Maturation away from mother distillery: Does it make a difference to flavour?

Can you really taste where your Scotch whisky is matured? Two of our whisky lecturers, Vic Cameron and Dr Gordon Steele, discuss whether maturation away from the mother distillery impacts the flavour of the final product you drink.

[GORDON] Most maturation as you know is takes place in large maturation facilities in central Scotland.

[VIC] Yeah.

[GORDON] However, some distilleries still have maturation beside the distillery and there's quite a debate about whether whether the distillery is the true distillery flavour or whether it's from the maturation complexes. What's your opinion?

[VIC] Well my opinion, from experience - because my experience is working for a company it has very large central sites - and with Scotland being such a small country, I would say where you mature it does not make a blind bit of difference. Doesn't impact the spirit whatsoever. But, I think I'm on the extreme fringe of that opinion! I think whether you mature it in the Highlands at height, or you mature it on Speyside, or you mature in large central sites in Scotland... I don't think it makes a difference. I think it's the wood that really impacts the difference but, other people have differences of opinion. For me, my experience, I don't think it plays a role where you do your maturation, as long as it's in Scotland, of course, for the legal purposes, I don't think it makes a difference. Whether it's good, whether I like it, whether it's great for the industry... that's a different question. But in terms of producing that final whisky... don't think it's important.

[GORDON] I disagree with you to a certain degree here. Why is Scotch whisky made in Scotland? I mean it sounds like a daft question. One of the reasons is because the weather that we have, the temperature profiles that we have are conducive for that flavour profile that comes out of out of the wood. If we were in Kentucky, we wouldn't. We're using the same wood

[VIC] Yeah

[GORDON] We're using similar sort of spirits... we get bourbon. Because the temperature profiles are very very different and that facilitates different reactions, different diffusion rates for different congeners coming out of the wood. And different reactions within that maturing spirit. So I would say weather and locality does make a difference, so long as you're making small amounts. As long as you have small warehouses. Because, at the end of the day, if you have a very large warehouse - warehousing complex - you are going to be blending that whisky together and the small - and it's a small difference that's going to be made - will just get blended away and you're not going to see it. The consumer isn't going to see it, it's not going to make any difference. But for small - and we're beginning to see a small resurgence of the small distilleries - you know, by small, I mean about you know half-a-million-litre-capacity type of distillery, which is very small, they have the ability to mature beside the distillery - or very close to it - and that will make a difference. Small. Not large because of the individual weather profile that they get there. For instance, I'm working with a distillery out in the Outer Hebrides, they're basically... they have cold summers and warm winters, if you like... it's very mild, it's a mild, very wet and very windy place out in the Outer Hebrides. But, not the extremes of temperature as you say, we see, in the central highlands which can freeze - it's minus 14°C and 15°C is not unknown - those hot summer days you get out on the moorlands, you know where it goes now and again... that's tremendous, that's a big thing.

[VIC] So you think those what I would maybe say slight weather differences - you know, maturation of course Scotland, Kentucky, India, huge differences - do you think those differences in relatively in different Scottish climates is enough to impact.

[GORDON] To have a subtle difference, it'll change, it changes the ingress and egress of vapours in and out of - particularly water vapor and atmosphere - in and out of out of the cask, it changes the pressure inside the cask. Changing the pressure inside of the cask will change the amount that goes into the wood and the amount that comes out of the wood because that's equally important because it's diffusion, comes comes out. I wouldn't say that you'd be able to recognise this as a central... [VIC] alright, OK

[GORDON] You know, this is matured in the central area

[VIC] This is from Fife, this is matured in the highlands

[GORDON] Exactly! Exactly because other factors will overwhelm that. You know, the quality of the new make spirit, the wood policy, how much peating is it has had in there. It comes back to what I really believe about Scotch whisky: Scotch whisky is the sum of all its parts. It's not just - and these small differences all add up to big differences - at the at the end of the day. It depends what product you're making, I think.

[VIC] Well, what I'm hearing from you is: yes it makes a difference and no it doesn't make a difference!

[GORDON] Yes, exactly! That's exactly it.

[VIC] So if you're making a huge brand and thousands and thousands of casks, yeah, put them somewhere centrally

[GORDON] Exactly.

[VIC] But one or two casks here or there

[GORDON] Precisely.

[VIC] for this individual expression, you think that could make a difference.

[GORDON] Yes. I agree with you there, it depends on the product you're making. If you're making a big volume blend, what's important is Scotland.

[VIC] Yes, anywhere in Scotland.

[GORDON] Because the weather, the average weather, because that'll be being matured, say, over 10 years or something like 12 years perhaps for some of the deluxe blends. It's important that it experiences Scottish weather. A warehouse is just to stop thieves, it doesn't stop it doesn't stop the weather! It doesn't stop the temperature, it doesn't stop the humidity... but, if you're making a malt

[VIC] Small volumes

[GORDON] small volumes, where you can put together small parcels that just come from say an individual warehouse, then you will get you will get, uh, differences but they'll be subtle.

[VIC] Some of the marketing maybe, dare I say it, you know, certain brands, they've got their warehouses below sea level and do you think that makes a difference to, you know, some of these brands?

[GORDON] Probably not

[VIC] In the volumes that we're talking about.

[GORDON] What's probably making the difference is that local weather, where that - because that's the important thing for maturation - the weather, the temperature profiles and the humidity profiles. Because that decides the diffusion rates and the reaction rates that go on within a cask. Also determines some of the loss rates as well, so you'll get differences in losses - very small amount, small amounts - and that will also affect strength within the cask.

[VIC] Aye, which affects volatility.

