Lentils are close cousins to peas and beans, and like their kin they're a rich source of fiber, iron and vegetable-based protein. Dried lentils also cook much more quickly than beans thanks to their flat shape, so you don't need to soak them ahead of time before cooking. However, you can shorten your cooking time -- and reduce gas -- by soaking them briefly, and small lentils can be cooked by soaking in boiling water.
Lentils are among the oldest of cultivated crops, probably dating from around the same time wheat and barley were first domesticated. They remain a major staple throughout central Europe, the Mediterranean and Middle East, India and Central Asia. They're available in a wide variety of sizes and colors, from the tiny red lentils used in Indian cooking to the large green and brown varieties, as well as specialized varieties such as black beluga lentils and France's cherished, bright-green Puy lentils.
Soaked vs. Unsoaked
Lentils cook quickly without soaking. Most varieties cook in 20 to 30 minutes, with a few taking longer. That's roughly the same time it takes to cook rice, and many cultures have rice-and-lentil dishes that cook together. Although soaking isn't necessary, some cooks still consider it a useful preliminary. Old or insect-damaged lentils will float on top of the water, where they can be scooped out and discarded. Soaking also leaches away some of the complex sugars, or oligosaccharides, that cause flatulence. Lentils should be cooked in fresh water for the best results.
Red lentils are the smallest of the common varieties, with a delicate salmon or coral color that turns to gold as they're cooked. They have the briefest cooking time, taking as little as 15 minutes to soften and begin breaking down into a creamy puree. You can cook red lentils by placing them in a heavy heatproof bowl and covering them with 2 1/2 to 3 times their volume in boiling water. After sitting for 15 to 20 minutes, the lentils will be fully cooked. Drain any excess water through a fine mesh strainer, and either cool the lentils, puree them for dip or add them to the dish you're preparing.
Although the boiling-water technique won't fully cook other varieties of lentils, it can help make the tiny legumes even more versatile. For long-cooking varieties such as Puy or beluga lentils, the brief soak in boiling water will shorten their cooking time until it compares to ordinary lentils. After a soak in boiling water, conventional brown and green lentils need just a few minutes to finish cooking. You can add them to a soup or sauce shortly before serving, or add them to a pan with onions, garlic and other fresh vegetables and toss them as they cook. The moisture remaining on the lentils steams them until they're fully tender.