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Quick Summary tl;dr
Flour is the default thickener in most kitchens, but it’s not essential — and it’s often the part that doesn’t fit a low-carb approach.
Start with the simplest fixes first: reduce the sauce, finish with butter, or blend part of the vegetables back in.
For sauces that need more structure, egg yolks, cream, yogurt, cream cheese, and even mushrooms can do a lot without any starch.
If you prefer a powdered thickener, use small amounts and add carefully: konjac and xanthan are powerful and clump easily if dumped in.
Arrowroot, cornstarch, and potato starch work well, but they’re starch — so the carbs add up fast, especially in soups and gravies.
For years, thickening a sauce just meant adding flour. That’s how most of us learned to cook. If a gravy was thin, you reached for it without thinking.
But once you start building meals around protein, vegetables, and healthy fats — and paying attention to how the science around dietary guidelines has evolved, like in these updated real food guidelines, flour stops feeling like the automatic answer.
And honestly, it never needed to be.
If you’ve ever made a stew that tasted perfect but needed more body, you’ve probably wondered what to use instead. The good news is that you have plenty of options. Some don’t require anything extra at all. Others use simple low-carb ingredients that work reliably once you understand how they behave.
In this guide, I’ll walk you through the thickening methods I actually use, when each one works best, and what to watch out for so you get the texture you want without relying on refined starches.
1. Reduction (Start Here First)
Before you reach for any thickener, try this: just let the sauce cook a little longer.
Reduction is the simplest way to thicken anything. As the liquid simmers, water evaporates and the sauce naturally becomes thicker and more concentrated. You’re not adding anything — you’re just removing excess liquid. This works especially well for pan sauces, gravies, and braises.
If your stew already has tender meat and vegetables, don’t keep boiling the whole pot. Ladle some of the liquid into a smaller saucepan and reduce it separately. That way you thicken the sauce without overcooking everything else.
Salt at the end, not the beginning. As the liquid reduces, the salt becomes more concentrated, and it’s easy to overshoot.
You can also build thickness with fat. After cooking steak or chicken in a pan, deglaze with a splash of wine or lemon juice, scrape up the browned bits, then whisk in a tablespoon or two of cold butter. It thickens the sauce naturally and gives it a smooth, glossy finish — no starch needed.
2. Pureed Vegetables (The Easiest “Hidden” Thickener)
If you’re already cooking vegetables in your soup or stew, you’re halfway there. Blending part of the vegetables back into the sauce is one of the most natural ways to thicken it. You’re not adding anything new — just changing the texture of what’s already in the pot.
Onions, garlic, zucchini, cauliflower, broccoli, and bell peppers all work well. Once they’re soft, scoop out a cup or two along with some cooking liquid, blend until smooth, and stir it back in. The sauce thickens, and the flavor stays cohesive.
This method works especially well in hearty dishes like stews. Recipes such as Cozy Fall Beef Stew, Red Wine Pork Stew, and Broccoli Cheese Soup use this approach to build body without flour.
You can also use more concentrated vegetable bases when they fit the recipe. Tomato paste naturally thickens and deepens flavor. Pumpkin or butternut squash purée can add body to fall-inspired soups. Just keep carbs in mind with sweeter vegetables — they work well, but they’re not always the lowest-carb option.
The key is balance. You don’t need to blend the entire pot. Often, a small portion is enough to give the whole dish a thicker, more satisfying texture.
3. Dried Mushrooms (For Depth and Natural Body)
Mushrooms are underrated when it comes to thickening. They don’t just add flavor — they add body. When blended into a sauce, mushrooms create a subtle thickness that works very well in gravies and meat-based stews.
Dried mushrooms are especially useful because their flavor is more concentrated. Porcini are a great option. Just soak them in boiling water for about 20–30 minutes, then simmer for at least 10 minutes before blending. You can use both the softened mushrooms and a bit of the soaking liquid for even more depth.
Fresh mushrooms work too, especially if you sauté them first to cook off excess moisture before blending.
