How to Make Buttercream Thicker if it’s Too Runny

When it comes to piping buttercream on sugar cookies, cupcakes, or cakes, the question of how to make buttercream thick enough comes up often.

There are certain times that you will want a thick buttercream in order to pipe certain textures and heights. For example, a cupcake with a swirl of buttercream needs to be stiff enough to hold its height. Similarly, buttercream flowers need a stiff consistency to hold the petals.

Let’s discuss three ways to achieve a thicker buttercream frosting.

How to Make Buttercream Thicker Using Powdered Sugar

The easiest and most straightforward way to fix buttercream that is too runny is to simply add more powdered sugar. I always work with an American Buttercream recipe for this reason. American Buttercream has a higher sugar to fat ratio than a typical buttercream recipe.

For my American Buttercream recipe, I use anywhere from 3.5 to 4 parts sugar to butter. For example, three and a half cups of powdered sugar to one cup of butter. Using this much powdered sugar will make buttercream thicker than a typical two to one ratio.

If this buttercream is still too runny, look into the next two options for thickening it. Adding too much powdered sugar can result in a grainy buttercream. It can also become too sweet and inedible.

How to Make Buttercream Thicker Using Corn Starch

Powdered sugar is granulated white sugar pulverized with corn starch. Corn starch is commonly added to thicken dishes when cooking but doesn’t seem to be utilized as often in dessert.

If you want to further thicken buttercream frosting without making it sweeter, simply just add more corn starch.

You will want to start with a teaspoon at a time. It is best to use a sifter to add it to the buttercream to avoid lumpy frosting when mixing in a stand mixer. As always, don’t forget to use a paddle attachment in a stand mixer to avoid air bubbles.

If you do obtain unwanted air bubbles in your buttercream, check out my post on tips to fix airy buttercream.

Often times, I am decorating sugar cookies with several colors of buttercream and only one or a few colors need to be thicker. Once I have separated the colors into smaller bowls, I will then add more powdered sugar or corn starch to each individual bowl and stir it in with a fork.

How to Make Buttercream Thicker by Controlling the Temperature

If you are preparing buttercream frosting in a warmer climate, your butter may start to melt. As we know, melted butter is much thinner (and runnier, of course) than cold, solid butter.

One of the easiest ways to thicken buttercream is to simply place the buttercream into the refrigerator. If you have just mixed up your buttercream and you know your recipe is usually thick enough, cover the bowl with plastic wrap and place it in the fridge.

Come back to the buttercream after about thirty minutes, give it a stir, and see if it has become less runny.

An important note to keep in mind is that if you are using pastry bags, the heat from your hands will warm up the buttercream. So, if it’s a particularly hot day, place the cold buttercream directly into the pastry bag and allow your hand to warm it up as it is being piped.

Alternately, you can use two Ziplock bags filled with ice water and sandwich the pastry bags in between the ice water during piping breaks. I like to use this method rather than placing the bag in a cup of ice water because I don’t like having to dry the piping bag.

Technically, both methods do work very well though so it is up to your preference.

For more on how to keep buttercream cold, check out my blog post here.

Make sure to follow me on YouTube for more buttercream tips! Happy decorating!

Save the Tutorial for Fixing Runny Buttercream for Later

Use the image below to pin this tutorial for fixing runny buttercream to your baking board on Pinterest. Alternatively, use any of the social share icons on the top of the page to share it to your favorite social media site.