When you scratch the surface of all booze related products the romance seems to fall away and becomes simply an extension of the marketing jargon. It is not uncommon for wine producers use wood chips to add that “oak’ character to some chardonnay for example. In the same way, some producers use caramels to intensify the look of their spirits. 

According to the Scotch Whisky Act of 2009, which basically sets and/or updates standards for Scotch production, Scotch was and remains a spirit “to which no substance has been added except (i) water; (ii) plain caramel colouring; or (iii) water and plain caramel colouring.” 

Further, according to the article Answering The Whiskey Caramel Coloring Question

In America […] According to the Alcohol and Tobacco Tax and Trade Bureau, some American whiskeys are allowed to add up to 2.5% of caramel coloring. However, this does not apply to bourbons that are labeled “straight,” meaning the color from straight bourbon must come only from the barrel, and not any additives. 

A common question is “which is better?” the answer is simple- they are all great, it just depends what you enjoy. Some people love the bandaid/smokey flavor of Laphoig (for example), others find it rancid and it turns them off scotch all together. A well made blended whiskey from Japan aged in the best Mizunara Oak Barrels could offer more enjoyment than a single malt scotch. It is a personal journey that needs to be encouraged.   

If you are looking for some good 


Single Grain

While this term can be easily confused with ‘single malt’ due to its similarity, it is important not to get the two confused as they are quite different. One factor they do have in common is that the ‘single’ in both terms refers to the ruling that each whisky must be produced at a single distillery. However, the main difference is that single grain whiskies do not have to be produced from malted barley. In fact, other cereals such as wheat, corn or rye could all be used, and they can be malted or un-malted. As a result, single grain whiskies are usually light bodied and tend to offer sweeter notes over smoky aromas.

Single grain whiskies also differ from single malts in how they are distilled. Single malts are distilled using traditional pot stills, while single grains are distilled in column stills (or Coffey stills). Pot stills operate on a batch by batch basis and are used primarily for creating a flavourful product. On the other hand, column stills can be used to produce whisky of a high ABV on a more industrial scale. Therefore, single grain whiskies aren’t usually bottled alone (with a few exceptions) but are commonly blended with malts to create blended scotch whisky.


Blended Scotch Whisky

As we mentioned earlier, different whiskies are often blended together. The need for blending arose because, at the time, single malt scotch had a very strong and raw flavour that not everyone enjoyed. Through blending, Usher was able to create a scotch that had a milder flavour and appealed to a wider market. Today, about nine out of every 10 bottles of scotch sold worldwide are sold as ‘blended scotch whisky’. Pre-2009, any mix of scotch whiskies could qualify as a blended scotch. However, the Scotch Whisky Regulations now state that blended scotch whisky has to contain a combination of one or more single malt scotch whiskies and one or more single grain scotch whiskies.

The ratio of grain to malt in the blend varies from bottle to bottle. The grain forms the body of the whisky, while the malt gives the whisky additional flavours. As a result, more expensive blended scotch whiskies will tend to use a higher percentage of malt in their blend.

Alongside this new legislation came two new blended whisky categories: ‘blended malt scotch whisky’ and ‘blended grain scotch whisky’. While ‘blended scotch whisky’ previously encompassed all of these terms, the change to what exactly defined a blended scotch whisky required these two new classifications to be introduced. Blended malt scotch whisky means that it has been made from a blend of two or more single malt scotch whiskies from different distilleries. Similarly, a blended grain scotch whisky is the blend of two or more single grain scotch whiskies from different distilleries. Blended malt scotch is the more common of the two, however there are a few distilleries who sell blended grain scotch for the truly curious whisky connoisseurs out there.


So, to summarise –

Single Malt Scotch:

Scottish whisky produced by a single distillery.

Can only be made using barley and water.

Single Grain Scotch:

Scottish whisky produced by a single distillery.

Can be made using any cereal, including wheat, corn or rye.

Blended Whiskies:

Blended Scotch Whisky – a blend of one or more single malt scotch whiskies with one or more single grain scotch whiskies from different distilleries.

Blended Malt Whisky – a blend of two or more single malt scotch whiskies from different distilleries.

Blended Grain Whisky – a blend of two or more single grain scotch whiskies from different distilleries.

As is the case with most products, a general punter may find it hard to distinguish between one product and another. This is true (in part) for whiskey as well. A high quality blended whiskey can give as much enjoyment as a single malt for both the general punter and a whiskey aficionado. The Australian Bartender Magazine article The Scotch whisky rules: within the rules, there’s still room to surprise outlines a study which found similar results. 

What are the major factors in the flavor difference in whiskey? 

The Grain

The production rules

The Aging requirements

The Blend


Filling of spirits in oak is usually done at 65% abv, scotch whiskey is typically approx. 63-65%.

A major influence of ageing beverage in oak is the temperature and climate that the product ages. For example, wine can be aged in caves or underground bunkers, or in the case of bourbon in warehouses where temperature can differ up to 35 degrees from the top floor to the bottom floor (see https://www.diffordsguide.com/en-au/encyclopedia/482/bws/barrel-ageing-cask-maturation-of-spirits). It should be noted that the ‘angels share’ will be predominantly water on the top floors to alcohol in the cooler floors due to the temperature. 

There are four main impacts on the final product- 

1.    Climate in the ageing process- refer to bourbon and cave ageing as examples

2.    Oak type- refer to cognac/Armagnac, chardonnay and also sherry

3.    Time in Barrel- add in notes on solera (don’t delve too deeply) whiskey and rum

4.    Size of barrel- obvious

5.    Old oak or new oak or combination

6.    Level of char on the oak- see https://talesofthecocktail.org/techniques/what-you-need-know-about-barrel-char-primer-four-levels/


Oak has been used for thousands of years to age all manner of beverages. It has been proven to contribute complementary flavours while still remaining relatively neutral when compared to other woods. There are four main oak types used for ageing- each having a unique impact on the final product. 