This method is ideal when you want a thicker texture without dairy or added fats. It’s the approach used in this gluten-free Keto Gravy, where mushrooms and aromatics create thickness naturally. Dried mushrooms are also the main ingredient in this Cream of Mushroom Soup, where they add both thickness and flavor.
It won’t give you a glossy, starch-like finish — but that’s often a good thing. The result feels more like real food and less like something held together by filler.
4. Egg Yolks (For Creamy, Classic Sauces)
Egg yolks are one of the most effective ways to thicken a sauce without using starch. They work especially well in soups, stews, and pan sauces where you want more body without adding flour or gums. Instead of creating a glossy, starchy finish, they help the sauce hold together and give it a more structured texture.
The only thing to watch is temperature. If you add egg yolks straight into a very hot liquid, they will scramble. The solution is to temper them. Whisk the yolks with a little cold water, stock, or cream first, then slowly add some of the hot cooking liquid while whisking continuously. Once the mixture has warmed, pour it back into the pot over low heat and stir gently until it thickens. There’s no need to boil it; gentle heat is enough.
I’ve used this method many times in my recipes, including those in my Keto Slow Cooker & One-Pot Meals cookbook, and it becomes second nature once you’ve tried it a few times. You can also see it in action in recipes like Instant Pot Beef Stew, Pork & Kohlrabi Stew, and even these Scalloped "Potatoes" where egg yolks help achieve the right consistency.
✅ Tip: Avoid aluminum pans when thickening with egg yolks. Aluminum can react with the eggs and affect both the color and taste of the sauce. Stainless steel, enamel-coated cast iron, or glass will keep everything neutral.
5. Almond Flour or Coconut Flour
Nut and seed flours can thicken sauces, but they need to be used carefully. They don’t behave like wheat flour, and treating them the same way usually leads to disappointment.
Almond flour can add some body to stews or gravies, especially when whisked into fat first to prevent clumping. It works better in rustic dishes where a slightly textured finish isn’t a problem. It will not create a smooth, classic roux-style sauce, so it helps to know what they can and can’t do.
Coconut flour is much more absorbent. A very small amount can noticeably thicken a sauce, which means it’s easy to overdo it. If you decide to use it, add it gradually and whisk thoroughly. Let the sauce sit for a minute before adding more, since coconut flour continues absorbing liquid as it rests.
Neither of these flours is ideal for making a traditional roux, and they won’t replicate the texture of wheat flour. However, in the right dish and in small amounts, they can help add structure without adding many carbs.
6. Ground Flax Seed
Ground flaxseed can thicken sauces by forming a gel when mixed with liquid. It’s often used as an egg substitute in baking, but it also works in soups and stews when you need a small boost in thickness.
To use it, mix a small amount of flax meal with water first and let it sit for a minute until it thickens. Then stir it into your dish and allow it to simmer briefly. It doesn’t take much, so start small and adjust if needed.
Flax has a noticeable flavor, especially if you use too much, and it can slightly darken the color of lighter sauces. It works best in heartier dishes where those changes won’t stand out. Used carefully, it’s a simple, fiber-based option that doesn’t rely on refined starches.
7. Chia Seeds
Chia seeds thicken by absorbing liquid and swelling. They can be useful when you want more body without using starch or dairy.
Whole chia seeds work well in recipes like sugar-free jam, where the texture is meant to be slightly seeded. For sauces and gravies, ground chia blends in better and gives a more even result.
Start with a small amount and give it time. Chia continues absorbing liquid as it sits, so a sauce that looks thin at first may thicken after a few minutes. Adding too much can make the texture heavy or slightly grainy, especially in smoother sauces.
This method works best in dishes where a perfectly smooth finish isn’t necessary. Used in moderation, it’s a simple way to add thickness while keeping carbs low.
8. Dairy: Cheese, Cream, and Yogurt
Dairy is one of the simplest ways to thicken a sauce without using starch. It works because fat and protein naturally add structure, especially when gently reduced.
Heavy cream is the most straightforward option. Let it simmer for a few minutes and it will thicken on its own. There’s no need to add anything else. This works well in pan sauces, chicken dishes, and creamy soups where you want more body but don’t want to change the flavor too much.
