The enigma of triple distillation

What is triple distillation, and how do you do it? Instead of the usual double distillation which pertains to almost all malt whisky on the planet, some distilleries distill three times. Traditionally, many (not all) Irish whiskies are triple-distilled. In Scotland, it happens occasionally in some distilleries. Historically, triple distillation was slightly more common in Scotland back in the nineteenth century than it is today, although most distilleries which did not double-distill probably used modified forms of distillation somewhere mid-way between double and triple distillation. Some distilleries will offer special whiskies that have been triple distilled, but only Auchentoshan exclusively practises triple distillation as their mode of production. Springbank uses it for their unpeated Hazelburn. Benromach, Bruichladdich and BenRiach are examples of distilleries which have churned out small batch-whiskies which have been triple distilled. Rosebank used to be triple distilled, and its new owners have said that they will indeed be practising triple distillation once the distillery is fully resurrected and on stream. Some distilleries from other countries also do triple distillations, either as the standard method or, more frequently, as part of the production; Brothers (the U.S.), Shene (Australia) and Zuidam (the Netherlands) are examples. However, on the whole, triple distillation is the province of Irish distilleries.

One, two, THREE stills at Teeling distillery in Dublin.

However, the actual practise of triple distillation is something of an enigma. Let’s start off with briefly looking at double distillation, so we know where we are.

The ”norm”: double distillation

In double distillation, the mode of production is relatively straightforward. This is what happens: wash goes in to the wash still. In that distillation, no cuts are made; the wash is simply distilled until the liquid coming off the still only holds about 1% of alcohol. The result is low wines, at an alcoholic strength of about 20–25% ABV. The remains in the wash still, which in volume is much bigger than the amount of low wines, is called pot ale. In the second distillation, the low wines (and foreshots and feints from earlier spirit still distillations) are distilled in the spirit still. Here, the spirit is divided into three separate parts. First come the foreshots or the head, which are high in alcohol but also have other quite toxic substances in them. At a specific point depending on the distillery’s recipe (and not merely on whether or not the liquid is unfit for consumption, as some people tend to claim), a ”cut” in the spirit is made. This moment is when one speaks of going ”on spirit”. Some distilleries will make this cut early in the run, while others will make it much later; it’s all about what style of whisky one wishes to produce. Basically, the earlier you go on spirit, the more floral and fruity notes will be in your new make.

We are now collecting the middle cut, or the heart of the run: that segment of the distillation which is collected as new make and put into casks. Again at a specific point depending on the distillery’s recipe, a second cut is made, and we go off spirit and into feints, or aftershots, or the tail. Very roughly, one can say that the later this cut is made, the more your new make will also contain heavy compounds such as phenols (if you’re doing peated whisky), sulphury and oily notes. Given this information, you will not be surprised to learn that Lagavulin cuts from heart to feints at a later stage than Glengoyne, or indeed even Caol ila. Anyway, the foreshots and feints, often collectively and confusingly called feints, are pumped either into a separate feints receiver, or more usually a low wines and feints receiver, to be used for the next distillation in the spirit still. The remains in the spirit still are called spent lees. The new make – the middle cut – is different in alcoholic strength depending on the distillery’s cut point, but will normally be around 70–72% before it is (usually) diluted to 63,5% and put into casks.

Thus far, for a vocabulary of distillation, we have things like wash still, spirit still, wash, low wines, foreshots (heads), feints (tail, aftershots), pot ale, spent lees, cut, new make, the middle cut, the heart. For anyone who has done a little reading about whisky, most of these words will be familiar. Brace yourselves, for we are now entering the world of triple distillation, and a whole new language of distilling. Feints still, strong feints, weak feints, high wines and intermediate still will be popping up in what is to come.

Scotch and triple distilled: Springbank’s Hazelburn whiskies are distilled three times.

