This Summer, something happened to me that has never happened before (to my knowledge at least): one of my cakes melted in the outdoor heat. I made a birthday cake for a dear friend’s daughter – my vegan vanilla cake with vegan vanilla buttercream. The party was outdoors and the temperature was around 85 degrees. I refrigerated the cake up until I needed to drive it to the party, thinking that would be enough to preserve it for a few hours. But about an hour after the cake was displayed, the thing started melting (along with my heart). Thankfully, these were the kind of friends who were able to laugh about it with me as it all fell apart. Here’s a before and after:
Although it was a first for me, it got me thinking about so many of you who live in hot and humid climates. I’ve even gotten questions over the years from said people wondering how to make their buttercream more heat stable. The fact of the matter is, the butter in buttercream frosting starts to break down when it’s in an environment that’s above 82 degrees, and vegan butter has an even lower melting point. So, I thought I’d do some experimenting on how to add stability to your buttercream (both vegan and non) for those hot and humid days while keeping your frosting nice and tasty.
For my experiment, I created four mini cakes and frosted them each with different frostings using my favorite vanilla buttercream recipe as a base:
- All butter (aka the recipe as-is)
- Half butter and half shortening
- Half butter and half shortening + meringue powder for added stability
- Half vegan butter and half shortening (with coconut milk as the liquid)
I refrigerated each cake until firm before placing them in the direct sun on an 88 degree day with 35% humidity and here’s a video of what happened:
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Buttercream Heat Test Results
Over the course of the two hours I had the cakes in the sun, none of them completely melted, which was kind of disappointing because I wanted things to be more dramatic. The day just wasn’t hot enough. So in the end, I had to break out the hair dryer to see what would happen with more heat applied.
After I cranked up the heat on these cakes, the all-butter buttercream frosted cake melted into soup:
The cake with the half vegan butter and half shortening got a huge air bubble in the frosting that started to melt:
The half butter and half shortening frosted cake looked pretty good after one hour but this is after two hours out in the direct sun + hair dryer:
And the half butter/half shortening with added meringue powder had relatively no change:
I did try an all-shortening frosting because I hear that’s really heat stable, but just couldn’t get over how terrible it tasted. You’d have to use a lot of flavoring to get it to taste normal (and even then, the texture is a little weird).
I concluded that when you’re up against crazy heat (according to these test results at least), use half butter and half shortening with meringue powder. If you’re in need of vegan frosting, you can chance it with half vegan butter and half shortening or try the all-shortening route (with the meringue powder omitted) if you can get it to taste good. I’m going to add my preferred recipe below and in the notes, I will show you how to adapt the recipe for using all-shortening, making it vegan, etc.
What is High Ratio Shortening?
When you think of shortening, what do you think of? Crisco is what I thought of before all my research into heat stable buttercream. It turns out that Crisco (and most shortening) is made with zero trans fat – in other words, it won’t add enough stability to your frosting. So in order to add that stability, you need what’s called high ratio shortening (sometimes called icing shortening). High ratio shortening has a high ratio of fat with added emulsifiers and no added salt or water. In other words, the micro emulsifiers in it help your frosting to hold more sugar and liquid and thus make it more temperature resistant.
Unlike Crisco though, high ratio shortening can’t be found at your typical grocery store. I found this high ratio shortening on Amazon,, but there are other brands that cake decorators use (see the list below). You might be lucky and live close to a cake decorating shop that sells high ratio shortening, so check your local area to see. If you can’t find it locally, here are some links to online cake shops I’ve collected (not sponsored):
- Sweetex High Ratio Shortening
- Alpine High Ratio Shortening
- Bake Supply High Ratio Shortening
- Oasis High Ratio Shortening
What is Meringue Powder?
Meringue powder is basically powdered egg whites, but it also contains cornstarch, sugar for sweetness, gum arabic for thickening, and cream of tartar which helps with stabilizing. If you want to try just adding meringue powder to your buttercream without adding any shortening, add 1 Tbsp (per batch of frosting) by mixing it into the powdered sugar before adding it to the butter in the linked recipe.
With taste and stability in mind, here’s my new go-to recipe for heat stable buttercream:
Heat Stable Vanilla Buttercream
Ingredients
- 1/2 Cup (113g) unsalted butter, room temperature
- 1/2 Cup (100g) high ratio shortening*
- 3 1/2 Cups (420g) powdered sugar
- 1 Tbsp meringue powder
- 2 tsp vanilla extract
- 2 Tbsp whole milk or heavy whipping cream, room temperature
- 1/4 tsp salt, or to taste
Instructions
- With a hand mixer or paddle attachment on your stand mixer, cream the butter and shortening on medium-high until it’s creamy and light (almost white) in color. About 7 minutes.
- Whisk the meringue powder into the powdered sugar. Then, with the mixer on low, add the meringue/powdered sugar mixture one cup at a time, scraping down after each addition and making sure each cup is fully incorporated before adding the next one.
