How Long Do Green Lentils Take to Cook?

Green lentils boil in an average of 25-30 minutes in boiling water without soaking; soaking overnight brings that down to as little as 18-20 minutes. Their skin is tougher than red lentils, which is why the cooking time is noticeably longer. The right texture is reached when the lentils offer slight resistance when bitten but no longer taste raw — a point usually reached in the last few minutes of the range. Why does soaking shorten the cooking time? During soaking, the lentils absorb water and swell, which lets the surface conduct heat faster once it hits boiling water. Green lentils soaked overnight in lukewarm water soften 8-10 minutes earlier than unsoaked ones and cook more evenly throughout. Draining the soaking water and boiling in fresh water keeps the cooking time consistent and makes the lentils easier to digest. Why do green lentils take longer than red lentils? Red lentils are hulled and split, so they make contact with water much faster and reach a soft, almost mushy texture in 15-20 minutes. Green lentils retain their skins, so they can still be firm at that same point and hold together when pressed with a spoon. This difference is also why the two shouldn't be swapped one-for-one in a recipe without adjusting the time — doing so leaves you with either an undercooked or an overcooked result. When are lentils considered overcooked? A few extra minutes are enough for green lentils to lose their outer skins and edge toward a puree-like texture — desirable for soup, but not for salad. Keeping the water at a gentle simmer rather than a rolling boil helps the lentils stay whole for salads. Old lentils that have been sitting in storage for a long time commonly fail to soften in the standard time; in that case, extending the boiling by a few more minutes is reasonable. When should salt be added to the boiling water? Adding salt at the start of boiling can toughen the lentil skin and stretch out the cooking time, so it's safer to add it in the last few minutes. This timing also helps keep the 25-30 minute range above consistent. 1 bay leaf or half an onion added to the water gives the lentils a light aroma without affecting the timing. Why does adding tomato or tomato paste extend the time? Acidic ingredients like tomato, tomato paste or lemon juice added at the start of boiling can toughen the lentil skin and stretch the cooking time by 5-10 minutes. That's why these are usually added to lentil soup only after the lentils have fully softened. The same rule applies to other acidic ingredients like vinegar and yogurt; adding them in the last few minutes keeps both the timing and the texture on track. Should the foam that forms while boiling be skimmed off? Once lentils start boiling, a whitish foam forms on the surface; it comes from proteins dissolving out of the lentils and is best skimmed off with a ladle. Left alone, this layer can settle over the water and make it look cloudy. The foam usually forms within the first 5 minutes of boiling; after that point it doesn't come back, so checking once or twice early on is enough.