How to Thicken Sauce in a Slow Cooker (5 Best Ways)

Published Categorized as Cooking Tips
How to Thicken Sauce in a Slow Cooker (5 Best Ways)Yash Maramangallam (via Pexels)

Slow cookers are a godsend! Just add the ingredients to the crockpot, close the lid tightly, set the heat and timer, and come back in a couple of hours. With a slow cooker at home, you can make easy and delicious meals for you and your family even on days when cooking is one of the thousand things on your to-do list.

Every now and then, though, you add a little more liquid (like water, broth, or wine) to a recipe than you should. Your food is about to come out watery.

What can you do?

When you add too much liquid to a slow-cooker recipe, your food can come out watery. If you’re in this situation right now, there are five things that you do to thicken your sauce, soup, or stew.

Here’s how to save the day.

#1. Leave the Lid Off, Letting Some of the Liquids Evaporate

To thicken sauces, soups, and stews in a slow cooker, leave the lid open and let the cooking liquid simmer gently until it has reduced to the desired thickness.

A slow cooker is like a Dutch oven with its own heating elements. When you turn it on, electric coils heat up under the cooking surface. The cooking surface reaches a temperature between 180°F and 320°F, which cooks the food low and slow till it’s done.

The food heats and releases steam, which gets trapped by the lid, creating condensation. The condensation creates a vacuum seal between the lid and the crock — and naturally retains the moisture in your food as it cooks.

Retaining the moisture in the food is the effect you’re looking for when you’ve added enough liquid. When you’ve added too much liquid to your recipe, you’re looking to take off the lid to let some of the moisture escape.

You’re essentially using the same principles as when making sauce in a pad or pot without a lid on the stovetop. The liquids come in contact with the heated cooking surface on the bottom and escape in the form of steam from the top.

If you decide to use this method to thicken your sauce, soup, or stew in the slow cooker, make sure you time it. Check on it every 10-15 minutes to make sure it doesn’t reduce down too much.

“Made a curry last night and put too much broth,” one Redditor says in a thread on the topic. “Left the lid off for the last hour and it came out nice and creamy.”

“Thanks for the help, guys,” the creator of the thread replied. “I left the lid off and it thickened up a bit more, so it turned out quite nicely.”

#2. Make a Roux and Add It to Your Sauce Mid-Cooking

If you ask professional chefs and seasoned cooks how best to thicken a sauce without letting it boil down, you almost always get the same advice: make a roux.

A roux is a mixture of equal parts flour and fat (usually butter) cooked in a pan over medium heat and used for thickening sauces. If your slow-cooker sauce, soup, or stew is coming out too watery, make a roux on the stovetop and add it to the slow cooker mid-cooking.

Heat a saucepan over medium heat. Add equal parts butter and all-purpose flour, stirring constantly, until the mixture becomes consistent and starts to brown. The longer you cook the roux, the darker it gets. A white roux tastes raw and floury; a dark roux tastes nutty and cooked.

Add the roux to your already simmering sauce in the slow cooker. Ideally, the next time you make the same recipe, you should make your roux first and use it to build the base of the rest of your sauce, soup, or stew.

My 2¢ for making roux that I want to share with you are:

  1. Never use high heat. It will burn your flour and produce an unpleasant and bitter-tasting roux.
  2. Stir constantly with a wooden spatula. Wooden spatulas have the right form and material to help you break up any lumps in the flour.

I know many home cooks get intimidated by the idea of making roux. Don’t. As long as you remember these two things, your roux is going to turn out fantastic.

#3. Enrich Your Sauce with Butter, Cream, Yogurt, or Egg Yolk

You can add a body to your sauce, soup, or stew by adding butter, cream, sour cream, yogurt, or egg yolks to it. This will not only thicken it but also add depth of aroma and flavor to it.

Pair the base to the ingredients well. Cream, sour cream, and yogurt go amazingly well with green sauces, soups, and stews, especially if green beans, peas, spinach, or stinging nettle is involved. They don’t pair that well with tomato- and wine-based sauces.

Butter, cream, and egg yolks (less so sour cream and yogurt) work well with vegetable stews and chicken soups. They add a nuttiness or creaminess to the white sauce.

Also, mind the heat. Yogurt and eggs will curdle at high-heat cooking. Only add them if you’re making sauces, soups, and stews on lower heat with your slow cooker.

#4. Puree 1/3 or 1/4 of the Sauce in a Blender

Thicken a sauce, soup, or stew with a blender. Pureé 1/3rd or 1/4th of its contents in an upright blender or turn the slow cooker temporarily off and use an immersion blender inside it, then resume cooking.

Use this method to make your chunky tomato sauce, vegetable soup, or hearty stew thicker and creamier. Upright blenders work best because they’re more powerful and give you more control over the pureeing process than an immersion blender. With an upright blender, it’s just easier to tell when you have the consistency you’re looking for.

The caveat to this method is that it won’t work well if you’ve already added meat to the slow cooker (unless you’re able to fish out the vegetables from the meats and transfer only them, along with enough liquid, to an upright blender). Who likes pureéd chicken or beef, really?

Blend the vegetables after they’ve cooked enough. I made the mistake to blend asparagus stew before the asparagus slices had softened up enough. I ended up with a pureé full of fibrous strands that made my stew inedible.

#5. Add Cornstarch

When cornstarch dissolves in water, you get a starchy and cloudy liquid that chefs call a slurry. As a rule of thumb, dissolve 1 tablespoon cornstarch in 1/2 cup water to thicken 3-4 cups of sauce. Add the slurry to your sauce as it simmers in the slow cooker.

Obviously, this technique only works when you’re making a meal in a slow cooker that’s coming out soupier than you want it to — and happen to have cornstarch lying around in your pantry. If my research into this topic showed one thing, it’s that not everyone is lucky enough to come across this collision of circumstance.

Nevertheless, cornstarch is always a good way to thicken a sauce, soup, or stew. Personally, I’d go for one of the other choices above as they add more depths of aroma and flavor to the food than cornstarch.

But that’s the beauty of home cooking: At the end of the day, it’s all about what you and your family like.

Editor’s note: After linking to this post in my email newsletter, one reader replied to tell me that potato flakes worked just as well as cornstarch. What a great idea! When you find yourself in this situation, feel free to substitute potato flakes for cornstarch.

Potato flakes, in case you are unfamiliar with the term, are flat chunks of dehydrated mashed potatoes. If they’re hard to find where you live, substitute with the same amount of instant mashed potatoes.

The Bottom Line

You don’t need to worry about your slow-cooker meal coming out soupy ever again. The next time you add a little too much broth, wine, or beer to your food, use any of the five methods above to thicken it to the consistency that you want.

Which one did you use? And how did it turn out? Have fun cooking and let me know in the comments below 😉 .

By Jim Stonos

When Jim isn't in the kitchen, he is usually spending time with family and friends, and working with the HCW editorial team to answer the questions he used to ask himself back when he was learning the ropes of cooking.

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