisture.
When peat is used as the fuel source in the kiln, the smoky peat flavour and fragrant smoke is trapped in the grains which in turn impacts the flavour of the final whisky.
This fragrant smoke and peat flavours are called Phenols.
Phenols are the chemical aromatic compounds given off when peat is burnt (nerd alert!)
So with that in mind the longer the exposure to the peat smoke - the larger the flavour.
Not all distilleries make their own malt, most will buy commercially malted barley.
Each distillery will have their own recipe that they like to use for making the desired flavour.
PPM (phenolic parts per million) – Is the measurement used to determine the level of peat that is used in the peating process.
Around 50% of phenols are actually lost in the distillation process but they obviously still play a massive part in the final flavour.
Here’s a few examples:-
Highland Park 12yo sits at 20PPM
Lagavulin 16yo sits at 35PPM
Ardbeg 10YO is a whopping 55PPM
So really the higher PPM the smokier the dram!
Different types of Peat
Many distilleries and regions dropped out of using this wonderful fossil fuel over the years. However a good few kept up the trend.
Islay is known by many to be the peat capital of the whisky world.
Islay peat when burnt produces flavours of salt, brine, oyster and crab shell.
Orkney has a specifically fragrant peat – sandy heather and salt. These flavours are produced by the roaring winds and salt spray over the years. These winds and salt means there aren’t many big trees on Orkney which in turn makes the peat more aromatic/fragrant.
On the Isle of Jura (wee island next door to Islay) – the peat brings wafts of ferns, green woods and pine.
These flavours are down to the greenery on the island and results in a more woodier, dry pine flavour.
Highland Peat – it’s reekin’ of heather and a bit more earthier than your Islay or Island Peat. You really notice that burnt heather in a lot of the Ardmore whiskies specifically.
Terroir/Climate and Regionality
We can’t talk about Peat and not talk about Terroir/Climate and Regionality.
All whisky is different. Why? Well every variable plays a solid part in whisky making.
A lot of (silly) people will often categorize whiskies by their flavour and regionality as if they are the same thing. “It’s a Speyside which means it tastes real fruity.”
“Oh, have you heard about that Islay whisky? Everything from there tastes like smoke.”
I call bullshit on that one.
Yes. Terroir and climate definitely play a part in a whiskies flavour but does regionality? Not really.
Take Islay for instance since we are chatting Peat.
Islay is a tiny wee beautiful island but all the whiskies from that island have a different flavour profile.
Look at the Kildalton trio (Ardbeg, Lagavulin & Laphroaig) for instance.
All the distilleries within meters of each other and all of them taste completely different.
But why? They are all from the same island and so close together so surely, they should taste the same? Nope. Nope. Nope!
It’s not just the climate they come from. It’s the full process. From the malting, to the distillation, when the spirit is cut, when it’s rested, how it’s rested and of course the PPM. There are far too many variables for distilleries to taste the same.