Color and clarity
Coloring & chill filtration
Two techniques alter the appearance of a whisky without touching its age or origin: caramel coloring for color, and chill filtration for clarity. Both are permitted in some countries and legally banned in others.
Why whisky gets colored in the first place
Whisky gets almost all of its color from the wooden cask. Yet the same grain can take on completely different shades depending on the cask, storage location, and chance — anything from pale straw to deep amber. Buyers often unconsciously associate a darker color with more maturity or more flavor, even though this isn't scientifically accurate. To deliver a consistent look from batch to batch, many distilleries turn to caramel coloring, listed as E150a in ingredient lists.
E150a, also known as plain caramel coloring, is produced by heating sugar without any additional additives. Under food law, it's considered flavor-neutral. Under EU Regulation 2019/787 and the Scotch Whisky Regulations, it's the only permitted additive besides water, and Irish Whiskey follows the same rule. A note about E150a doesn't necessarily need to appear on the whisky label itself. In most countries, spirits aren't required to carry a full ingredient list, unlike beer or soda.
Why US law bans added coloring
In the US, exactly the opposite applies to Straight Bourbon and Straight Rye: added coloring is banned. The US regulatory body, the TTB, requires that every shade of color come solely from contact with the charred oak cask — nothing else is allowed to help it along. Only a few non-straight American whiskeys are permitted to contain a small amount of caramel coloring. For the flagship category of Straight Bourbon, though, it remains completely off-limits.
This difference explains why you'll almost never see a note about added coloring on an American bourbon shelf. There, it's already ruled out by law. With Scotch, on the other hand, it's worth checking the label. If it reads Natural Colour or no added color, the distillery has deliberately skipped E150a, usually as a quality statement aimed at connoisseurs.
Chill filtration: clear, but not without consequences
When whisky is diluted with water, or simply gets cold — say, from ice cubes — certain fatty acids and esters can precipitate out. These occur naturally in the drink and create a fine haze known as chill haze. This is harmless in terms of flavor, but many buyers perceive it as a flaw. To prevent this, distilleries chill the whisky before bottling to temperatures between minus ten and four degrees Celsius. They then filter it through fine filter layers that remove these compounds, usually eighty to ninety percent of them.
The downside: these very fatty acids and esters also contribute to texture and depth of flavor. Critics of chill filtration therefore claim it noticeably reduces mouthfeel. More and more bottlings are now marketed as Non-Chill-Filtered or unfiltered, deliberately skipping this step, often paired with Natural Colour on the same label. No country legally requires chill filtration — it's purely a producer's choice made for consistent appearance.
How to spot both on the label
Look out for three possible clues. Natural Colour means no caramel coloring, Non-Chill-Filtered means no chill filtration, and both terms together promise a whisky as close as possible to its condition straight from the cask. If none of these three terms appear, it usually means the distillery has used both standard processes without specifically mentioning it.
For Straight Bourbon from the US, mentioning added color is unnecessary anyway, since the law already excludes it. Chill filtration, on the other hand, is permitted and widespread there, though rarely advertised. So if you're looking for the most unaltered result possible, you'll find the clearest clues on European and British labels. A second glance at the label only takes a few seconds and sharpens your eye for the next bottle.