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:
If you’re into cake videos like this one, head on over to my YouTube Channel. You’ll find all sorts of cake decorating tutorials, recipes, and my entire Cake Basics series in video format. I’m always adding new videos there, so be sure to hit the subscribe button so you’ll always be the first to know about a new one.
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. That means the 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, which claims to be made specifically for cake making, but there are other brands (Sweetex is one I hear about a lot) that cake decorators use. You might be lucky and live close to a cake decorating shop that sells high ratio shortening, so check your local area to see.
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
A tasty vanilla buttercream that stands up better to hot and humid environments. Makes enough to fill and frost a double layer cake, fill and crumb coat a triple layer cake, and frost about 20 cupcakes.
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.
Recipe Notes
Make Ahead Tips: This buttercream can be made ahead and stored in an airtight container in the refrigerator for up to two weeks. When you’re ready to use it, bring it back to room temperature and re-whip in your stand mixer to bring back to smooth buttercream consistency.
To Make It with Vegan Butter: substitute an equal amount of vegan butter (I love Earth Balance Sticks) for the unsalted butter, omit the meringue powder, add 1 Tbsp vanilla instead of 2 tsp, add 1 Tbsp dairy-free milk instead of 2 Tbsp whole milk (my favorite is unsweetened coconut milk), and salt to taste.
To Make It All-Shortening: omit the butter and use 1 Cup of high ratio shortening, 1 Tbsp of vanilla (and ¼-½ tsp of any other flavorings you’d like, such as butter extract, almond extract, etc), 4 Tbsp of whole milk or non-dairy milk, and keep the salt amount the same.
To Make It Extra White: After all ingredients have been incorporated, add 1-2 tsp of Americolor Bright White or icing whitener of your choice.
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!
Thank you for posting this! I live in Miami and can’t wait to try it!
Of course! I hope this helps!
Do you refrigerate your cakes after you decorate if delivering the next day or leave them out?
Hi Maddie! I always refrigerate fully decorated cakes before delivery. It’s much easier to preserve the details and transport that way. Here’s a blog post that shows my process: https://sugarandsparrow.com/making-cakes-ahead/
Hi, I live in Brisbane and have a couple of questions.
If I use your white chocolate frosting recipe to cover a mud cake
How heat resistant is it?
Can I put the iced cakes into the fridge overnight and have no effect on the frosting when it sits out?
Hope you can help
Kate
Hi Kate! Since I didn’t run the experiment with my white chocolate buttercream recipe I can’t say for sure how heat stable it is. I have heard that the addition of white chocolate in that recipe does make it more heat stable. I would try adding 1 Tbsp of meringue powder in with the powdered sugar for every batch of the white chocolate buttercream you’re making and definitely refrigerate the cake until you’re ready to deliver it. Hope that helps!
I live in Barbados and it’s extremely hot here sometimes and everytime I try to frost cakes, it’s melts aways. I’m looking forward to trying your recipe.
Can I use 2% milk instead of whole milk?
Hi Shae! I’m excited for you to try this recipe! 2% milk should be fine with this recipe.
Hi! What ingredient can I substitute for high ratio shortening, I cant find in my country. Thank you!!
Hi Nicole! If you can’t find high ratio shortening, I would either just use all butter and add meringue powder to help stabilize it, or ask around other cake makers in your area to see what they use to combat the heat. Hope that helps!
This is THE BEST buttercream recipe I have ever used in the 31 years I’ve been cake decorating!
I live in the UK so heat and humidity isn’t generally a problem, however central heating and warm houses can be.
I used ‘Crisp n Dry’ shortening in replacement for the shortening in this recipe, however I used 50g instead of 100g and added the other 50g to my unsalted butter. I also added 3tbs of double cream instead of 2 as I found it was slightly too thick for covering the cake!
It’s perfect and tastes amazing, not sickly at all, I was worried I would be able to taste the shortening but I can’t at all!
I haven’t finished decorating my cake yet so obviously it hasn’t been through the stability test yet, but the buttercream has been out of the fridge for the last 4 hours (covered with cling film) and the consistency hasn’t altered in the slightest like others have done in the same conditions!!
I guarantee you will not be disappointed with this recipe at all and thank you for sharing, I will never use anything but this from now on
Yay, Wendy! That makes me so so happy! Thank you for taking the time to let me know and I’m so thrilled you’ve found a new go-to buttercream recipe for the warmer months.
An update on the finished cake!
Perfect! It was taken to a restaurant and was kept in the kitchen there until the end of the meal! The buttercream did not even break a sweat
Once again thank you
Yay, Wendy! What a relief!
[…] “Stable Vanilla Buttercream Recipe for Hot Weather” by Sugar and Sparrow. Okay, I’m sharing this one a little late, but maybe it’s still hot where you’re from? In any case, check out this blog post because it’s really cool—Whitney “heat tested” a bunch of different buttercreams under the warm, hot sun and eventually developed a recipe that was heat stable. Amazing! […]
I tried this heat resistant butterceam recipe for a birthday cake because it was 90 degrees in San Diego that day and the cake lasted the entire party!
I ended up making 3 batches of it for a 2 tier cake with 3 x 8” cakes and 2 x 6” cakes.
My only question is: Can we double this recipe?
Totally recommend this recipe!
Thanks for this recipe
YAY, Jessica! It makes me so happy to hear that this recipe worked well for your outdoor party and the cake lasted! You can absolutely double (or triple!) the recipe. Thanks for taking the time to let me know what a hit it was!
I love this recipe! I’m wondering if you’ve tried a cream cheese version of this icing?. I’m making a pumpkin cake fir an outdoor party and was hoping to have cream cheese icing that will hold up to 88 degree weather.
Thanks so much, Julie! I’m so happy to hear you loved this recipe! I haven’t tried this with cream cheese buttercream before but if I were to attempt it, I would just replace half of the butter in the buttercream recipe with high ratio shortening and add 1 Tbsp of meringue powder. Hope that helps!