Quite simply, not always. Dark chocolate can be vegan, of course, and there are great vegan dark chocolate bars being made these days. But just because there are no animal products directly put in chocolate doesn’t mean that animal products haven’t played a role in their production at some point, deeming them non-vegan friendly.
Therefore, the only vegan dark chocolates you can be sure are vegan-friendly are ones made by companies with vegan values, like Charm School Chocolate or Raaka Chocolate. Most commonly, the factor which makes dark chocolate not vegan friendly is the sugar. Cane sugar, the cheapest and most common sweetener used in chocolate making is not vegan unless it’s organic and/or raw. That is because the way in which cane sugar is processed includes the use of animal bones in order to bleach it to such a uniform white color.
To find vegan dark chocolates you can trust in the supermarket, look for products which don’t contain cane sugar, but some kind of vegan-friendly alternative. Options include, but are not limited to, monkfruit or coconut sugars, and sugar alcohols such as maltitiol or erythritol. These chocolates tend to be more expensive, and are definitely harder to find. But it’s worth the search to be able to stick to your values, and end up with a more delicious product in the end. Vegan dark chocolate can be much tastier than the alternative!