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How to Use Cornstarch to Thicken

Do you use cornstarch to thicken sauces and gravy when cooking? Wondering how it works and what is the best method to add it in? Here’s how to thicken soups, and the perfect cornstarch to water ratio you will need for each dish to be perfect.


I use cornstarch to thicken sauces all of the time! It took a bit to learn the best method so it didn’t clump up and here to share my cooking basics tips with you. (affiliate links present)

How to Use Cornstarch

This powder looks quite similar to flour, but it’s not. Lighter in nature I prefer it over the other and buy it in bulk I use it so often. A little goes a long way for sure with this stuff. This is my favorite brand in a reusable container that closes well.

In the past my mom used to make a roux this way. Pouring flour into a pan on the stovetop after sauteeing vegetables it created a thick paste. This was used to thicken gravy at Thanksgiving. It worked okay…..


Cornstarch Soup Thickener

I will admit it wasn’t always smooth and you’d likely get a clump of thickener in your bite, it wasn’t pretty.

Now that I create my own easy Instant Pot recipes, and gravy for the holidays I have a different method. It works much better and is so simple to do. Instead of adding your thickener in your dish dry, it’s important to whisk it with some liquid first.

Then when you add it into your recipe and allow it to bubble a bit, your mushroom gravy or sauce(s) will become thicker without those pesky lumps! I mean you want thick like comfort food for things like slow cooker meatballs and gravy type dishes so….

mushroom gravy recipe

How to Use Cornstarch to Thicken

Keep in mind that 1 Tbsp. of corn starch is equal to 2 Tablespoons flour. If you’re used to using the latter this is a good gage to use. Start small. You can always add more cornstarch slurry later.

  • In a small bowl or ramekin add the cornstarch starting with 1 – 2 Tablespoons of cornstarch at the beginning.
  • Pour in twice as much cold water as thickening powder you’ve added. (i.e. 1 Tbsp cornstarch + 2 Tbsp. water)
    • I have also just used some of the hot liquid from my pot instead of using cold water. I’ve done this in cases where I didn’t want to add any more liquid into my dish. It works just as well as long as you whisk it well.

What is the cornstarch to water ratio for thickening?

A common ratio is 1 part cornstarch to 2 parts cold water. For example, to make a slurry, you would mix 1 tablespoon of cornstarch with 2 tablespoons of water. Stir this mixture into your hot liquid, and heat it until it thickens. Adjust the amount based on how thick you want the final product to be, but always maintain that 1:2 ratio for best results.

cornstarch thickener
Can I substitute cornstarch for tapioca starch?

You can! The measurements are that 2 Tablespoons of tapioca flour is equal to only 1 tablespoon of cornstarch. Use this as a more readily available substitute if you wish.

How much cornstarch do you use to thicken?

It depends but typically 1-3 Tbsp. is plenty to start to thicken soups and sauces. Add thickening agent to cup of liquid and whisk until smooth before adding. Stirring constantly as it boils so it stays smooth.

Then use a fork to whisk the slurry together so it is nice and smooth. It won’t necessarily look thick in of itself but will do the job once you add it into your recipe.

how to use cornstarch

How to Use Cornstarch to Thicken Soup

Ideally you want your sauce or soup to be at a slow rolling boil when you add this. Keep it at that temperature and stir slowly and consistently to keep your mixture nice and smooth.

If after it’s cooked this way for about 2 minutes it isn’t as thick as you’d like it to be then follow the same steps again. Add 1 more Tbsp with liquid until smooth, add in and stir.

Remember!! As your dish cools down it will get even thicker so do not add too much. Cornstarch to thicken is the best!!

arm roast recipe

The beauty of a rich hearty sauce is that it takes your oven baked pork chops or Ninja Foodi recipe from good to OH MY out of this world. Pour it on top of your protein and mashed potatoes for the best meal ever.

Especially when it comes to making a large chunk of meat or roast, you really do need a thick sauce poured on top to keep it moist. If you follow this easy tip you can create wonderful sauces or soups of all kinds.

How long does cornstarch take to thicken?

the full thickening process can take a few minutes, depending on factors such as the temperature of the liquid, the amount of cornstarch used, and the desired consistency. Generally, after adding cornstarch to a liquid and bringing it to a simmer, you’ll start to notice thickening within a minute or two.

Time needed: 5 minutes

Cornstarch to Thicken

  1. Whisk

    In a small bowl whisk together 1 or 2 Tbsp of corn starch with twice as much cold water. I have also used some hot liquid from my broth as my liquid thickener.

    Do this until your roux is very smooth.

  2. Thicken

    Pour this into your sauce that is at a rolling boil and consistently stir. It will become thicker in about 2 minutes. If you want it thicker follow the same process with 1 more Tbsp.

  3. Tips

    Remember it will continue thickening as it cools so do not add too much. Serve your soup or gravy immediately for best results. Store powder in an airtight container.

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Catherine Hart

Monday 29th of April 2024

I learned this from my Southern mother: Put some of your prepared liquid (broth, soup, etc.) in a 1-2 cup jar, add 1 T corn starch and shake! It mixes perfectly every time and you don't need to use water. (Though that little bit wouldn't weaken the flavor.)


Friday 21st of July 2023

So many ads on this site that convolute each page, after a short time, with frustration growing, I was better off changing sites. It’s too bad, this site seems to have useful information as well as recipes. Maybe better on desktop, not a phone


Thursday 14th of September 2023

@Pat, Definitely better on a desktop. There is enough room to see around the ads unlike on a phone screen.

The Typical Mom

Friday 21st of July 2023

Ads allows bloggers to offer our recipes for free, otherwise we would have to charge everyone a fee to access. Websites are VERY expensive to maintain

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