- Add vanilla, milk, and salt and mix on low for another minute until fully incorporated.
Notes
- Frost 12-15 cupcakes with a piping bag
- Fill and crumb coat a three-layer 6-inch cake or two-layer 8-inch cake. To have enough for frosting and decorating as well, double the recipe.
Did you try this recipe? I want to know that you think! Let me know in the comments below or feel free to tag @sugarandsparrowco on Instagram and show me. I love to see what you create! And if you have a go-to recipe for heat stable buttercream or technique that you swear by, let us all know in the comments. We’re all in this together!
Hi,
I live in the UK and we are currently experiencing a heatwave temp up to 30 Celsius and I have to bake a decorated a cake for this weekend.
My question is can I use Crisco or trex as I can’t get hold of the other shortenings you mentioned? Which one would be better? The temperature for Saturday when I’m decorating in 26 Celsius and Sunday when it’s going to be out is going to be 22 Celsius. Also I have seen a post somewhere saying you can substitute half the icing sugar with royal icing sugar and get the same affect as using shortening but without the taste, do you know if this is true?
Hi Sharon! I would recommend Crisco over Trex for the frosting, it will keep the shape of the frosting best! I’ve never heard of royal icing sugar but I know that adding meringue powder (which is an ingredient in royal icing) will add stability. 22ºC-26ºC isn’t horribly hot, so I think you’ll be fine with using half butter and half Crisco for the frosting, then store the cake in the refrigerator until 1-2 hours before serving. Hope that helps!
Hello!! Your recipe looks amazing and I love that you use meringue powder in it. I am wondering if this stable buttercream frosting meets the requirements for Wisconsin cottage law? I am looking for a stable buttercream for my cookies and am hoping this would work!
Hi Kendra! I’m not familiar with Wisconsin cottage law, so I can’t say for sure. I would look up what the law requirements are and compare it with the recipe. The buttercream doesn’t require refrigeration because the small amount of dairy is preserved with the sugar content, and it stays fresh for about 5 days at room temperature. I hope that helps!
Hello. Is it OK to store my cake outside of the refrigerator overnight, if I use the recipe that is half butter, half shortening, and meringue powder, and the room temperature is below 74°?
Hi Heather! Yes, it’s totally fine to leave the cake out overnight for a day or two. I like to refrigerate my cakes just to preserve the decorations but I always bring them back to room temp for serving. Hope that helps!
Hi Whitney, I have a few questions that I need answered quickly I have to start baking in two days and I want time to practice!! Sorry for rushing you. So I’m baking 108 cupcakes for a 4 hour long birthday party it will be inside but with that many people in a small room it will be hot. Also I will be decorating my hem two days in advance and serving them on the third day. So my first question is will vegetable shortening without it be high ratio be good enough for it to sit at room temperature for three days? And will the vegetable shortening change the consistency of the frosting to much to where it would not be able to be piped? Basically will it all work out completely fine if I use it. Second I know I will have to try to cool the cupcakes down but they will be sitting in a building completely without AC and without a fridge or a freezer. Will they be okay? I think that’s all I need to know I’m sorry it’s a lot, but I do need to know really quickly the answers.
Hi Delaney! Using vegetable shortening will make the frosting more stable, even if it’s not high-ratio shortening. It will still be perfectly pipeable. I would substitute half of the butter in the recipe with shortening for an event with those conditions. You could consider substituting all of the butter with shortening, but the flavor of the frosting won’t be as rich as it is with some butter in the mix. I hope that helps!
Hi there I made the heat stable vanilla buttercream and it was to die for everyone loved it!! Just wondering if I were to make a lemon flavoured batch of this and added lemon juice instead of the vanilla if that would affect the stability in any way ☺️
Hi Tayana! I’m so happy you love this recipe! For lemon flavored buttercream I would use this recipe: https://sugarandsparrow.com/lemon-buttercream-recipe, but sub half of the butter for shortening and add 1 Tbsp meringue powder. Enjoy!
Hi! Thank you so much for this recipe, I want to try it out, but meringue powder is quite hard to get here in my area, what’s a nice substitute for this?
Hi Joh! I have heard that an equal amount of cream of tartar can be used as a substitute. If you can’t find either of those, you can omit that part of the recipe and still have a great heat stable frosting with the shortening/butter combo. Hope that helps!
Thank a lot for sharing this recipe turned out great, was for a wedding cupcakes and it was extremely warm with no AC.
Yay, Rina! I’m so happy to hear that it was a success!!
How would this work with cream cheese frosting?
Hi Porsche! In the same way, you’ll just sub half or all of the butter in a cream cheese buttercream recipe with high ratio shortening, and add 1 Tbsp of meringue powder per batch.
How would you do the recipe with cream cheese or do you have a stable cream cheese frosting recipe that would work without it being melted?