With triple distillation, the actual practise of distillation is, to a layman like me at least, harder to grasp. It all depends on what happens in the second of three stills, most often called the intermediate still. Sometimes, however, it’s called the low wines still. That term is to be avoided like the plague, in my opinion. Why? Well, some use it for describing the wash still (since it produces low wines), while some use it for the spirit still (since what is distilled there is low wines), and again, it’s sometimes used for the intermediate still in triple distillation (since what is distilled there is low wines). Unusually and at times, it will also be called the feints still, when triple distillation is on the agenda. Let’s just go with intermediate still, shall we?

There seems to be at least four different methods to triple distill. All four ways of distilling would technically all be counted as triple distillation, with a possible question mark for the fourth account. I am, in advance, truly sorry about the wild confusion I just might now be incurring into your heads and hearts in the coming paragraphs.

Triple distillation, version 1: two cuts in the intermediate still

Wash still distillation: the same as in double distillation. Intermediate still distillation: the same as spirit still distillation in double distillation. The resulting middle cut is now, however, not called the middle cut, but high wines (as in opposed to low wines). Spirit still distillation: the same as in spirit still distillation in double distillation, with your three parts – foreshots, the middle cut, and aftershots. Confusingly, because we are now triple distilling which means that the alcohol level is much higher than in double distillation, the discarded parts of the spirit run will now, according to some but not all, be called ”strong feints” (a paradox if ever there was one) and ”weak feints” (of course they would be weak, that’s why they were called feints in the first place). I suppose that in the intermediate still, the low wines from the wash still is distilled together with strong and weak feints from the spirit still. By other accounts, the terms strong and weak feints are instead used to denote the discarded part of the distillation run in the intermediate still.

In this version of triple distillation, the final still is filled only with the heart of the run – the high wines – from the intermediate still. This is said to be practised, among other places, at Peter Bignell’s highly original distillery Belgrove, which produces triple-distilled rye whiskey. (Or, to confuse matters further, maybe the final distillation in the spirit still at Belgrove is done as a blank run? Keep reading…)

One, two, THREE stills at Auchentoshan distillery.

With Auchentoshan, wide cuts are made in the intermediate still and the part of the low wines which have been distilled and discarded (the strong feints and weak feints?) are then re-distilled in the same still. (See here.)

Triple distillation, version 2: no cut in the intermediate still

This is what happens at Springbank distillery, when they are producing their unpeated, triple-distilled Hazzelburn. Here, the practise is quite different, as David Cover explains in this well-written piece. Wash still distillation: normal. Intermediate still distillation: practised as what is called a blank run, i.e. a run in which no cuts are made. The result is high wines, naturally with a higher alcoholic content than low wines. Presumably, also the foreshots and feints (would that be ”strong feints” and ”weak feints”, then? Well, probably not…) from the spirit still are also used for distillation in the intermediate still. Spirit still: same as spirit still distillation in normal double distillation. (It might be added that Springbank uses way wider cut points for Hazelburn than Auchentoshan, which has extremely narrow cut points.)

Triple distillation, version 3: one cut in the intermediate still

In an article explaining triple distillation at the scotchwhisky.com website, ”The Whisky Professor” lays down the law about many a thing. While often eye-opening even to such a hardened anorak as myself, with triple distillation, we now encounter yet another description of how this is done.

Wash still distillation: normal. Intermediate still distillation: the distillate is here said to be

split into two parts: strong and weak (those feints). The latter will be mixed with the next lot of low wines and redistilled in the intermediate still.

That would mean that there is one cut made in the intermediate distillation. It would seem, in this way of practising triple distillation, that there is no distinction between strong feints and high wines. The strong feints (same as high wines?) are then said to be moved to the spirit still, where distillation is practised just as in normal double distillation, with your cuts between heads, the heart, and the tails.

Fairly comprehensible, I must say. Cudos to the Professor for explaining things well.

So, with these first three versions of triple distillation, we have three different ways to go about distilling in the intermediate still: two cuts (version 1), no cut (version 2), and one cut (version 3). Enter the expert, and the confusion rises to unprecedented levels.

