Flour is the default thickener in a lot of comfort food: the roux in a gravy, the dusting on stew meat, the paste stirred into a pot of soup. When you’re cooking low-carb, that’s usually the first thing to go. The good news is that you don’t need flour to get a sauce that coats a spoon.
The short answer: you can thicken without flour by removing water (reduction), adding body (cream cheese, cheese, pureed vegetables, egg yolks, or the natural gelatin from slow-cooked meat), or using a tiny amount of xanthan gum. Most of my recipes use a combination, and none of them need a roux.
What thickening actually does
Every thickener does one of two things: it takes water out, or it gives the water something to hold onto. Flour works the second way: its starch soaks up liquid and swells. But starch isn’t the only thing that can do that job. Fat, protein, fiber, and gelatin can all add body, and simply simmering a sauce down concentrates what’s already there.
Most thickeners are a shortcut. And there’s nothing wrong with using a shortcut when we’re short on time. When we’re not, there are other ways to thicken that don’t require us to add anything at all.
1. Reduction
The simplest thickener is time. Simmering a sauce uncovered lets water evaporate, so what’s left is thicker and more flavorful. It costs nothing and adds no carbs.
Watch out for: salt concentrates as the liquid cooks down, so season at the end.
See it in action: Coq au Vin, Hearty Beef Stew, and the filling of my French Onion Cottage Pie.
2. Gelatin from slow-cooked meat
Tough cuts like chuck roast are full of connective tissue. Cooked low and slow, that collagen breaks down into gelatin, which gives the cooking liquid a silky body on its own. It’s also why homemade stock made from bones is thicker than most store-bought broth.
See it in action: Tender Herby Pot Roast and Low-Carb Chicken Pot Pie Soup, which is built on homemade stock.
3. Heavy cream
Heavy cream thickens as it reduces, and it combines with the fat in the pan into a sauce that clings to whatever you’re serving. Lighter dairy like half-and-half adds creaminess but less body, so I stir it in at the end.
See it in action: Chicken in Bacon Cream Sauce and Creamy Garlicky Chicken and Veggie Soup.
4. Cream cheese and sour cream
Cream cheese is my go-to swap for a roux. Whisked or blended into a hot liquid, it melts into a smooth, thick base. Sour cream does the same with more tang.
See it in action: Zero Carb Country Sausage Gravy, Seafood Bisque, and Chicken Enchilada Casserole.
5. Cheese
Melted cheese adds body and flavor at the same time. Grated cheese melts more evenly than chunks, and stirring it in over low heat keeps it smooth.
See it in action: Broccoli Cheddar Soup, Cauliflower Cheese, and Smothered Cheese Omelet.
6. Pureed vegetables
Blend cooked vegetables back into a soup or sauce, and their fiber gives it body. Onions, broccoli stalks, cauliflower, pumpkin, and squash all work. Some, like pumpkin and squash, add a few carbs, but they also add flavor and nutrition that flour never would.
See it in action: Easy Shrimp Chowder (blended onion base), Hidden Veggie No-Bean Chili (pumpkin), and No-Roux Turkey Shepherd’s Pie (acorn squash).
7. Egg yolks
Egg yolks are a classic French thickener, often whisked with cream before going into a hot sauce. The risk is curdling. According to America’s Test Kitchen, what prevents clumps is diluting the egg proteins in liquid so they can’t link up into lumps as they heat. Whisk the yolks into some of the liquid first, add them to the pot, and stir constantly. Keep the sauce below a boil once the yolks are in.
8. Xanthan gum
Xanthan gum is the one specialty ingredient on this list, and a little goes a very long way. Bob’s Red Mill recommends 0.1% to 0.3% of the liquid’s weight for a thin sauce, which works out to about ¼ teaspoon or less per cup. It works hot or cold and thickens almost instantly.
Watch out for: clumping and texture. Sprinkle it in slowly while whisking (or blend it in), and start small. Even in small amounts, xanthan gum can give sauces a slightly slick, slimy texture, and too much makes them gummy. I don’t use it myself because I don’t love that texture, but it’s a perfectly valid approach if it works for your taste.
9. A little starch, used strategically
Low-carb isn’t no-carb. Sometimes a small amount of starch is the most practical answer, and spread across a whole pot, it adds very little per serving.
See it in action: half a packet of country gravy mix does the job in The Easiest Broccoli Cheese Soup. (Here’s how I define low-carb.)
What about budget and gluten-free?
If you look up low-carb or gluten-free thickeners, you’ll find a whole aisle of specialty products: guar gum, glucomannan, arrowroot, tapioca starch, almond and coconut flour, and gluten-free flour blends. Some of them are low-carb, some are gluten-free, and a lot of them aren’t budget-friendly or easy to find at a regular grocery store.
The good news is that almost everything on this list is readily available at any regular grocery store: cream, cheese, cream cheese, and vegetables. Reduction is free. That’s the Practical Plate approach: use what’s already in your cart before buying something special for one job.
Gluten-free, too: every thickening method on this list is naturally gluten-free, including xanthan gum. The exceptions are shortcuts like packaged gravy mix and canned cream soups, which often contain wheat flour. If you’re avoiding gluten, check the labels on any packaged ingredients.
Which thickener should you use?
| Thickener | Adds carbs? | Best for |
|---|---|---|
| Reduction | No | Braises, stews, pan sauces |
| Gelatin from meat | No | Pot roast, stock-based soups |
| Heavy cream | Barely | Pan sauces, creamy soups |
| Cream cheese / sour cream | A little | Gravy, bisque, casseroles |
| Cheese | Barely | Cheese soups, gratins |
| Pureed vegetables | Some, depending on the vegetable | Chowders, chili, blended soups |
| Egg yolks | No | Silky cream sauces |
| Xanthan gum | Barely, at these amounts | Gravy and sauces that need a quick fix |
| A little starch | Some, spread across the pot | When nothing else fits |
FAQ – Frequently Asked Questions
How do you thicken soup without flour?
Simmer it uncovered to reduce it, blend some of the cooked vegetables back in, or stir in cream cheese, heavy cream, or cheese at the end. A small amount of xanthan gum also works.
What is the best low-carb thickener for gravy?
Cream cheese and heavy cream, simmered down with the pan fat, make a rich gravy with no flour. For a thinner, more traditional gravy, a pinch of xanthan gum whisked in slowly is an option if you don’t mind the texture.
Why is my sauce still thin?
Usually it just needs more time. Simmer it uncovered so the water can evaporate. If it is a dairy-based sauce, reduce it before adding the dairy.
How much xanthan gum should I use?
Start with about 1/4 teaspoon or less per cup of liquid, sprinkled in while whisking. You can always add more, but too much makes sauces gummy.
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