Hi Rochelle! For a more stable cream cheese frosting, I would sub half of the butter in the recipe with shortening and add 1 tbsp of meringue powder to this recipe: https://sugarandsparrow.com/cream-cheese-buttercream-recipe/
Hello I was wondering if I can substitute the milk or heavy cream for water just because I cannot use/sell anything with potentially hazardous ingredients as a local cottage food producer. Thank you:)
Hi Skylar! Water won’t bring this buttercream recipe together nearly as well since it doesn’t have any fat to bind the ingredients together. I think the dairy ingredients in frosting are okay as long as it’s not cream cheese buttercream, which requires strict refrigeration. This frosting doesn’t require refrigeration since the high amount of sugar in the recipe ends up preserving the dairy. If you’re worried about it, you could use a non-dairy milky. Soy milk would be my top recommendation.
Hi, the amount of powdered sugar is too sweet for my taste. Can I reduce one cup of sugar and add an additional spoon of merengue ?
Hi Claudia. You can try reducing the amount of powdered sugar, although I’m not sure if the consistency will be too thin when reducing it by a full cup. I have reduced the amount by 1/2 Cup successfully, but a full cup will be an experiment. Let me know how it turns out if you try it!
What kind of shortening do you recommend? Does it make it taste different if you only use shortening? Do you have any recommendations for making an orange buttercream?
If you can find hi-ratio shortening (aka icing shortening) that is the best to use because it contains certain ingredients that allow the frosting to hold more sugar and liquid and thus make it more temperature resistant. This is a good brand: https://store.sweetlifecakesupply.com/products/sweetex-high-ratio-shortening?variant=43727730180399 but any vegetable shortening will be more heat resistant than butter. It will taste different if you use all shortening, I explain the flavor in the blog post above.
By orange buttercream do you mean flavor or color? For my favorite orange flavored buttercream recipe I recommend the frosting from this cake: https://sugarandsparrow.com/cranberry-orange-cake-recipe/ if you mean coloring the frosting orange, I’d recommend adding some orange food color gel until the desired color is reached.
Hi, how do you prevent your cakes from sweating after removing it from the fridge when it it for a daytime outdoor event? I’ve found that the cake is fine until I put it in the fridge, as it sweats once removed. I’ve tried letting it sit in a cake box for about an hour but it still sweats once it’s removed from the box and put on display. Thanks
Hi Natalie! I’ve never had an issue with condensation, but probably because I live in a really mild climate (pacific northwest). From what I’ve read, the only thing you can really do is minimize the temperature difference between the refrigerator and the outside air. Condensation happens when there’s a big and/or sudden change in temperature. I have found that when I keep my refrigerator at around 40ºF I never have an issue with condensation (my house is about 70ºF), but when I keep the refrigerator at a lower temp like 34ºF the cake is more likely to have condensation. Perhaps try experimenting with your refrigerator temperature? That’s the only advice I can offer!
Just moved to Louisiana and it’s the first time I’ve had to think about heat stable frosting for a September party. Learned a lot from this, and it worked wonderfully!
Yay, Rae! So happy this was helpful!
Just made this recipe and it was a huge hit and the frosting stood up to the heat. I read in your article it can be refrigerated up to two weeks. How long could this frosting be left on the counter and can leftovers be put in freezer for later use?
Hi Amanda! So happy this frosting was a hit! It can be left out at room temp for up to 2 days, leftovers can be kept in the freezer for up to 2 months. Hope that helps!
I made a triple batch of this (which all fit in my kitchen aid stand mixer bowl, yay) and it was just enough to crumb coat, frost, and pipe decorations on two 9×13 cakes. I had about a cup of frosting leftover. It pipes and holds its shape super well. I bought the high-ratio shortening from Sweet Life Cake Supply and was happy with it.
Yay, Abby! So happy this recipe was a hit!
I tried the recipe, and I’m not sure what I did….or didn’t do. My icing became almost like playdough. I did use heat to increase the food coloring effect. Once cooked and whipped the color was great and it looked smooth, but was not easily spreading and felt very much like playdough. I used heat again and hot water for my bench scrapper to smooth it out. It was not my easiest moment. But it does appear to hold up well. I live in Texas and this cake will be at a Pier by the lake, and will definitely need the stability. I’d like to hear your take on what may have gone wrong please.
Hi Krystal! It definitely shouldn’t have a playdoh-like consistency. It should just be a spreadable, pipeable frosting consistency. I’ve never tried the heating method while coloring this particular recipe, so my first thought is it could have something to do with that (maybe a chemical reaction with the meringue powder in the microwave?). Was the frosting a good consistency until you heated it in the microwave for coloring? My only other thought is that somehow you added too much powdered sugar/not enough liquid. Hard to say for sure.
Hello!
The shortening you recommend isn’t available any longer and the Sweetex is a 50 lb container LOL. What other brands do you recommend? I’d like to try this substitute for the generic, everyday vegetable shortening. No cake or kitchen stores anywhere near where I am, unfortunately!
Thank you – and please keep your great recipes up!!
– Fiona
Hi Fiona! High ratio shortening is hard to come by lately! It should still work with regular vegetable shortening as a sub.