How to Make Red Lentil Soup

What is red lentil soup, and what should you expect it to taste and feel like?

Red lentil soup is a thick, smooth-leaning soup made from split red lentils simmered until they soften and break down. Expect a hearty texture that can be left rustic or blended, with a mild lentil flavor that takes well to onions, garlic, warm spices, herbs, and acid such as lemon. [1]

What makes red lentils different from other lentils?

Red lentils are usually split and skinned, so they cook quickly and fall apart instead of holding their shape. That breakdown naturally thickens soup without flour, cream, or long simmering. [1]

What basic equipment do you need?

You need a pot with a lid, a knife and cutting board, and a spoon or spatula. A blender is optional but useful if you want a smoother soup.

• Immersion blender: blends in the pot with less mess.
• Countertop blender: can make the smoothest texture, but hot liquids must be blended carefully in small batches.

What ingredients do you need for a reliable, everyday red lentil soup?

You need red lentils, aromatics, liquid, and seasoning. Everything else is adjustable.

Core ingredients

• Split red lentils
• Onion and garlic
• Stock or water
• Salt and pepper

Common additions that change the flavor without complicating the method

• Carrot and celery for sweetness and body
• Tomato paste for color and depth
• Ground cumin, coriander, turmeric, paprika, or curry-style blends
• Lemon juice or vinegar at the end for balance
• Greens stirred in at the end for a fuller bowl

How much liquid should you use for the texture you want?

Use about 3 parts liquid to 1 part dry red lentils for a thick soup, then thin as needed near the end. If your lentils are older or your simmer is very gentle, you may need a little more liquid.

Texture goal	Dry red lentils	Liquid to start
Very thick, stew-like	1 cup (200 g)	2 1/2 cups (600 ml)
Thick soup	1 cup (200 g)	3 cups (720 ml)
Lighter soup	1 cup (200 g)	3 1/2 cups (840 ml)

Do you need to rinse red lentils?

Yes, it is a good habit to rinse red lentils in a fine-mesh strainer until the water runs less cloudy. Rinsing removes surface starch and any small debris, which can reduce foaming and help the broth taste cleaner.

When should you add spices so they do not taste raw?

Add ground spices early, right after the aromatics soften, and stir them in for 30 to 60 seconds. This brief heating is sometimes called “blooming,” and it helps fat-soluble aromas release so the soup tastes more integrated.

How do you make red lentil soup step by step?

You make red lentil soup by sweating aromatics, simmering lentils until tender, then adjusting thickness and seasoning. Red lentils typically soften in about 15 to 25 minutes at a steady simmer. [2]

Recipe: Red Lentil Soup (Stovetop)

Yield: About 6 cups (1.4 L), serves 4 to 6
Time: 10 minutes prep, 30 minutes cook
Equipment: 4- to 6-quart (4- to 6-L) pot; optional blender

Ingredients (U.S. and Metric)

• 2 tablespoons olive oil (30 ml)
• 1 medium yellow onion, finely chopped (about 1 1/2 cups, 200 g)
• 2 medium carrots, diced small (about 1 cup, 120 g)
• 2 celery stalks, diced small (about 3/4 cup, 90 g)
• 3 garlic cloves, minced (about 1 tablespoon, 9 g)
• 2 tablespoons tomato paste (30 g), optional
• 1 teaspoon ground cumin (2 g)
• 1/2 teaspoon ground coriander (1 g), optional
• 1/4 teaspoon ground turmeric (0.5 g), optional
• 1 1/2 cups split red lentils, rinsed and drained (300 g)
• 6 cups low-sodium stock or water (1.4 L), plus more as needed
• 1 1/4 teaspoons kosher salt, plus more to taste (about 7 g)
• Black pepper, to taste
• 1 to 2 tablespoons lemon juice or mild vinegar (15 to 30 ml), to finish
• Optional finish: chopped parsley or cilantro (about 1/4 cup, 10 g)

Method

1. Soften the aromatics. Heat the oil over medium heat. Add onion, carrots, and celery with a pinch of salt. Cook, stirring occasionally, until the onion is translucent and the vegetables begin to soften, 6 to 8 minutes.
2. Add garlic and spices. Stir in garlic and cook 30 seconds. If using tomato paste, stir it in and cook 1 minute. Add cumin (and any other ground spices) and stir for 30 to 60 seconds.
3. Simmer the lentils. Add rinsed lentils, stock or water, salt, and a few grinds of pepper. Bring to a gentle boil, then reduce to a steady simmer (small bubbles breaking the surface). Partially cover and cook, stirring every few minutes, until lentils are very tender and breaking down, 15 to 25 minutes. [2]
4. Adjust texture. If the soup is thicker than you want, add hot water a little at a time. If it is thinner than you want, simmer uncovered for a few minutes. Red lentils thicken as they sit.
5. Blend if you want it smooth. For a rustic soup, stop here. For a smoother soup, blend with an immersion blender until the texture suits you, or carefully blend in a countertop blender in small batches (see safety note below).
6. Finish and season. Stir in lemon juice or vinegar. Taste and adjust salt and pepper. Add herbs if using.

Hot-blending safety note

Hot soup expands and releases steam. If using a countertop blender, work in small batches, keep the center cap off or vented, and cover the opening with a folded towel while holding the lid firmly. Start on low speed and increase gradually.

How do you keep red lentil soup from turning bland?

Season in layers and add a little acid at the end. Salt early so the lentils absorb it, then taste again after simmering and again after blending, since blending can mute seasoning.

If it still tastes flat, one of these usually helps:

• A small squeeze of lemon juice or a few drops of vinegar
• A pinch more salt
• Fresh black pepper
• A spoonful of tomato paste simmered in briefly (if not already used)

What are the most useful variations without changing the method?

Variations work best when they stay inside the same cooking steps.

• Creamier without dairy: blend thoroughly and add more olive oil, or add a small amount of coconut milk at the end if you like that flavor.
• With meat: brown ground meat or sliced sausage in the pot first, remove, then proceed; add it back near the end so it does not overcook.
• With greens: stir in chopped greens during the last 2 to 4 minutes so they wilt but stay green.
• More heat: add crushed red pepper with the spices, then adjust at the end.

How do you store and reheat red lentil soup safely?

Cool soup quickly and refrigerate it within 2 hours (within 1 hour if the room is very warm). For faster cooling, divide it into shallow containers or set the pot in an ice-water bath and stir. [3]

• Refrigerator: Store covered and use within 3 to 4 days.
• Freezer: Freeze in airtight containers with headspace for expansion; for best quality, use within about 3 months.
• Reheating: Reheat until steaming hot throughout. If the soup has thickened, loosen with water or stock as it heats.

Why does red lentil soup thicken so much overnight?

Red lentils continue to absorb liquid as they sit, and the starches that made the soup creamy at first will firm up when chilled. Plan to add a splash of water or stock when reheating, and then taste for salt again.

Endnotes

[1] bonappetit.com
[2] thekitchn.com
[3] extension.umn.edu
[4] foodandwine.com