If there is one persistent meme that seems to have firmly inserted itself into the minds of everyone with even a passing awareness of scotch-style whiskies, it is that single malts are of perceived higher quality than “blends”.

Many will certainly agree that the greatest diversity of flavour comes the traditional, single pot-distilled, malted barley form of whisky, aged for extended periods in oak barrels (aka, the classic Scottish single malt). So it may therefore surprise you to learn that almost all “single malt” scotch you will find in your local liquor store is in fact a blend of many different individual whiskies.

Blending vs Vatting

This is our first lesson in how the marketing machine that barrels over (pun intended) the whisky world has distorted people’s understanding of this product. In an effort to provide a cachet (and justify a higher price), single malt whisky has undergone several decades of extensive “higher quality” branding. Most people naturally assume that “single malt” means just that – a single whisky from a single barrel. In fact, what a Scottish “single malt” actually means is that it is only malt whisky, prepared in the traditional way, and produced by a single distillery in Scotland. Note the distinctions inherent in that qualification.

In fact, pretty much every “single malt” you can buy (aside from some limited individual cask expressions) is produced by “vatting” or “marrying” together dozens to hundreds of individual barrels of whisky. Of course, those are just fancy ways of saying blending. 😉 Maker don’t like using the word blending in this context, since a “blend” is the short-form name for a specific combination of different styles of whiskies (as I will explain below).

Typically, the individual malt whiskies that get “vatted” together have been aged for varying amounts of time, in barrels that previously contained different types of spirits to start with (see my discussion here of where whisky flavours come from).

Age Statements

Wait a minute, I hear you ask – so what does that age statement (e.g., “12 year old”) mean on my bottle of single malt? It certifies the minimum age of the youngest whisky that went into that vatting. So your bottle could contain only a miniscule amount of 12 year old whisky, and be heavily biased toward much older whiskies. And technically, ALL the whisky in there could be well over 12 years old for that matter. See this post for a good example of just such a case.

As an aside, the cachet built-up around higher age statements was largely cooked up during a period of significant down-turn in the whisky market. With lots of excess inventory sitting in warehouses slowly aging, the whisky industry began pushing higher defined age statements as a sign of quality. In reality, they are a sign of cost – the longer that barrel has sat on some rack, the more it has cost the producer to store it (and so, the more you are likely going to pay for it). Given the recent resurgence of whisky consumption, there is now much talk of aged whisky shortages. Along with this is a move by distillers to release new No Age Statement (NAS) expressions, to better manage their inventories.

The furor over this has been extreme, as it is widely seen by many as a way for distillers to lower the quality of the final product (without necessarily lowering price). I don’t intend to wade in on this topic, but you should be aware it is a frothy field for discussion on most blog sites.

“Single Malt” vs “Blended” Whiskies

Back to the topic at hand – so, if that is what constitutes a “single malt”, what on earth is a “blended whisky” then? Blended whiskies (which are estimated to make up >90% of all scotch whisky sales worldwide) are blends of single malt whisky and so-called “grain whiskies”. Now, the pedantic among you may note that barley is indeed a grain. 😉 The distinction is that “malt” whisky is made exclusively from malted barley, prepared in a traditional way and distilled using a small batch pot-still method. As such, it is still more of a hand-crafted “artisanal” product – although one currently practiced on an incredibly large scale, as shown in the accompanying picture.

“Grain whisky” in contrast is produced by a much simpler and more economical method, using a continuous column still that is an example of the 19th century industrial revolution at work. This method produces a lot more whisky more quickly, on a truly industrial scale (i.e., grain distilleries truly are factories, in the classic meaning of that term). Column stills don’t require malted barley, and instead use a wide variety of economical grains – with corn, wheat, rye and unmalted barley being most commonly used.

So why don’t we just use this cheaper grain whisky method exclusively? It seems that the small batch method used to produce single malts still imparts the greatest variety of base whisky flavours. The effects of (and need for) maturation in wood barrels are also somewhat different for typical malted barley and grain whiskies. According to the experts, grain whiskies require longer in barrels to become truly interesting. But it also seems that they are also more “drinkable” at a young age than most single malts.

What this all means is that, by definition, grain whisky is cheaper to produce and age, as it doesn’t seem to need to spend as long in wood barrels to be considered good enough to sell. Traditional single malts do typically have a flavour advantage over grain whiskies though. This is why most scotch whisky connoisseurs quickly migrate to single malts, for the wide diversity of flavour they can provide. That said, outstanding grain whiskies can be produced – as you will see in my discussion of practices elsewhere in the world.

Price Points and Consumer Choice

For many casual consumers, traditional low-cost blends can provide the best price/performance trade-off. Again, in terms of scotch specifically, blends denote a mix of malt whiskies and grain whiskies. The mix will vary according to the brand and expression, but typically these are mainly grain whiskies, with some select malt whisky thrown in to liven things up a little.

