Caramel colour is widely used, but some whisky enthusiasts are opposed to it: (2001) http://www.just-drinks.com/analysis/caramel-addition-may-prove-sticky-issu

Caramel colour is widely used, but some whisky enthusiasts are opposed to it: (2001) http://www.just-drinks.com/analysis/caramel-addition-may-prove-sticky-issue-for-scotchs-marketeers_id85433.aspx http://www.just-drinks.com/analysis/caramel-addition-may-pro... (2011) http://www.masterofmalt.com/Blog/post/Can-you-taste-Caramel-(E150a)-in-Whisky.aspx http://www.masterofmalt.com/Blog/post/Can-you-taste-Caramel-... It's definitely an enthusiast/purist attitude, but common enough that some distilleries now specify "natural colour". Even large whisky producers like Diego have natural colour product lines: http://www.diageo.com/en-row/ourbrands/categories/spirits/Pages/Whiskey.aspx#knockando http://www.diageo.com/en-row/ourbrands/categories/spirits/Pa... The actual impact of artificial colour on taste/aroma/overall experience is likely negligible, but I wanted to point out that it is an issue to some.