The Science of Whisky

[Wub]

I don't know about others, but when I get interested in a topic (as I am about whisky at the moment) I like to learn as much about it as I can. One thing that interests me particularly at the moment is the science behind the flavours that we find in whisky. Some people will think that it doesn't matter what produces the flavours and will enjoy them for what they are. That's fine, but I think there must be others who find this topic interesting. Rather than distract form the pleasure of drinking whisky, I think a bit of knowledge adds another dimension to it

So this thread is meant for those with a similar bent (if there are any). I thought I'd start by mentioning some aspects of production which (from my limited research) may have an effect on the aromas and flavours of whisky.

Water source
Distileries are fond of expounding upon the source of their water, but how much does this really affect flavour? The water may travel through peat, but does that water taste peaty? If it doesn't taste peaty can it really be said to contribute a peaty flavour to whisky? Ive read about hard and soft water (hard water being that which has a higher mineral content), but at the moment I'm not aware of how this might affect the flavour profiles of whiskies.

Peat
Obviously there's a noticeable difference between peated and unpeated whisky, but before we even get to the drying stage there's he question of the source of the peat, and the layer of the peat used. How much do these things really have of on the character of the whisky?

Fermentation, Barley and Yeast Strains
Frementation produces many of the compounds that we later taste in our whisky. Do the strains of barley and yeast used have a noticeable effect on flavour? (Macallan seem to think the barley strain is important).

Distillation
There are probably too many variables here to note under one heading (but I intend to go to bed at some stage): the size and shape of the stills, temeratures, timing and so on. And distillation, as a refining process, is going to have an effect on the compounds produced in the earlier stages.

The Cuts
Where to switch from foreshots, to heads, to feints? Each distillery has it's own formula, and this has to have a huge impact on the relative levels of compounds that end up in the spirit.

Maturation - the Wood
Since this is probably one of the most studied, and most understood aspects of whisky production and it's effect on flavours and aromas, I find it the least interesting. One thing that I did find interesting, and hadn't thought of before, was that the charred wood can produce many of the phenols that we usually associate with peat (which seems obvious in retrospect) - so that if you get a hint of peat or smoke from a whisky that's produced from unpeated malt, that's probably the cause.

Maturation - the Location
This still seems to be a matter of debate: can the location of storage during maturation really impart a maritime flavour to the whisky? My guess is no, until I see a scientific explanation of how the relevant compounds (whatever they may be) are infused into the spirit. Still, it's a romantic idea.

Bottling - Chill-filtering and Caramel
It's getting late, so I'll summarize quickly: chill-filtering removes some compounds that may cause whisky to go cloudy when diluted or chilled, but those compounds may have had an effect on the flavour. Caramel is often added to whisky to adjust the colour, but perhaps the caramel can be tasted.

OK, time to go.

Mark

[Deactivated Member]

Oh, oodles to talk about here--in fact, there have been dozens and dozens of threads here on the many topics you touch on. There's a lot I'd like to comment on, but I'll start with this: barrel char actually seems to absorb unwanted flavors, making the whisky smoother. You've never had a smoky bourbon, have you?

[Deactivated Member]

A couple of other points:

Peaty whisky from peaty water is a myth.

Peat from different sources definitely has differing characters. For one thing, peat is not a monocultural plant--there's lots of stuff in there, and it will vary from place to place. Read the Peat chapter in Jefford's Peat Smoke and Spirit. Distilleries that do a portion of their own malting--notably Laphroaig, Bowmore, and Highland Park--may take their peat from very specific locations.

I think yeast plays a bigger part than most people realize. Different strains produce different chemistries.

I've been struck in my reading by the fact that different distilleries have vastly different fermentation times. Some like slow, some fast.

Location is important in that temperature and humidity, and the variability thereof, are important. The infusion of salty air and seaweed into the whisky is another myth.

[Wub]

in fact, there have been dozens and dozens of threads here on the many topics you touch on.

I figured so, but it would have been silly to ressurrect dozens of old threads just to add my 2 cents worth.

You've never had a smoky bourbon, have you?

I think the only bourbon I've ever had is Jim Beam, and that would have been with Coke. I don't think I remember smoke, unless it was the one in my mouth.

[corbuso]

If you are interested in the science of whisky, have a look at the book of Hume (Making of whisky, http://www.whisky-news.com/En/literature1.html)
and the two other books on whisky technology (http://www.whisky-news.com/En/literature.html) and you might find some other related articles I wrote here: http://www.whisky-news.com/En/whiskyExp.html

Corbuso

[Wub]

I've been struck in my reading by the fact that different distilleries have vastly different fermentation times. Some like slow, some fast.

There are so many variables at all stages of the process that it's almost surprising that all distilleries produce something that we still recognize as whisky (I haven't sampled enough to say whether that's strictly true).

So in the end the biggest influence on flavour must be the fact that all (malt) whisky is produced from malted barley. Uh...OK, got that cleared up.

Thanks for the links Corbuso. I'd already found your article on peat, though I haven't read it yet.

[bankerjoe]

I am definitely this type of person. I love science. I love understanding how and why things are the way they are (philosophy is another love). I like digging, and learning.

Everything mentioned, I would love to read or study about further.

I guess I am a nerd.

[Pure Pot Head]

I have heard a number of Distillers dismiss the influence of water source at the pre wash stage. There are so many processes that are required now to treat water to comply with health and safety regulations etc. Maybe in the past when distilleries were run on a much more haphazard style it was a factor. And maybe for the worse!

There is an old story about the original Jameson distillery in Dublin. Around and under the distillery is a peat layer that the water souce use to produce the wash filtered through. There is a church right next to the distillery that was visited by Alfred Barnard in his big tour of Distilleries in Britain and Ireland where he came across some incredibly well preserved bodies in the crypts dating way back. They are stlll there over a hundred years later still preserved and you can still view them.

Not sure what the scientific effect was on the whiskey though! But needless to say the legend was that this was the reason for the whiskies life enhancing properties!

[Deactivated Member]

Well, bodies don't decompose much in peat bogs...there was that 900-year-old lad they found in Caithness a few years back. But it's not because peat is life-enhancing, in fact quite the contrary--bogs are so acidic that none of the organisms that normally break down organic matter can live in them. And that in fact is why peat is a good fuel.

[Wub]

A distinct note of body on the nose, refining to Late Bronze Age at the rear of the palate. The finish is long and delightfully pungent, leather, smoked kidney.

[Pure Pot Head]

But it's not because peat is life-enhancing, in fact quite the contrary

Mr Tattieheid, you're ruining a good Dublin story!

Pure Pot Head

[Pure Pot Head]

Here's that little passage from Alfred Barnards book all the same!

[cathach]

Thats St. Michans isn't it? There's a chalk layer around the crypt supposedly that keeps everything so dry that it doesn't decompose. I've seen video footage of the interior and there's even one 'Crusader' body that people would go in and shake the hand of for a blessing.

There's a similar phenomenon in St. Audeon's Church, but they don't let you in the crypt anymore due to toxic gases from the Liffey or an aquifer underneath.

[Pure Pot Head]

It is st Michan's. I've passed it on a number of occasions on visits with friends to the Old Jameson Distillery but I've never gone in. Something on my to do list!

Pure Pot Head