To use a baking analogy, have you ever tried using synthetic versus all-natural vanilla extract? The synthetic version contains just the principal chemical component of vanilla, and doesn’t provide the full experience of the natural extract. But you can buy synthetic vanilla with a small amount of natural extract added in (e.g. 20%). This typically does a good enough job that you can’t taste the difference from full extract in the final product. It’s not a perfect analogy for our purposes, since the grain whisky in question here is still a whisky. But it doesn’t help explain why blends are the predominant output for this industry.

But again, there should be outstanding blended whiskies out there – just as there are outstanding single malts. These can be hard to come by though, given the fact that single malts are available to fill that high-end market niche. As a result, most blends focus on the low-end of the market. But there is no reason why high quality blends can’t be made – and I encourage readers to explore the wider world of international whiskies to find some outstanding examples. You don’t even have to venture too far geographically – several blended Irish whiskeys are also quite popular with discerning whisky drinkers.

Source of Whisky Flavours

But let’s get back to why single malts of “vatted” in the first place. To understand this, you must consider what imparts the actual flavours to a whisky. Please see my whisky flavour page for more information on this point.

Given that each barrel of whisky is unique, how on earth do distillers keep a consistent product on store shelves?

The answer comes down to blending (aka vatting). The reason your Glenlivet 12 year old (or any other single malt) continues to taste the same from bottle to bottle is that it is made in giant batches where they blend together many hundreds of individual barrels. These sources barrels are not blended together at random. The Master Blender of the distillery is following a general recipe (i.e., so many barrels of this age, so many of that cask type, etc.) that he or she adjusts on every batch to ensure overall consistency.

There are other strategies, depending on the product. For example, most bourbon is made from a custom mash bill that is distilled and aged in new oak barrels, in a consistent way. To overcome natural variation (including environmental differences throughout the warehouse), the complete output of a batch may be blended together before bottling. Of course, that doesn’t work with Scotch, where you are trying to craft a distinctive product from multiple independent sources (be they from the same distillery or not).

How Consistency is Maintained Across Batches in Scotch



This is done by some variant of a common method, for both so-called single malts and blends. The master blenders of the distillery (or third-party bottler) will start with a general recipe of the individual whisky casks required to produce the final flavour components of their brand’s signature taste.

But of course, no two individual whiskies will ever be the same – even if prepared in exactly the same way. There are just too many natural sources of variation at play (right down to regional variations in temperature and humidity in the warehouse, state of wood in the casks, etc.). As such, the master blended will need to alter the relative amounts of individual components in an attempt to achieve a consistent finished product.

Note that this requires the use of highly experienced tasters – those who can appreciate the individual components of each whisky that go into the mix. These individuals are highly prized by any distillery, as they are key to getting consistency in the final product.

Starting with a general recipe (that gets uniquely revised each time), the individual whisky casks are poured together into giant vats – typically huge stainless steel drums. The volume of these vats can easily be in the tens of thousands of liters (maybe more in some cases). Typically, the whiskies are left to “marry” for a period of time this way – potentially even for months. In some cases, this “marrying” may involve storing the mixed product in well-used wood casks for a period of time before reassembling the final batch. Time is money here, and you can’t always afford to have your blending vats tied up for extended periods.

The next step is to compare any new potential batch to an exemplar from the previous batch (i.e., a reference standard). Note this doesn’t have to be some absolute standard – simply using the last bottled version is good enough. The comparison is done using some variant of blind A-B testing. For example, a common method apparently involves pouring two glasses from the old batch, and one glass from the new. The experienced tasters are blind as to which glass is which. They are then asked to identify the “odd man out” (i.e., which one tastes different from the other two). If they consistently identify the new make as being different (as is likely initially), the master blended has to go back and adjust the relative contents of the new batch by adding new whiskies in, and trying the blind comparison tasting again. Once you get it to the point where the tasters cannot consistently differentiate the new from the old, you are good to go ahead and bottle.

Of course, that’s in an ideal world. Practically, distillers have to accept some “slippage” in flavour matching over time, due to the limited availability of source stock. Once it becomes untenable to continue to keep calling something under the same label as previously used, the distillery will need to come up with a new designation for this product. After all, no one is going to flush those tens of thousands of liters of whisky down the drain. Time for a special “Founders Reserve” release anyone? 😉

Why Whiskies Really Taste Different

Suffice it say, there are real reasons why whiskies taste different from each other – and it has everything to do with the differing processes for production, aging and blending performed by each of the distillers. These can certainly depend on the historical methods of malting and extraction, the types of stills used, availability of barrels, etc. But it is the culmination of all the techniques and processes employed by the skilled craftspeople all down the line that matter, not the starting material. And at the end of the day, it is really the master blenders who create the final engineered product that you enjoy, from the constituent components that they have on hand.

And so, make no mistake about it – whisky is an engineered product.