When enjoying a glass of whiskey I often hold up my glass to the light and watch how the light plays with the color. I always wondered how the whiskey got its color and why it is a hue of brown. I did some thorough research including asking staff at a Scottish distillery and found the answer.
Why is whiskey brown?
Whiskey gets its color from the wood of the barrel it ages in. The charred oak on the inside of the cask gives the whiskey a deep brown color. The longer the whiskey is in the cask, the darker the color. Some distilleries artificially add color with E150a, also called caramel coloring.
Interestingly, the color of the whiskey can also influence our flavor experience. And there are also whiskeys out there that are as clear as vodka! How does the climate influence the color of the whiskey? All these things are briefly covered in the rest of the article!
How does whiskey get its brown color?
The whiskey receives its brown hue because it comes into contact with the wood from the cask. The whiskey is a good solvent due to the high alcohol concentration, which allows wood sugars, tannins and pigment to dissolve in the whiskey. During warmer periods the whiskey expands and gets forced into the wood. When it gets colder the wood contracts and pushes the whiskey back into the cask. This process repeats itself over and over, giving the whiskey its color.
All whiskeys are aged in a wooden cask. Often these casks are made from oak wood. The whiskey can be aged in a brand new oak cask, a used oak cask, but also in casks that were previously used to store sherry, port, rum or wine. The type of cask used to age whiskey has a big effect on the flavor of the whiskey, but can also have an effect on the color.
Sometimes a whiskey is also aged in multiple casks. An example would be a whiskey that starts in an oak cask but finishes in a sherry cask.
Whiskey is often aged for multiple years, so the pigment of the wood has a lot of time to get dissolved in the whiskey. The longer a whiskey ages, the darker the color. This makes sense, as the coloring is a slow process. You could compare it so a really slow tea bag.
Usage of caramel coloring (E150a)
People will generally argue that an older whiskey has a more complex flavor profile. I would agree (although some younger whiskeys can be really surprising and interesting), but the price of a bottle also definitely agrees. Keeping a whiskey for longer means more risk for the distillery. Things can go wrong and they can lose a valuable batch of whiskey. There is also way less whiskey left in a cask as a big part evaporates over the years (the part that evaporates often is called the angel’s share).
To mimic an older whiskey, some distilleries add caramel coloring to the whiskey. While it sounds like something to pour over your ice-cream, it actually is something that is cooked so heavily that it ends up tasting bitter instead of sweet. I know right, this does not sound like something I would want to add to my whiskey. However, caramel coloring is near impossible to taste and only affects the color. The use of the word “caramel” sounds like we would be talking about altering the taste, but it really is just about the color of the drink.
If caramel coloring is used, it does not have to be mentioned on the label. This makes the subject a bit controversial, as caramel coloring can hide a poorly aged whiskey.
Bourbon and American whiskeys that say “straight” have not added any caramel coloring as this is against the law. Scotch whisky, as well as Canadian, Irish and other American whiskeys are allowed to use E150a and do not have to state if and how much they have added. In Germany distilleries are encouraged to state it on the bottle, look for the words “Mit Farbstoff” which translates to “With Coloring”.
The reason why distilleries use the coloring is to keep the color of different batches consistent. Another reason is because consumers associate a darker colored whiskey with a higher quality.
Difference between Scotch and Bourbon
Bourbon is always aged in new “virgin” charred oak casks, whereas Scotch is mostly aged in used casks. Bourbon casks are only allowed to be used once, after which they are sold to the rest of the world (including Scotland).
When the cask has not been used before, the effect of the wood is way stronger compared to a cask that has been in use for decades. Again, compare it to a tea bag. The first tea – I mean whiskey, will be way darker than the second, third or even fourth batch.
This is one of the reasons that a 10, 12 or even 20 year old Scotch can still be pretty light in color. The other reason has to do with the climate in which the whiskey is aged.
Effect of the weather on the whiskey color
Whiskey that has been aged in a warmer climate does not have to be in a cask nearly as long as whiskey that has been aged in a more temperate climate. This is another reason why we are able to buy 20+ year old Scotch whisky, but 20+ year old bourbon is less common.
This all has to do with the temperature. As you may remember for your science classes, heat speeds up a reaction. This also goes to the time it takes for all the tannins and vanillins to dissolve into the spirit. Another important factor is the evaporation of water. In warmer temperatures, the water evaporates way quicker. This means that a Scottish distillery that left their barrel for 20 years is left with way more liquor compared to a distillery in Florida.
Here is how the color can affect our whiskey drinking experience
A darker whiskey is associated with a higher quality whiskey. This is also one of the main reasons why adding a coloring is so tempting to distilleries. If you are a Scottish distillery and have been using the same used bourbon barrel for 30 years, the whiskey that comes out will not be as dark as consumers expect a 25 year old whiskey to look like.
What makes it difficult is that brands to not have to say whether or not they have added coloring to their product. This leaves people guessing at if and how much the color will deviate from the original product.
What about white whiskeys?
In the more recent years, more white whiskeys have been coming to our stores. Is it whiskey? yes! But why then does it not look anything like the whiskeys we are used to drinking. This is because the whiskey has barely touched a barrel before being bottled.
White whiskey offers the perfect opportunity for new and smaller distilleries to release a product before releasing a respectable, aged whiskey. It is not allowed for these distilleries to directly bottle the spirit that came out of the stills, as this would not be whiskey.
A news article over at chicagotribune.com talks about Death’s Door White Whiskey, which is produced in Madison, Wis. and is aged for just 72 hours.
The result? A clear spirit that looks like vodka and smells somewhere between vodka and tequila.