How to Thicken Split Pea and Ham Soup Without Clumps

Split pea and ham soup is a hearty soup made with dried split peas, ham, vegetables, and broth or water; it is often served hot as a meal. To thicken a batch that is too thin, first let the peas cook until tender, then simmer uncovered or blend part of the soup. The best method depends on whether you want a smooth or chunky texture.

What You’ll Need

A heavy pot or saucepan and a spoon for stirring
A ladle or measuring cup
Optional: an immersion blender, countertop blender, or potato masher
Optional thickener: 1 tablespoon (8 g) cornstarch and 1 tablespoon (15 ml) cold water per 4 cups (950 ml) of thin soup
Optional thickener: 1 tablespoon (14 g) butter and 1 tablespoon (8 g) all-purpose flour per 4 cups (950 ml) of soup

Step-by-Step

Check whether the peas are fully tender. Stir the soup and taste a pea. If it is still firm or chalky, keep simmering before adding a thickener. Split peas naturally break down and thicken the liquid as they cook. Add a little water or broth if the pot is getting too thick before the peas soften.
Simmer uncovered to reduce excess liquid. Bring the soup to a gentle simmer, not a hard boil, and leave the lid off. Stir every few minutes, scraping the bottom and corners so peas and ham do not stick. Check the consistency after 10 minutes; continue in 5-minute increments until it is as thick as you like. Reduction concentrates the existing flavor, so taste before adding salt.
Mash or blend some of the soup for a naturally thick texture. Take the pot off the heat. Use a potato masher to crush some peas against the side of the pot, or blend about 1 to 2 cups (240 to 475 ml) and stir it back in. For a chunkier soup, mash only a small portion. For a smoother result, use an immersion blender briefly, taking care around hot splashes. If using a countertop blender, work in small batches, do not fill it more than halfway, vent the lid according to its instructions, and cover the opening with a folded towel while blending.
Add a cornstarch slurry if you need a quick, neutral thickener. Whisk 1 tablespoon (8 g) cornstarch with 1 tablespoon (15 ml) cold water until smooth for each 4 cups (950 ml) of soup. Stir the soup to create a gentle movement, then slowly pour in the slurry. Simmer for 2 to 3 minutes, stirring, before deciding whether to add more. Do not sprinkle dry cornstarch directly into the pot; it is likely to form lumps.
Use a flour-and-butter paste for a fuller finish. Mash 1 tablespoon (14 g) softened butter with 1 tablespoon (8 g) flour until evenly combined for each 4 cups (950 ml) soup. Stir in small pieces, letting each dissolve before adding the next. Simmer gently for at least 5 minutes so the flour cooks through and loses its raw taste. This method adds a slight buttery flavor and a less translucent body than cornstarch.
Wait briefly, then adjust. Turn off the heat and let the soup stand for about 5 minutes; it often thickens as it cools slightly. Stir, then add hot broth or water a splash at a time if it has become too dense. If the soup contains leftover ham, reheat it to 165°F (74°C); USDA FSIS lists this as the safe minimum temperature for reheated leftovers, checked with a food thermometer.

Common Mistakes

Adding a thickener before the peas are tender: It can make the soup seem thicker while leaving the peas unpleasantly firm. Cook the peas until soft first.
Using too much starch at once: Excess cornstarch can make the soup gummy or gel-like. Start with the measured slurry, simmer, and reassess before adding another small amount.
Boiling hard or walking away: Thick soup can scorch quickly, especially at the bottom of the pot. Keep the heat low and stir frequently while reducing or after adding flour or starch.
Blending a full, sealed blender: Hot liquid expands and can force the lid off. Blend in small batches with a vented lid, or use an immersion blender carefully.
Salting before reducing: Simmering concentrates salt as well as flavor, and ham can already be salty. Wait until the final texture is set before adjusting seasoning.

Tips

For the simplest fix, use a combination of uncovered simmering and mashing; it preserves the soup’s original flavor and avoids introducing another ingredient.
Remove the ham bone or large pieces of ham before blending. Return any meat you want to keep in the soup after blending, and discard the bone.
Change one thing at a time. Reduce or mash first, then add a measured thickener only if the soup still needs more body.
If using flour or cornstarch, mix it separately before it reaches the soup. Cold liquid disperses the thickener more evenly than hot soup.
Cool leftovers promptly and refrigerate within 2 hours. Keep covered in the refrigerator for 3 to 4 days, or freeze for longer storage. Reheat leftovers to 165°F (74°C), stirring so the soup heats evenly.

Troubleshooting

The soup is still watery after simmering: Check that the peas are soft. If they are, mash or blend a portion; if not, continue gently cooking and add liquid only as needed to prevent sticking. Then use a small amount of slurry if further thickening is necessary.

It has lumps: If the lumps are from flour or cornstarch, whisk the soup gently or blend a portion until smooth. For the next addition, whisk the thickener with cold water first and pour it in gradually.

It has become too thick: Stir in hot water or broth, 2 tablespoons (30 ml) at a time, until it loosens. Taste again because broth may add salt.

The bottom is sticking or smells scorched: Immediately transfer the unburned soup to a clean pot without scraping the bottom. Lower the heat and stir more often. If a strong burnt flavor has spread through the soup, it may not be possible to remove it.

The texture is grainy: The peas may not have cooked long enough, or the soup may need more blending. Simmer until the peas are very tender, then mash or blend again. Do not use a thickener to disguise firm peas.

Frequently Asked Questions

What is the best way to thicken split pea and ham soup?
Let the peas cook until soft, then simmer uncovered and mash or blend some of them. These steps thicken the soup without changing its flavor much.

Can I thicken split pea soup with flour?
Yes. Combine flour with softened butter or whisk it with cold water before adding it. Simmer the soup for at least 5 minutes after adding flour so it cooks through.

Can I use instant mashed potatoes?
Yes, but add them sparingly because they can make the soup pasty. Stir in 1 tablespoon (about 6 g) at a time, wait a few minutes, and reassess before adding more.

Will split pea soup thicken as it cools?
Yes. Peas and starch continue to absorb liquid as the soup stands, so let it rest briefly before adding more thickener. Loosen leftovers with water or broth when reheating.

Can I thicken soup that is already cold?
Reheat it gently, stirring regularly, then use the same reduction, mashing, or slurry method. For food safety, heat leftovers to 165°F (74°C) and check with a thermometer.

How can I keep the soup from getting too thick in the refrigerator?
Store it covered and expect it to firm up as it chills. Reheat only the amount you need, stirring in hot water or broth a little at a time until it reaches the desired consistency.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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