Dark chocolate is any chocolate that contains at least 35% cocoa solids, according to FDA standards. That’s the minimum threshold for a product to be labeled “dark chocolate” in the United States. But the category spans a wide range, from mildly bitter bars at 35% all the way to intensely concentrated chocolate at 85% or higher, and the percentage you choose makes a real difference in flavor, sugar content, and nutritional value.
The Official Definition
The FDA draws the line at cocoa solids, the ground-up components of the cacao bean that give chocolate its characteristic color, flavor, and bitterness. Dark chocolate must contain at least 35% cocoa solids. Milk chocolate, by comparison, only needs 10%. White chocolate contains no cocoa solids at all, which is why it’s technically not chocolate in the regulatory sense.
The other defining feature is what dark chocolate leaves out. Unlike milk chocolate, dark chocolate does not contain milk or milk solids. Its ingredient list is simpler: cocoa solids, cocoa butter, sugar, and sometimes an emulsifier like lecithin and vanilla. Without milk diluting the cocoa, dark chocolate delivers a more intense chocolate flavor and retains more of the beneficial plant compounds found naturally in cacao.
Semisweet, Bittersweet, and Extra Dark
Within the dark chocolate category, you’ll see several terms on packaging that signal different intensity levels. These aren’t tightly regulated, but the industry follows general conventions. Semisweet chocolate typically contains around 60% cacao, making it the sweeter end of dark chocolate and the most common type used in chocolate chip cookies and everyday baking. Bittersweet chocolate sits around 70% cacao with noticeably less sugar. The flavor is deeper and more complex, with fruit, nut, or earthy notes depending on the origin of the beans.
Beyond 70%, you move into extra-dark territory. Bars labeled 85% or 90% cacao are intensely bitter with very little sweetness. These appeal to people who genuinely enjoy the taste of roasted cacao, but they can be an acquired preference. For cooking, the distinction matters: if a recipe calls for bittersweet and you substitute semisweet, you’ll need to reduce the sugar elsewhere to compensate for the sweeter chocolate.
Why Percentage Matters for Health
The percentage on a dark chocolate bar tells you the total amount of cacao-derived ingredients, both cocoa solids and cocoa butter. A higher percentage means more cocoa solids (where the beneficial plant compounds live) and less room for sugar. A 70% dark chocolate bar is roughly 30% sugar and other additions, while a 50% bar could be nearly half sugar by weight.
Dark chocolate is a notable source of flavanols, a type of plant compound with antioxidant properties. These are the same compounds behind most of the cardiovascular research on chocolate. Large observational studies have found that people who eat chocolate regularly tend to have a lower risk of heart disease. One study found that consuming more than about 45 grams per week (roughly a third of a standard bar) was associated with a 20% lower risk of stroke compared to those eating very little. Another found an 18% lower risk of coronary heart disease among the highest consumers after adjusting for inflammatory markers.
These are observational findings, not proof that chocolate itself caused the benefit. But the flavanol connection is well established in shorter-term clinical research showing improvements in blood pressure and blood vessel function. If health benefits factor into your chocolate choices, bars with 70% cacao or higher will give you the most flavanols per serving while keeping sugar relatively low.
How Processing Changes the Chocolate
Not all dark chocolate with the same cacao percentage delivers the same nutritional profile. The way cocoa is processed has a dramatic effect on its flavanol content. Natural cocoa powder, the kind that’s light brown and slightly acidic, retains the most flavanols. Dutch-processed cocoa, which is treated with an alkalizing agent to mellow the flavor and darken the color, loses a significant portion.
Research published in the Journal of Agricultural and Food Chemistry measured this directly. Natural cocoa powders contained an average of about 34.6 mg of flavanols per gram. Lightly Dutch-processed cocoas dropped to 13.8 mg/g. Medium-processed cocoas fell to 7.8 mg/g. Heavily processed versions retained only 3.9 mg/g, roughly one-ninth of what natural cocoa delivers. If you see “processed with alkali” on the ingredient list of a dark chocolate bar or cocoa powder, the flavanol content is substantially reduced even if the cacao percentage looks impressive.
Heavy Metals in Dark Chocolate
Dark chocolate can accumulate trace amounts of lead and cadmium from the soil where cacao is grown and from processing steps like drying and roasting. A multi-year analysis of 72 dark chocolate products sold in the U.S. found that 43% exceeded California’s conservative daily exposure limits for lead and 35% exceeded limits for cadmium. However, 97% of products fell below the FDA’s own reference levels for lead, which are set higher.
The median contamination levels across all products tested were actually below even the stricter California thresholds, suggesting the problem is concentrated in certain brands rather than the category as a whole. Interestingly, organic products were significantly more likely to contain higher levels of both cadmium and lead. For most adults eating a single serving of dark chocolate a day, the exposure from a typical product is unlikely to pose a meaningful risk. The concern increases with heavy daily consumption, in children, and during pregnancy. Varying the brands you buy is a simple way to reduce cumulative exposure from any single source.
What to Look for on the Label
When shopping for dark chocolate, the cacao percentage is your most useful number. Here’s a quick reference for how the range breaks down in practice:
- 35% to 55%: Meets the minimum definition of dark chocolate but tastes relatively sweet. Often used in candy bars and mass-market products. Lower in flavanols, higher in sugar.
- 55% to 70%: The semisweet to bittersweet range. A good balance of chocolate flavor and moderate sweetness. This is where most “everyday eating” dark chocolate falls.
- 70% to 85%: Noticeably bitter with complex flavor. The range most commonly recommended when health benefits are a consideration.
- 85% and above: Very bitter, very low in sugar. Best for people who have developed a taste for intense cacao or for use in savory cooking.
Beyond percentage, check the ingredient list. The shorter, the better. Cocoa mass (or cocoa liquor), cocoa butter, and sugar should be the primary ingredients. Avoid bars where sugar is listed first, as ingredients appear in descending order by weight. If you care about flavanol content, look for bars that don’t mention alkali processing, and favor those that list cocoa mass or cocoa liquor rather than just “cocoa powder,” since the whole liquor retains more of the bean’s original compounds.