What Is Peat, Anyway?

The un-poetic answer is that it’s basically decaying vegetable matter (with, perhaps, some decaying animal matter thrown in). The more poetic answer is that, when burnt, it’s the signature smell of Scotland.

The sense of smell is one of our deepest and most meaningful, and when a colleague of mine opens a bottle of Scotch, the smell takes her back to when she was staying at a pub in the Scottish hinterlands. Of course, Scotland is very far north. In the Winter, it’s dark. And wet. And cold. Perhaps the appreciation of whisky isn’t such a surprise! Anyway, in order to survive the Winter, the inhabitants needed to burn something for warmth. You guessed it: Peat. Whenever my colleague would come in from the cold, to the shelter of the pub, the first sensation would be the smell of the peat smoke. The smoke smell was always associated with protection and warmth.

So, why do some whiskies have a noted “peaty” character? I read a lot about whisky, and some folks’ tasting notes separate a “smoky” nose from a “peaty” nose. Others may refer to “heat.” I think this variance of terminology is what makes tasting in groups so much fun. You can compare notes and help each other converge on the right words for the flavors and smells you encounter.

The reason peat is burned during the production of whisky is that heat is what stops the malting process. Barley is malted by adding water and waiting until it sprouts. The sprouting process liberates the complex carbohydrate molecules in the barley, which are then available to the brewers’ or distillers’ yeast for fermentation. Actually, I am skipping over quite a few steps.

First, the barley has water added so it germinates. It’s a seed, so adding water makes it grow. At just the right point, the sprouted barley is heated to dry it. The heat stops the germination process. I’m no plant biologist, but it seems to me that the heat must kill the barley plants. The goal is to extract those valuable carbohydrates from the inside of the barley before the plant consumes them to fuel its growth. The first step of that extraction is to add more water and this is when the wee beasties are added: The yeasts! (Actually, yeast is a non-chlorophyll-bearing plant, but since yeast rhymes with beast, it’s hard to resist using the word “beastie.”)

The yeasts do their work and convert some of those carbohydrates to alcohol. It’s hard to get this solution to have more than about 15% alcohol by volume (ABV) because the alcohol that the yeast produces is toxic to the yeast. At some concentration, the alcohol will kill the yeast. So the first-level output of the fermentation process, a product very much like beer, is about 7-10% ABV, a point well below that which would kill the yeast. Then, distillation is used to increase the concentration of the alcohol. The output of the stills is called “new make” spirit.

Back to the peat: Traditionally (like perhaps 200 years ago), all whisky was made after drying the malted barley over peat fires. As the industrial revolution wore on, other fire-making technology became more common: Coal, natural gas, etc. For a variety of reasons, perhaps pragmatic, perhaps stylistic, peat-fired distilleries became rarer on the Scottish mainland. There is no reason why any Scotch today couldn’t be made using peat. As it happens, the predominant peat usage is on Islay, the small island just off the western coast of Scotland.

What would affect how peaty the final product will be? Well, some people say that the water plays a part, and it’s hard for that not to be true (it’s debatable to what extent water affects the final product). The water sources for some Islay distilleries filters through peat bogs. Water used for Highland whisky production filters through limestone. This can’t be the only (or even the dominant) factor, since there have been peated Highland and Speyside Scotchs produced. The peatiness has to come from more than just the water. Strangely, it seems that the thing that really affects the peaty aroma/flavor is the weather!

The prevailing winds bring storms across the Atlantic and hit the coast of Scotland heading in a northeasterly direction. Islay is positioned such that it bears the brunt of these storms. The distilleries on the southwest side of Islay get lots of rain. It’s moist there. Very humid. How do you think that affects the malting process? Right. It takes a longer time over the heat to stop the germination. That would account for some of the peaty texture of the whiskies like Laphroiag and Lagavulin and Ardbeg (go ahead, look at a map of Islay and confirm that they are, in fact on the weather-facing southwest corner of Islay).

I hesitate to attribute all of the peatiness to the weather. I think the most likely explanation for the peatiness of Islay malts is a combination of weather and preference. At first the peatiness may have been borne out of necessity, but I suspect that the folks on Islay grew to like their whisky this way (and so do many others; this is a boom period in the whisky business, and the broad “Scotch” category is hot — and in particular, the Islay Scotch market is incandescent). I suppose that they could make the whisky with less peat if they wanted to. But why?

Bruichladdich is in a slightly more protected cove (Loch Indail) and as such may (just a theory on my part) have more flexibility in their use of peat. Bruichladdich Islay Scotch whisky ranges from virtually unpeated to Octomore II, clocking in at 167 ppm phenols. Remember I said Port Charlotte was a bit peaty for my taste when I first had it? Well, it’s at 40 ppm. The Octomore II is fully four times as peaty as the Port Charlotte (and that’s twice as peaty as the first Octomore was). I think that the use of peat, and how many times the spirit is distilled, should not be about dogma…it should be about good results: Do consumers like the taste?

Note: When I say “dogma” I am referring to some people’s assertion that there is a regional flavor profile or distilling style that is somehow etched in stone; there is no rule that says that all Islay malts must be peatier than others; there is no rule that says that only Irish whiskies can be triple-distilled; etc. Bruichladdich’s master distiller Jim McEwan and his team are not constrained by the expectations of the market for what an Islay malt should be. They are clearly willing to take risks and do their own thing. So far, the results have been outstanding: Bruichladdich has won many awards within the industry and the market has taken notice, as they are the fastest growing brand on the market.

The next posting will be about the history of Bruichladdich, cobbled together from a variety of sources. Then I’ll get back to the important stuff (the whisky!) and start to work my way through their many expressions. I will break them down into categories to make this a bit more tractable.


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