How to Thicken Frosting

Starting with Quick Fixes

What went wrong: it could be something totally out of your control. If your frosting is too runny, it might just be humid and hot outside, so your ingredients are melting. Or, maybe you accidentally added too many liquid ingredients. Whatever the case is, don’t fret! Liquid frosting can be saved and made into a thick, creamy mixture to use on your baked goods. Frosting also tends to separate when it’s been stored.

Keep mixing. It could just be that your frosting ingredients haven’t fully incorporated yet, or they might have separated during storage. Grab a whisk or a hand mixer and try stirring up your frosting again for 3 to 4 minutes to see if it thickens up. Since this method is so easy, you can always try it first to see if it helps.

Put your frosting in the fridge if it’s too warm. Most frosting is made primarily of oil or fat, so when it gets too warm, it can start to melt. If you’ve left your frosting out at room temperature or warmer, try putting it in the fridge for 30 minutes to see if it thickens. When you take the frosting out of the fridge, use a hand mixer to beat it again until it’s smooth. This method works the best on frosting with a butter base or whip cream frosting. If you know your frosting hasn’t gotten too warm, you can skip this method.

Cook hot frosting for more time. If a stovetop frosting still seems a little too liquidy, you might be able to reduce some of that liquid by extending the cooking time slightly. Turn your pan on medium heat and whisk your frosting constantly to avoid burning or browning. This technique works best for frosting that has already been heated up during the cooking process, like boiled-milk frosting. Note, however, that you should exercise caution while trying this technique. If you cook frosting too long, it may burn or break down. Stir the frosting frequently as it cooks, and if it does not appear to start thickening after a few additional minutes, remove it from the heat and try a different tactic.

Adding Dry Thickening Ingredients

Add more powdered sugar. Most frostings contain powdered sugar, or icing sugar, and the most common way to thicken a runny frosting is by gradually mixing in a bit more powdered sugar to offset the liquid ingredients. Sprinkle in 1 to 2 tbsp (15 to 30 mL) of powdered sugar at a time, then stir it in and check the consistency. If you add too much at once, the frosting will become too sweet and may become too thick. If this happens, you will need to add more liquid to balance it out, and the consistency problem may only continue from there. Powdered sugar contains cornstarch. Starches absorb liquid, and the cornstarch present in powdered sugar prevents the powdered sugar from caking. Adding powdered sugar works best on cream cheese frosting.

Mix in a bit of meringue powder alongside the powdered sugar. To cut down on the sweetness of powdered sugar, you can add meringue powder, as well. It will thicken your frosting without contributing any sweetness of its own. Typically, if you are adding more than 1/2 cup (125 ml) of powdered sugar to thicken a runny royal icing recipe, you should also add 1 to 2 tsp (5 to 10 ml) of meringue powder. This is especially true if the recipe already contains meringue powder. Meringue powder is made from dried egg whites, sugar, and gum. The sugar can absorb some of the liquid and the gum is a natural thickener. If used in excess, however, you might end up with a frosting that is too heavy or stringy.

Use tapioca, cornstarch, or arrowroot starch. Dry starches like these absorb liquid and are a great way to thicken frosting without altering the taste of the frosting. Add roughly 1 tbsp (15 ml) of starch to your frosting. Heat the frosting over low heat, if it can withstand higher temperatures, while stirring the starch in. Remove from the stove as soon as the frosting begins to thicken. Cornstarch is probably the most popular starch to use in frostings since it has low gloss, little flavor, and works well with dairy. It congeals when exposed to low temperatures, though, so it is not ideal for use with frostings that need to remain refrigerated. Arrowroot produces a high gloss and works better with acidic liquids. It tends to become slimy when added to dairy, but if your frosting contains dairy products with a higher acidity, like sour cream or buttermilk, arrowroot is a good choice. It also thickens at a fairly low temperature, making it suitable for frostings that will need to remain cool. Tapioca also has a high gloss, but it stands up well to cold temperatures and thickens at a fairly low temperature, as well, making it a better option if you have a frosting that will need to remain cold.

Add more cocoa powder if you’re making chocolate frosting. While this is not an option for vanilla, cream cheese, or other non-chocolate frostings, the addition of more cocoa powder is worth trying if you are making a chocolate frosting. Add more cocoa powder into the frosting 1 to 2 tsp (5 to 10 ml) at a time. Otherwise, you may end up with frosting that is too thick or too potent. Since cocoa powder is also fairly bitter on its own, too much can also cause the frosting to become bitter. Cocoa powder is a starch thickener, as well, but does not need to be cooked in order to thicken liquid. As a result, cocoa powder is a better addition than melted chocolate when you are trying to thicken your frosting. Unsweetened cocoa has more thickening power than bittersweet chocolate. The former contains more starches than the latter.

Mix in some gelatin to avoid flavoring your frosting. If you don’t want to add any sweetness to your frosting, pour a flavorless gelatin packet into warm or cold water. When the gelatin has dissolved, pour it bit by bit into your frosting, stirring continuously, until your mixture thickens. Try to use gelatin in cold water. That way, you won’t have to wait for it to cool down before you add it in.

Add in some shredded coconut to enhance the flavor. If you’re already making coconut icing, you can add more in to thicken up your mixture. Add at least 6 g (1/4 cup) of shredded coconut to your frosting, then fold it in with a spatula. You can buy coconut pre-shredded from the grocery store, or you can shred it yourself with a cheese grater.

