Can You Substitute Flour For Cornstarch? | Thickening Switch

Yes, you can substitute flour for cornstarch, but use twice as much all-purpose flour because cornstarch has about double the thickening power.

You’re in the middle of making gravy or a fruit pie, and the recipe calls for cornstarch. You open the pantry — and there’s none. But you do have all-purpose flour sitting right there.

That flour can probably save the dish, but not with a straight one-to-one swap. Cornstarch is pure starch and roughly twice as strong a thickener as flour, so you’ll need to adjust the amount and technique. This article covers the ratio, how to avoid lumps, and when flour works best as a substitute.

What Makes Cornstarch and Flour Different

Cornstarch is a refined starch extracted from corn kernels, while all-purpose flour is ground wheat that contains both starch and gluten protein. That extra protein in flour dilutes its thickening power — roughly half that of cornstarch per tablespoon.

The visual difference matters too. Cornstarch creates a glossy, translucent sheen in sauces and gravies. Flour produces an opaque, matte finish that works better for hearty dishes like gravy or cream sauce.

Cooking time also differs. Cornstarch thickens at a lower temperature and reaches full power quickly. Flour must be cooked longer to eliminate the raw, starchy taste and achieve its full thickening effect. And flour adds a slight flavor and pale color, whereas cornstarch is flavorless.

Why You Can’t Swap Flour in Equal Amounts

Many home cooks assume flour and cornstarch are interchangeable by volume. The catch is that cornstarch’s concentrated starch gives it far more thickening power, so a direct swap will leave your sauce thin.

• The 2:1 ratio. For every tablespoon of cornstarch, use two tablespoons of flour. This accounts for cornstarch’s roughly double thickening power.
• Make a slurry. Whisk the flour with a small amount of cold liquid before adding it to hot liquid. This prevents lumps from forming.
• Cook longer. Flour needs several minutes of simmering to lose its raw taste and reach full thickness.
• Add fat for smoother texture. A small pat of butter or drizzle of oil helps flour incorporate without turning pasty.
• Expect a different look. Sauces thickened with flour turn opaque and matte rather than glossy and clear.

These differences matter most for clear glazes, fruit pies, and stir-fry sauces where appearance is part of the dish. For hearty gravies and stews, flour is often the preferred thickener anyway.

Using Flour as a Substitute for Cornstarch

When you substitute flour for cornstarch, the ratio is just the starting point. You also need to account for cook time and the final appearance. The table below compares the two thickeners at a glance.

For gravies and meat-based sauces, flour is often the go-to thickener. The Illinois Extension guide on thickening agents notes that for a medium-thick sauce you generally need about twice the amount of flour compared to cornstarch — 2 tablespoons of flour per cup of liquid rather than 1 tablespoon of cornstarch.

How to Adjust Common Recipes

Every dish handles the swap a little differently. Here are some practical adjustments for four common uses.

1. Gravies. Use 2 tablespoons of flour per cup of liquid. Simmer for 3–5 minutes. The flour adds a richer, more savory flavor and helps the gravy cling to meat.
2. Fruit pie fillings. Expect an opaque, matte filling instead of a clear, glossy one. Cook the filling longer over medium heat to remove the raw flour taste.
3. Cream soups. Flour works well. Make a slurry with cold milk or broth first, then whisk it into the simmering soup. The result will be a slightly thicker, velvety texture.
4. Stir-fry sauces. Cornstarch is usually better for the glossy look this dish demands. If you use flour, reduce the liquid slightly because flour needs more time to thicken and may evaporate some water.

For gluten-free cooking, avoid all-purpose flour entirely. Cornstarch is naturally gluten-free and makes a suitable thickener on its own.

When Flour Is Not the Best Choice

Acidic ingredients can sabotage a flour-thickened sauce. If your recipe includes vinegar, lemon juice, or wine, flour may lose its thickening ability. Cornstarch holds up better in these situations.

You’ll also want cornstarch when appearance matters. Clear glazes for fruit tarts and glossy stir-fry sauces rely on cornstarch’s transparent finish. Flour will turn them cloudy and dull.

For gluten-free cooking, cornstarch is the clear winner — the Spruce Eats notes that cornstarch has roughly twice the thickening power of flour, so you can use half as much. This makes it a more efficient thickener for those avoiding gluten.

The Bottom Line

You can substitute flour for cornstarch in most recipes, but it’s not a perfect one-for-one trade. Use twice as much flour, make a slurry to avoid lumps, and cook it long enough to remove the raw flour taste. The final dish will have a matte, opaque appearance and a slightly different texture.

If you’re adapting a recipe for someone with celiac disease or a gluten sensitivity, a registered dietitian can help you select the right starch alternative. For everyday cooking, the 2:1 ratio is a reliable starting point, but don’t hesitate to adjust based on the look and feel you want.

Send us your feedbackTell us what you thought about this post

⚠Please use a real email you check. If it's fake or mistyped, your message won't reach us and we can't reply — wrong addresses are rejected automatically.

Name *Email *

Your comment *

Quick check — what is …? *

Send feedback