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Kilning

To make malt whisky you have to trick barley in to growing then halt the process with heat. And whisky lovers know that to make peated whisky you dry the barley with peat. But there's peat and there's peat.

One of my favourite ever tours is the hard hat tour at Buffalo Trace, but last time I was there it all got a bit surreal. The tour was going fine until the guide started talking about how bourbon matured in oak, and the environmental conditions in Kentucky which influenced it. How was this different to Scotland, he was asked.

In a nutshell his answer was that the cask wasn't important in Scotland at all. What mattered in Scotland, he said, was peat. Each region of Scotland had a different type of peat, and that's why there are different flavoured malts in different regions.

Utter tosh, of course, but not altogether non sensical. Because while peat is not the only essential factor in the taste of Scottish malt, the regional aspect is valid. Why is Islay peated malt so sweet and Highland peated malt more resinous and sharp? Because Islay doesn't have many trees and the rootsy influence which has influenced the taste of Highland peat is absent in the equivalent peat on Islay.

In other words, regional vegetation will affect regional peat. And imagine how much variation there is between the flora and fauna of Australia when compared to Scotland, or compared to Swedish peat, which may have been soaked in the salt waters of the Baltic.

It's early days yet, but given time new distilleries may well explore this.

Not just peat, either. There are no rules as to what you can dry your barley with. Mackmyra has already used juniper twigs, used as a traditional Swedish smoking fuel. Expect more and more experimentation in the future.

Types of wood used for casks

We know that in Europe whisky must be matured in oak for a minimum of three years. And we also know that oak from Europe is different to oak from America. These differences are fundamental - a European oak tree will twist and turn as it follows the sunlight during growth, making for gnarled and stunted trees with tight grain. Oak trees in the growing regions of America have hot intense seasons when the trees shoot up, making for straight trees and wider grain. Such trees are more porous and casks made with them absorb more liquid, which in turn will affect the spirit stored in them to make whisky. Much research has been done in this area but there is plenty of scope going forward. Japanese whisky makers are working with new flavours from Japanese oak, and there will undoubtedly be experimentation elsewhere.

Some spirits makers may go further and follow the example of some American distillers who have turned to different wood types altogether for their casks, effectively opening up a whole new spirits category. Hickory and maplewood are among the wood types which have been used.

A greater understanding of maturation

It's generally held that a single malt of 10 or 12 years old would be considered of premium quality. But who said so, and on its own, what does that age really mean?

The answer is the Scottish said so, and if you ask many distillers what it means, they'll tell you it means jack squat.

An increasingly confident and vociferous number of distillers across the world argue that an age means nothing unless it is accompanied by information on size of the cask - smaller casks result in more rapid maturation - and with reference to the environmental conditions which would have affected maturation, such as local temperature, humidity and contrast in climactic extremes.

All distillers accept that up to a point spirit will improve over time in the cask. It's just that they believe that the longer time of 15 or 18 years in Scotland might be as little as five or even three years in some territories.

They're prepared to prove it, too, pitching their whiskies against older ones in blind tastings.

It's an area of controversy - but watch this space!