[GORDON] Precisely, precisely. So, over time, you will get some differences. What you don't get is, say, if you're beside the sea, you get a maritime note, taste of the sea. If you're behind beside a pine forest, it will be more piney. If you're up in the moorland, it will be more moorlandy, whatever that is

[VIC] I'm thinking of a whisky now, made by the sea, salty, yeah, but matured in Fife.

[GORDON] Exactly, exactly, we can all think of examples like that. That's down to peating levels, that's down to cuts, down to recipe, down to the skill of the distillers themselves and that accumulated knowledge.

[VIC] So, kind of going off piste here, but what do you think about palletised warehousing?

[GORDON] Palletised warehousing, your losses would go up slightly but you get more casks in!

[VIC] So you've got more losses, over less time, more casks, so kind of the monetary balance

[GORDON] The bad thing about palletised warehouses from a maturation point is you've got one of the ends

[VIC] Aye, completely dry.

[GORDON] Completely dry. And, so you've lost all that, the congeners coming out that wood.

[VIC] So I'm kind of hearing anecdotally that losses are something like two or three times more.

[GORDON] Oh, I wouldn't say, not as much as that.

[VIC] Not as much? That's just what I'm hearing.

[GORDON] I've not seen that but I mean there might be cases that I'm unaware of but I've not seen that.

[VIC] But just in certain instances.

[GORDON] Where you do get higher losses is at the top of the warehouse. We've gone, the industry has gone from sort of three-cask-high warehouses to giant three bay warehouses, you know, these massive big warehouses. And there's a big difference in the atmosphere where - if you ever go into one - they all feel quite cold, the atmosphere feels very stable but actually at the top of the warehouse it can go up and down in temperature as the sun comes in - in and out - and you're unaware of that because you never experience it. So, I would recommend that you put some insulation on the roof of a warehouse to stop that. And then you get greater losses. Do you get differences in maturation? I don't know, it's simple. We couldn't find any but then you need to look over... that's a 12/15 year experiment! Because you can't do any comparison, you have to just look up in there. So, we don't know.

[VIC] I think it's an interesting question, an interesting point because a lot of the industry is moving towards palletised. Much easier to build a big empty shed and fill than a racked warehouse and much smaller footprint than a dunnage warehouse, so it's going to be used.

[GORDON] You get greater losses and one of the reasons you get greater losses is you've got two bung holes in. Because the Bourbon guys will have always put a bung hole on the bilge. But you've got to put one on the end. So you've got and that's a major source of loss, is the bungs. You know, it might not look wet but that's where it comes from and plus you've got the croze at the top is dry. Pressure difference - which is the atmosphere - changes the pressure of the gas, the headspace within a cask. Because of the huge volume of liquid there is within a warehouse, the liquid takes a long time to change temperature. So, it lags about three days behind atmospheric temperature. So, if you have fluctuations of temperature which are shorter than a day, that just changes pressure, air pressure

[VIC] Right, okay.

[GORDON] And so that can change the maturation profile because of that. Usually ending in greater losses because of that, because it's forcing, pushing stuff out, rather than pushing stuff in. Because there's no alcohol to push it in! Or very, very little. As I say, it's an open question and one of the unknowns about how that affects flavour at the end end of the day. My gut feeling is it can't do it any good. You know, it's not going to improve it.

[VIC] Not going to improve it but is it going to be a detriment? Not sure.

[GORDON] I don't know. I don't think so. But then, once again, you're talking about giant warehouses and that's going to... the blending, the blender is going to take care of that

[VIC] And a lot of your, the ones you were talking about, where you think it might be a difference, a lot of these smaller distilleries, still going to be a little dunnage warehouse next to the site, so it's still going to be done there. A lot of volume, probably, is being palletised and some of that smaller volume might still be dunnage.

[GORDON] Yes and some companies, that's their policy. Is to is just keep racked: Macallan and Edrington spring to mind, that's their policy is to do that. Often based on on cost, looking at cost rather than maturation profile but also, they also believe that they get a better - or more consistent - product.

[VIC] And they're putting up a lot of warehouses.

[GORDON] Yes, well, everybody is.

[VIC] Yes.

[GORDON] I can see advantages and disadvantages for both. For a smaller warehouse, I personally would go for racked because you've got both ends in contact and you're just going to get more congeners coming out. Plus, more charred, uh, char in contact with the spirits. Some people will have their sherry casks racked, rather than dunnage, for that reason.

[VIC] I was at a new distillery yesterday and they're going for dunnage because they feel that's the best way to mature and it's the way they want to mature. But there's something about dunnage warehouse, isn't there?

[GORDON] Yes!

[VIC] That's just the best place in the universe, to wander about and see the casks and smell it. And there's something just un-nice about a racked or a palletised warehouse.

[GORDON] Yes, it's a bit too clinical, it's a bit too clinical. I also feel unsafe because they're about seven high now!

[VIC] Well, I used to manage the ones at Benrinnes which were eight or nine high.

[GORDON] 8 or 9? Good grief.

[VIC] And I used to hate going up the top because I didn't like heights.

[GORDON] But, also, I think that demonstrates just how a good design casks are, they can take that weight, how that double curved shape of the cask is so well designed, over time.

[VIC] But it's just a wonderful process maturation full stop, isn't it? Wherever you do it.

[GORDON] Yes. Well, that's the big change isn't it? From new make spirit, that's when you actually see the spirit appear and that's when you get very interested in it because you can actually see spirits, actually see whisky appearing at the end! Particularly if you're involved in a new recipe, or involved in a new distillery, or... that's the culmination, often, of years and years of work and investment and then you start to see it come out the other end. The excitement is just, second to none.

[VIC] And at home, I have a special shelf, where I've got about six or seven bottles from various sites, you know, that were made while I was a manager.

[GORDON] Oh right.

[VIC] So that's wonderful to have, it's just such an exciting exciting process.

[GORDON] Fantastic.

[VIC] Excellent, thank you!