What Gives a Whisky Its Colour?The colour of a whisky is a result of contact with the oak barrel the whisky matured in, so the size and condition of the barrel, it’s previous content and maturation all affect the colour of your whisky. The older the whisky the darker you can expect it to be, though this can’t be said in reverse a dark whisky is not always indicative of an older age statement.
Melanoidins From the Oak BarrelWhen whisky, technically called new make spirit until its at least three years old, is first distilled it is crystal clear with no trace of colour when it arrives in the spirit safe. The whiskies colour is primarily the consequence of melanoidins (high molecular weight heterogeneous polymers) which are created during the breakdown of cellulose. The longer a whisky has been aged the darker the spirit generally is.
Condition of the BarrelAmerican law requires that any bourbons must be matured exclusively in new oak barrels, Scotch, and most other whiskies have no such restrictions. As a consequence bourbon’s are typically much darker than other whiskies of comparable ages. It’s not unknown for Scotch distillers to re-use barrels three or even four times before these are scraped and re-charred, a process referred to as rejuvenation, each subsequent use means results in a lighter spirit than would have been achieved during the previous maturation. For this reason first fill whiskies, whiskies matured after these have been used for bourbon, are often prized above others
Barrel SizeSmaller barrels by virtue of having a lower wood surface to spirit ratio, and of course less whisky, result in a much darker hue than would be achieved by a larger barrel. A quarter cask with an 80 litre capacity or American bourbon barrels with a 190-200 litre capacity for example will result in a far darker whisky than could be achieved with a 250 litre Hogshead. While American bourbon barrels are by far the most common source of staves used to produce scotch it’s not uncommon for these to be turned into considerably larger barrels when reassembled by the cooper.
The Previous ContentThe history of the barrel has a huge impact on not just the flavour profile but also the colour, whisky matured in American oak barrels (Quercus alba) from the American bourbon industry will result in a golden yellow or honey colouring, whisky matured in European oak (Quercus robur) sherry buts will result in a much darker amber hue. While the below list is not exhaustive it gives a useful overview of the impact the previous resident can have on a whisky colour profile;
|Predecessor||Type of liquid||Resultant Colour Change|
|Madeira||fortified wine||dark, amber|
|Port (sweet)||fortified wine||red|
|Port (semi-dry)||fortified wine||red|
|Port (dry)||fortified wine||red|
|Pedro Ximenez (PX)||sherry||amber|
|Sauternes||wine||bright to amber|
|Tokaji||wine||bright to amber|
|Ruby Port||fortified wine||red|
|Marsala||fortified wine||dark red|