Triple distillation, version 4: one cut in the wash still, one cut in the intermediate still

Of all accounts of how triple distillation is practised, alarmingly, the most bewildering one comes from the most authoritative source of all, Denis A. Nicol. In a technical anthology on whisky production, this is how Nicol describes triple distillation:

In principle, there is a wash still from which two fractions are derived – strong low wines and weak low wines – and are separately collected. A second still, the low wines still [intermediate still], is charged with the weak low wines. From this low wines still, two fractions are similarly collected: strong feints and weak feints (tails). The strong feints are presented to the third still, the spirit still, and the weak feints are redistilled in the low wines still [intermediate still].

I have so many questions here. What happens to what Nicol refers to as the strong low wines – do they go straight from the wash still to the spirit still? If so, that would mean we’re not really doing triple distillation, since a portion of the new make would be double-distilled. And what’s this with a cut being made already in the wash still? As with the Professor’s explanation at scotchwhisky.com, the distillation in the intermediate still is said to be done with one, not two, cuts. In the final still, I suppose we would still be talking about heads and tails and the heart of the run/the middle cut. (Incidentally, the practise of making a cut already in the wash still distillation is known to have been practised in Ireland already in the 1800s in what Teemu Strengell calls ”modified double distillation”: ”In [the] early 1800’s a common method in Ireland was to divide the product of the wash distillation into strong and weak low wines and then distill them separatedly into new spirits feints and then re-using the feints from both low wine distillations in the next weak low wines distillation.” Whoa, I’m getting more lost by the minute now…)

All four methods described above, with a question mark for the fourth and most authoritative version, qualify as triple distillation. Clearly, there is no absolute rule as to how triple distillation ”must” be carried out. Still, the four different techniques would mean that the liquid to be distilled* in the final spirit still would be different things – the heart of the run (high wines/strong feints?) from an intermediate distillation run, high wines resulting from no cut in the intermediate still, high wines resulting from one cut in the intermediate still, or ”strong feints” and strong low wines, possibly taken from the wash still straight to the spirit still…? (* You want to impress people with even more snobbish words just to show off? Don’t say ”the liquid to be distilled”. Use the word ”distilland”. In the wash still in normal double distillation, wash is the distilland, low wines the distillate; in the spirit still the distilland is low wines and foreshots and feints, and every drop of spirit, including the head and the tails, are the distillate.)

A final word, after all these words. Don’t say that a given whisky, or worse, ”Irish whiskey” in general, tastes like it’s triple distilled. Not only does there seem to be at least four different ways of triple-distilling – the differences between cut points, fermentation times, cask regimes and overall flavour profile ensure that the differences between different triple-distilled whiskies are massive. After all, in the world of Scotch, we have both Auchentoshan and Hazelburn – two wildly different whiskies. When the first distillery comes off spirit at 80% ABV, at Springbank they haven’t even come on spirit for Hazelburn. Have you ever heard someone nose a glass of Macallan 18 YO and say ”this certainly has the nose of a double-distilled whisky”? No? Well, there you have it.

And thus, my dear readers, endeth the lesson.

Sources

Cover, David,”Let’s talk partial triple distillation: your guide to Springbank, Mortlach & Benrinnes”, August 14, 2017.
Malt whisky yearbook, several editions.
Nicol, Denis A., ”Batch distillation”, in Inge Russell and Graham Stewart (eds.) Whisky: Technology, production and marketing, 2 ed. (Oxford: Academic Press, 2014), pp. 155–178 (quote from p. 173).
Strengell, Teemu, ”Triple distillation in Scotland”, March 18, 2012.
The Whisky Professor (alias), ”Does triple distillation make smooth whisky?”, March 23, 2016.

*

The first version of this text was a question I wanted to ask in the Facebook group Malt maniacs & friends. As you can see, it kind of got out of hand.