Sour cream and unsweetened yogurt also work, but they need a bit more care. Add them at the end over low heat and stir gradually to prevent curdling. They’re especially useful in stews or sauces that already have some acidity. Recipes like Breton Chicken and Creamy Tarragon Chicken use this approach successfully.
Cream cheese thickens more quickly and gives a firmer texture than cream or yogurt. A small amount goes a long way. It works especially well in vegetable dishes, such as Salmon with Creamy Spinach & Hollandaise Sauce and Marry Me Chicken. When combined with shredded cheese, it also forms the base of a thicker cheese sauce like this Cheese Sauce.
The key with dairy is heat control. Keep it gentle, avoid boiling once added, and let it thicken gradually rather than forcing it.
9. Nut & Seed Butter
Nut and seed butters are one of the easiest ways to thicken certain sauces — if the flavor makes sense in the dish. I don’t use them everywhere, but in the right recipe, they work extremely well.
They’re especially useful in curries, stews, and stir-fries where a slightly thicker base is expected. Almond or macadamia butter blend in more quietly. Tahini and sunflower seed butter are great if you’re avoiding nuts. Peanut butter works well in recipes like Keto Pad Thai, where that flavor already belongs.
The important thing is restraint. These are concentrated ingredients. Start small, stir well, and let the sauce simmer before deciding whether it needs more. Adding too much too quickly can overpower everything else.
This isn’t a universal thickener, but when it fits the dish, it’s reliable and straightforward.
10. Gelatin Powder or Agar Powder
Gelatin is my go-to when I need structure in a sauce or dessert without using starch. It works differently from flour or gums. Instead of thickening as it boils, it firms up as it cools, which makes it especially useful in custards, chilled desserts, and certain sauces.
If you’re replacing something like cornstarch in a custard, gelatin does the job cleanly. That’s exactly how the Keto Vanilla Custard works — no starch needed. The texture sets properly once cooled, and you’re not left trying to mimic flour.
The key is blooming it first. Sprinkle gelatin over cold water, let it sit for a few minutes, then dissolve it gently into warm liquid. Don’t boil it aggressively, or it can lose some of its setting strength.
Agar powder works in a similar way and is suitable if you avoid animal products, but it behaves a little differently. It sets more firmly and needs to be simmered briefly to activate. I find it less forgiving than gelatin, so it helps to measure carefully.
Neither of these is something you throw into a random pan sauce at the last minute. They’re more deliberate tools. But when you need a proper set without starch, they’re reliable.
✅ Tip for Gelatin & Agar Conversions: If a recipe calls for 1 teaspoon (about 3 g) powdered gelatin, here’s how to substitute.
- 1 teaspoon powdered gelatin ≈ 1 1/2 standard gelatin sheets (leaves)
- 1 teaspoon powdered gelatin ≈ 1 teaspoon agar powder
- 1 teaspoon powdered gelatin ≈ 1 tablespoon agar flakes
Keep in mind that agar sets more firmly than gelatin, and the texture will be slightly different. Agar also needs to be simmered briefly to activate, while gelatin should be bloomed in cold liquid first.
11. Psyllium Husk
Psyllium husk thickens quickly and doesn’t require much to work. It absorbs liquid fast and forms a gel when mixed with liquid, which makes it useful in soups, stews, and even some sauces.
The most important thing here is quantity. A small amount goes a long way. Start with a pinch to 1/4 teaspoon, stir well, and give it a minute before deciding whether to add more. If you add too much too quickly, the texture can turn dense and slightly gummy.
Powdered psyllium blends more evenly than whole husk and is easier to control in sauces. It’s fairly neutral in taste, but in larger amounts it can slightly darken the dish and change the texture more than you intended.
I use psyllium more often in baking, but it can be helpful in savory recipes when you need quick thickening and don’t want to rely on starches or gums. It’s not something I use for delicate sauces, but in heartier dishes it does the job.
12. Xanthan Gum and Other Vegetable Gums
Xanthan gum is probably the most commonly used low-carb thickener, but it’s not always my first choice. It works quickly and requires very little, but it behaves differently from traditional starches.
