Best for On-the-go snacking; cool weather
Beta Darker bars with a higher proportion of cocoa solids are healthier and less likely to melt; in testing, some didn’t soften until temps hit the high 80s. Thicker bars (Cadbury’s Royal Dark was the heftiest at 1/3 of an inch) held up to pack abuse best.
Packing Keep bars above freezing and below 75°F. Store in plastic in your pack’s center.
Buying tip Our testing revealed that gourmet brands showed less chalky-looking “bloom” after extreme temps—the fat and sugar residue looks bad, but is edible.
Top pick We love Dagoba Organic’s New Moon Bar, with 74 percent cocoa ($3; 2 oz.; dagobachocolate.com; available at Whole Foods). It’s the sturdiest bar we tried, and the least bitter for the high cocoa content.