American oak is typically grown in colder regions like Minnesota as the cool climate slows the growth of the tree subsequently encouraging a tighter grain. The oak imparts vanilla notes along with caramel and hazelnut characters. 

European oak from Spain and Portugal is mostly used in the wine industry as a primary ‘First Fill’ barrel, then used again for whiskey and rum ageing known as a finishing barrel. Typical characters are dates, raisons, and cloves. The ageing of sherry is barrels is done over a very long period and as a result a more neutral flavour profile is desired. 


Michters Bourbon- dry wood for 18-48 months, char their wood at approx. Level 1, at 51.5% ABV when entering cask (typically 63% approx.) encourages heat cycling to get maximum impact form the wood. 

Wild Turkey- They use Level 4 char 

There are too many variations on in the maturation of spirits in oak to say that one factor determines the final product. Bourbon Regulations restrict producers to using new, freshly charred oak barrels. Charring in barrels ranges from Level 1 (15 seconds burn) to Level 4 (55 seconds burn) which is often referred to as Alligator Char for obvious reasons. The level of char allows the spirit to penetrate the wood by increasing surface area while affecting the compounds in the wood which effect the final taste. (see https://flaviar.com/blog/using-oak-barrels-to-age-bourbon). It is most common for Level 4 char to be used as this has a more pronounced impact during maturation.  Michter’s, a reputable Bourbon producer uses a Level 1 char to great effect, but also employ various techniques to enhance final product. 

ALL ABOUT PEAT- https://www.theyorkshiregent.com/whisky/the-scotch-whisky-peat-scale-explained/


Fermentation and the impact of flavor


Fermentation is used in the creation of all of your favorite drinks, from beer and wine, all the way to brandy, tequila, and rum. Simply put, fermentation is the stage in spirit production where alcohol is created. Before fermentation, what whisky distilleries basically do is create an extremely sugary, grainy water, which they call wort. Yeast is then added to the wort, in order to convert fermentable sugars into alcohol.

Distilleries all have their own fermentation regime. Some might opt for a short fermenting period, as alcohol production dramatically declines after about 48 hours, when most of the yeast dies out. What you’re left with is basically a strong beer (roughly 7 or 8 percent alcohol), without the hops. Others will opt for a longer fermentation, sometimes over a hundred hours. Not much alcohol is produced in those latter stages, but new heights of aromatic complexity can be reached.


Wooden washbacks—the vessels in which fermentation takes place—made from Oregon pine not only look impressive, but they also ooze tradition and alter the entire look of a tun room. Steel washbacks just don’t have the same transformative visual effect. Ultimately, though, the difference in appearance between the two types is not very significant.

Scotch Fermentation: Wooden Washbacks

What is significant is the difference between fermentation in wood or steel. Wooden washbacks have an insulating quality, protecting the fermentation from the cold, which sometimes comes in handy in winter. The most important difference between the two is this: steel is more easily cleaned and requires less maintenance, while wood harbors certain bacteria that have their own profound influence on flavor creation. In the end it is not so much a question of which type of washback is better; it is a matter of which a distiller prefers.


Important chunks of flavor in the soon-to-be-whisky are created during fermentation. There are lots of variables at play here, all with a potentially major impact on the final flavor profile of the whisky. The microclimate inside the distillery, the temperature of the fermentation, the amount and type of yeast used, the length of the fermentation; they all affect the end result.

While fermentation is in essence all about alcohol creation, an important byproduct is the formation of flavor compounds. Yeast basically eats the sugars that are part of the wort, breaking them down into alcohol and carbon dioxide. The yeast then transforms some of the alcohol into flavor compounds, like esters, renowned for contributing fruitiness.

Scotch Fermentation: Washbacks at TomatinSteel Washbacks at Tomatin / Photo Credit: Thijs Klaverstijn

In the latter stages of fermentation, when the yeast has quieted down, lactic acid bacteria become active. The chemical reactions ignited by these bacteria will lead to the creation of more esters, acids and long-chain alcohols. They are the compounds that will mostly survive the ensuing distillation, and interact with each other, the air and the wood once the new make spirit is filled into barrels.


Fermentation is about so much more than creating alcohol. Obviously, without alcohol, there is no whisky. However, without all those flavor compounds generated during this important part of whisky production, you’d end up with an incredibly bland and unrecognizable product. Brands might not talk about it in their marketing, but distillers are acutely aware of the value of fermentation. When it comes to scotch fermentation, creating complexity is the name of the game.

Yet again Diffords Guid provides a brilliant explanation to the whole fermenting process…


 The longer it goes on, the more acidic the wash becomes and the more esters are produced. In other words, it gets fruity. This is down to the lactobacilli (LABs) which lurk in the pipes and washbacks (particularly wooden ones) of every distillery. (https://scotchwhisky.com/magazine/features/9635/bacteria-the-key-to-distillery-character/)

 For a neat analysis of stills and flavor check out https://whiskysmiths.com/whiskey-wednesday-newsletter/2017/09/13/how-pot-still-shape-affects-whisky-flavor#:~:text=Since%20wider%20stills%20have%20more,spirit%20than%20their%20skinnier%20counterparts.&text=Shorter%20stills%20with%20less%20copper,produce%20a%20lighter%20tasting%20spirit.

Also this one: https://www.deviantdistillery.com/2018/07/17/still-shape-size-effect-whisky/

Influence of copper: https://www.deviantdistillery.com/2019/10/08/copper-whisky-spirit-stills/

Influence of peat: http://whiskyscience.blogspot.com/2011/02/peat.html