For most sauces, 1/8 to 1/4 teaspoon is enough. Any more than that can turn the texture overly thick or slightly sticky. The safest way to use it is to sprinkle it gently over the surface while whisking or blending. Using a fine-mesh sieve helps distribute it evenly. If you dump it into one spot, it will clump.
Xanthan creates a smooth finish that works well in dishes like this Chicken and Mushroom Soup or Chicken Paprikash Stew, where you want a thicker consistency without using flour. It’s also useful in desserts such as Low-Carb Rice Pudding, where a small amount helps stabilize the mixture.
The main mistake people make is using too much. Xanthan can create a slightly elastic texture if overused, which isn’t always pleasant. Guar gum and similar vegetable gums behave in a comparable way. They’re effective, but they require restraint.
I use them when I need quick thickening and a consistent finish. They’re tools, not default ingredients.
13. Konjac Flour (aka Glucomannan Powder)
Konjac flour, also known as glucomannan, is one of the strongest low-carb thickeners available. A very small amount makes a noticeable difference.
In most cases, 1/4 to 1/2 teaspoon is enough for an entire pot of sauce. The challenge isn’t getting it to thicken — it’s preventing clumps.
You can mix it with a little cold water first to create a slurry, or sift it lightly over the surface while whisking continuously. Both methods help it disperse evenly. If added carelessly, it can form small gel-like lumps that are difficult to smooth out.
Konjac works particularly well in sauces where you want a clean, smooth result without adding flavor. It’s useful in recipes like Teriyaki Sauce and Spicy Sweet Chili Sauce, where traditional starch would normally be used. It can even help with texture in desserts such as Lemon Bars, when used carefully.
Start small, stir thoroughly, and allow it a minute to fully activate before deciding whether to add more. Once you’ve worked with it a few times, it becomes predictable and easy to control.
Starch-Based Thickeners (And Why They Don’t Fit Strict Keto)
Arrowroot, cornstarch, and potato starch all work very well as thickeners. That’s not the issue. The issue is that they’re almost pure starch.
One tablespoon contains roughly 7 to 8 grams of carbs. That may not sound like much, but in a low-carb or ketogenic diet, it adds up quickly — especially in dishes like gravy or soup where portion sizes aren’t tiny.
If you’re strictly keto or managing blood sugar closely, these aren’t practical options. They raise blood sugar quickly and don’t offer much beyond thickening.
That said, context matters. If a recipe uses one tablespoon for an entire large dish and you divide it into several servings, the carb impact per portion may be minimal. Some people are comfortable with that. Others aren’t. It depends on your approach and goals.
The important thing is clarity. These thickeners are effective, but they are not low-carb.
What About Roux?
Traditional roux is made by cooking equal parts fat and flour together. The flour is what thickens the sauce, which means a true roux depends on starch.
Almond flour and coconut flour won’t create the same effect. They can toast in fat, but they don’t form the kind of thickening network that wheat flour does. If you try to force them into a classic roux role, the texture usually ends up grainy rather than smooth.
If you’re not strictly low-carb and want a starch-based alternative, arrowroot can be used in place of flour. Melt your fat first, whisk in an equal amount of arrowroot, and cook it gently for a minute or two while stirring. It won’t brown quite like traditional roux, but it will thicken once liquid is added.
That said, arrowroot is still starch. It behaves like one because it is one. If you’re keeping carbs very low, it’s usually simpler to skip roux entirely and use reduction, egg yolks, dairy, or one of the other methods above.
Final Thoughts
Flour became the default thickener because it works and it’s familiar. That doesn’t mean it’s necessary.
If you’re eating low-carb or simply building meals around whole foods, there are plenty of ways to get the texture you want without relying on refined starches. In many cases, the best solution isn’t a substitute at all — it’s a different approach. Reduction, egg yolks, dairy, or even blending vegetables often create a better result than trying to replicate a traditional flour-based sauce.
The key is understanding what each option actually does. Some thicken by reducing liquid. Some bind. Some set as they cool. Once you see how they behave, choosing the right one becomes straightforward.
You don’t need to memorize all of them. Just know you have options — and flour is only one of them.
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