Most of the bars we tasted had pleasing, smooth textures, except for one that was gritty and grainy. The gritty bar was divisive; a few tasters loved the texture, but others said it was “almost like eating sand.” We generally preferred bars that were silkier, and our winner was extremely smooth. Our science research editor said two factors contribute to a chocolate bar’s texture: conching and cocoa butter.

During conching—one of the last steps in the manufacturing process (for most Western-style commercial products)—the chocolate is heated and constantly stirred (for more details, see “How Chocolate Is Made”). The result is a chocolate with a very smooth texture. The company that manufactures the gritty chocolate we tasted does not conche, which they say helps preserve the texture of the cacao and sugar. Most of the other companies confirmed their chocolate had been conched, and their bars were much smoother.

The other factor: cocoa butter, the fat in the cacao bean. Megan Giller, food writer and the author of Bean-to-Bar Chocolate: America's Craft Chocolate Revolution (2017) , told us that a bar made with added cocoa butter—more than the amount existing naturally in the bean—is typically smoother than one without added cocoa butter. That’s because cocoa butter is essentially fat. When we inspected ingredient labels, we noticed the grainy chocolate had the lowest amount of fat per serving in the lineup, 16 grams per 40-gram serving. The company confirmed this bar does not have any added cocoa butter. The remaining bars had much higher fat levels—21.3 grams to 24.2 grams per 40-gram serving (with our favorite bar having the most in the lineup)—and were much smoother.

Sugar levels were low across all of the bars—roughly 2 to 3 grams per 40-gram serving, compared to 15 grams in the same amount of our winning 60-percent-cacao dark chocolate. While sugar balances bitterness, we still saw a range of bitterness despite the bars having similar sugar levels: The experience of eating our least favorite bars was “like biting into a lemon,” while our favorite chocolate bar had a faint bitterness that was nicely balanced with sweet, fruity notes. Something else was going on.

Our science research editor said that a bar’s bitterness also corresponds to its ratio of cocoa solids to cocoa butter. Fewer cocoa solids means more cocoa butter—or fat—which produces a less-bitter chocolate. We used info from nutrition labels to calculate the amount of cocoa solids in each bar and found that our winner had the most fat and the fewest cocoa solids. So despite its 90-percent cacao content, it wasn't too bitter.

Tasters also noted a range of flavors—from stone fruit and berries to coffee and espresso. Curious to know what might cause this variation in flavors, we asked Giller, who told us, “Proper fermentation, drying, and storing procedures make a huge difference in flavor.” She added that the other major distinguishing factor in determining flavor is how long the beans are roasted and at what temperature, noting that lightly roasted beans will often have more acidity, which we can impart fruitiness, and strongly roasted beans convey toasty or fudgy flavors.

Bean origin matters, too. “Cocoa beans have terroir, just like wine grapes or coffee beans,” said Giller. Some chocolate is single origin, meaning the cacao beans used to make it come from only one location. Other products are made from blends of beans sourced from multiple places. The manufacturer of our favorite bar uses beans from Ecuador and the Dominican Republic. We asked Giller if beans from those countries had a specific profile that might contribute to our winner’s flavor and she said Ecuador's beans are often fudgy, while beans from the Dominican Republic, “often have a dried fruit sort of flavor—think prunes, dried cherries, raisins.” Indeed, several tasters picked up a rich cocoa flavor in our winning bar, as well as pronounced fruity notes that included cherries, berries, and peaches.

The clear winner was Alter Eco 90% Deepest Dark Super Blackout Organic Chocolate Bar, about $3.00 for a 2.65-ounce bar. We loved this bar’s supersmooth texture and optimal balance of bitter and sweet notes, with fruity undertones. One taster summed it up nicely: “I could eat a lot of this.”

Since we were already tasting a bunch of chocolates, we decided to go all-in and taste bars in the 80- and 70-percent-cacao ranges as well. After researching which brands were nationally available, we selected eleven in the 80- to 88-percent-cacao range, and another eleven in the 70- to 73-percent-cacao range. (Some companies offered multiple chocolate bars within a range, so we tasted them all in a blind taste test to select our favorite, and then added the winning bar to our final lineups.) Our tasting panel then tasted the chocolates in the two ranges and identified favorites in each.

The cacao percentages of the eleven bars in this lineup ranged from 80 to 88. As would be expected, these bars were generally more bitter than the 70-percent-cacao bars, but no less delicious. They had 5 to 5.7 grams of sugar per 40-gram serving, or roughly half the amount of the bars in the 70- to 73-percent-cacao range, and approximately double the amount in the 90- to 95-percent-cacao range. Overall, we applauded these bars’ mild sweetness; subtle flavor notes that included burnt coffee, pumpkin spice, and raspberries; and smooth textures. We picked up faint notes of coconut in our winning bar, which was Lindt Excellence 85% Cocoa.

The cacao percentages of the eleven bars in this tasting ranged from 70 to 73. Tasters loved the smooth textures of these bars. They had 10.5 to 10.7 grams of sugar per 40-gram serving (compared to 2.3 to 3.2 grams for the 90- to 95-percent-cacao bars), and tasters appreciated the sweetness, especially when well-balanced with a hint of bitterness. Flavor notes varied widely and included coconut, coffee, and even a hint of smokiness, with our favorite bar, Chocolove Organic Dark 73% Chocolate Bar, offering both a strong fruity flavor and a rich cocoa taste.