An 8-Hour Bread That’s Worth the Wait

Why bother to bake a bread for 8 hours? That was our question when testing Icelandic dark rye bread. On the island, loaves are steamed underground in geothermal fields for nearly 24 hours. You can achieve a similar result in an oven set at ultralow heat. The long, low cooking deepens the bread's flavor and color. Given time to transform, the enzymes in the rye flour convert starches into sugars, and amino acids and free sugars go through reactions that lead to caramelization. The glucose in the golden syrup used in the dough helps retain liquid during cooking, making for a dense, moist, sweet-malty bread. Worth it? You bet.