Use flour for cooked frostings. If you are making warm frosting on your stovetop, you can try thickening a runny frosting with a bit of flour. Sprinkle 1 tsp to 1 Tbsp (5 ml to 15 ml) of flour into the frosting and stir over low heat on the stove until it begins to thicken. Remove it from the stovetop and keep stirring until the frosting cools down. Do not use flour in cold frosting recipes, however. Flour has a distinctive taste when eaten raw, and the only way to get rid of this taste is by cooking it out. Flour will not reach its maximum thickening capability if it is not heated. Remove the frosting from the heat as soon as it begins to thicken. Cooking flour in for too long can cause the frosting to become thin and runny again.

Adding Moist Thickening Ingredients

Try softened cream cheese. If your frosting is too sweet as well as being too runny, you can try adding cream cheese to it as a way to thicken the consistency and add a contrasting tanginess to the existing sweetness. Add about 1 oz (30 ml) of cream cheese to your frosting and blend it in well. This works best with frostings that already contain cream cheese or those that could benefit from less sweetness.

Mix in more butter or shortening. For frostings that use butter or shortening, using more of either ingredient can help thicken frosting that is a little too runny. Add 1 tbsp (15 mL) or so at a time to prevent distorting the taste and consistency too drastically. Note that adding butter to the frosting may not seem to help immediately. As the frosting heats up from being mixed, the butter will melt, making the consistency thinner. Refrigerate butter-based frostings to get an accurate picture of how thick the frosting really is.

Consider mixing in a dash of heavy cream. For frostings that can stand to be beaten and chilled, heavy cream is another way you can thicken the consistency without making the taste too sweet. Add about 1/4 cup (60 ml) heavy cream to the frosting and beat it well to combine your ingredients. Cream will provide a thick, rich texture. This works best if you plan on heating or whipping your frosting after you add the cream. Heating cream causes it to reduce down, becoming thicker as a result. Whipping cream causes it to fluff up, which also makes it thicker and causes the frosting to become lighter in texture.

Use marshmallow fluff if you’re making marshmallow buttercream. Marshmallow fluff is the perfect blend between sticky and fluffy, so it can help bind your ingredients together. If you’ve already put some in your frosting, add 1 to 2 tbsp (15 to 30 mL) more, then fold it in with a spatula. Marshmallow fluff is super sweet, so you should only add more if you don’t mind an intense flavor.

Thickening Ganache

Measure your wet ingredients carefully. Even a teaspoon too much heavy cream can make your ganache runny and inconsistent. As you put together your frosting, use measuring cups carefully to avoid any mistakes. It’s pretty tough to balance out your ingredients if you’ve added too much of something. Better safe than sorry!

Use heavy cream or whipping cream. While most recipes call for this, it’s easy to think that you can substitute them for regular milk. However, normal cow’s milk doesn't have enough fat to thicken ganache, so you might end up with watered down frosting instead of a thick and creamy one. You can find heavy cream and whipping cream in the dairy aisle of your grocery store.

Find a recipe based on the chocolate you’re using. White chocolate is different from milk chocolate, and milk chocolate is different from dark chocolate. Make sure you’re reading off a recipe that lines up with what chocolate you’re using to avoid a runny outcome. White chocolate will usually make your ganache much thinner than dark chocolate.

Throw in a handful of chopped chocolate if your ganache is too thin. While your ganache is still warm, chop up some more chocolate (the same kind that you already used) and throw it into the bowl. Stir the chocolate in with a spatula to let it melt and combine to thicken up your mixture. If you do this after your ganache is cold, your chocolate won’t combine and you’ll end up with lumps in your ganache. If you need to heat your ganache back up, put it on a double boiler and heat it slowly and carefully. If you warm it up too much, you could separate the oils in your mixture.

Preventing Runny Frosting

Follow the instructions closely. Frosting might seem simple, but making even a minor change to the ingredients can result in an unexpected change to the consistency. Make sure you’re using the right ingredients at the right measurements to make your frosting perfect. Unsweetened chocolate will make your frosting thicker than bittersweet or milk chocolate. Cocoa solids have starches in them, and unsweetened chocolate has a higher amount of cocoa solids in it while sweeter chocolates have more sugar and less starch. As a result, if a recipe calls for unsweetened chocolate and you use semi sweet, your frosting may turn out thinner than expected. Cream cheese and milk are other examples. Generally, there will not be much difference between frosting made with 2% milk and whole milk, but if a recipe calls for half-and-half or heavy cream, do not substitute milk in its place. Similarly, low-fat cream cheese has been known to produce thinner frostings when a recipe calls for standard cream cheese.

Mix in the liquid ingredients last. Typically, the fully liquid ingredients in frosting are added last. Following this procedure could help you to prevent runny frosting before it happens. If the sugar and butter (or shortening) are mixed first, add other liquids like water and milk afterward. In this instance, these ingredients are only added to make the frosting easier to whip and spread and should be added cautiously to prevent the frosting from becoming runny.

Add ingredients slowly and in small amounts. One of the biggest reasons why people often end up with consistency problems while making frosting is simply that a little too much of one ingredient gets added, throwing the entire recipe off. Both the liquids and powdered sugar need to be added slowly and in small amounts. If a frosting ends up being way too thick at first, the need to thin it by adding more liquid can result in the addition of too much liquid, which will make the frosting too thin. This is especially important when you’re adding ingredients to thicken up your frosting. Less is more!

Use caution with liquid flavoring like lemon juice. Some cream cheese frosting recipes call for a little bit of lemon juice as an added flavor ingredient. While it does give your frosting a nice zest, it also adds more liquid to your mixture, which can lead to runny frosting. If your recipe does call for lemon juice, consider adding lemon zest instead to avoid too many liquid ingredients. If you’d still like to add in lemon juice, mix it in at the very end. That way, you can see how the frosting looks before and after.