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’m making a cake for my twin niece and nephew second birthday party in late July! The event center will be outside at a splash pad! I’m in Salt Lake City, Utah and the summers here can get up to 90°-100°. (Desert life sucks…) Will this buttercream survive extremely hot temps? I’m pretty sure the dessert table will be shaded.
Hi Shantell! Wow, that is very hot weather! As long as the dessert table is shaded and you keep the cake refrigerated until right before you head to the event, it should be totally fine for at least an hour or two. Hope that helps!
I doubled the recipe, including the meringue powder. Now the buttercream taste off. Sweeter than normal. Should I have only added 1 tbsp of meringue powder instead of 2? Do I just add a little more salt to balance the sweetness?
Hi Teresa-Ann! The doubling of the recipe should have produced the same flavor as long as all of the ingredients were doubled. If it’s sweeter than normal that would moreso point to adding too much powdered sugar. You could absolutely add more salt to balance the sweetness.
Hi there I am Rehvathi from Malaysia,I would like to know how to fix when the texture is grainy. Your help is much needed. Thank you.
Hi Rehvathi! If the texture is grainy, it typically means the powdered sugar isn’t fully dissolved. Keep mixing it on low speed for an additional 1-5 minutes. Hope that helps!
Greetings, I’m from India, where the weather is extremely hot and humid. I just wanted to ask if this butter cream would still work in humid conditions because I’m making an engagement cake for my niece, which is taking place in the midst of summer. Despite my concerns, I appreciate you sharing this recipe and can’t wait to try it.God bless you .
Hi Deepa! This recipe should work great in hot/humid weather but I would test it ahead of time just to make sure. Enjoy!
How long can this be unrefrigerated for?
Hi Stacey! It can technically be at room temperature for a few days, but if it’s on a cake in hot weather it will depend on how hot/humid and whether or not it’s in direct sunlight. It should last for several hours if it’s in the shade and the temperature is less than 85 degrees. The blog post above explains some experimenting I did with heat and humidity.
Hi I was wondering if I was to do the half butter half shortening with the mock Swiss meringue buttercream would it still be this stable?
Hi Kelly! I’ve never made mock swiss meringue buttercream (now I want to though!) so I’m not sure exactly what the results would be. It would be an experiment!
Hi, whitney nice to meet you! Living in Indonesia, which has high temperatures, has made me try lots of buttercream recipes that can withstand high temperatures. Thank you for this recipe ^-^ I have a question, if I want to use couverture chocolate, what’s the ratio between powdered sugar and couverture chocolate? Thankyou
Hi Lita! I’ve never tried adding melted chocolate to this recipe, so I’m not entirely sure. Instead, I would make this chocolate buttercream recipe with cocoa powder but sub half of the butter with high ratio shortening + add 1 Tbsp of meringue powder: https://sugarandsparrow.com/chocolate-buttercream-recipe/
The same brand of shortening you recommend is no longer available on Amazon. That brand does carry a buttercream mix that already has the meringue powder in it though. Have you tried that product, or is there a different brand of shortening you would recommend? The other brands I see on Amazon only have 50lb sizes available and are pricey. I’m a home baker, so I don’t need that much product.
Hi Laura! I have never tried that buttercream mix, my biggest concern is that it wouldn’t taste good. If that brand of high ratio shortening is sold out though there are other brands that will do just as well. Try Googling “high ratio shortening” or “cake and icing shortening” and any of the brands available should work. Some notable ones I’ve tried before are Sweetex and Alpine. Hope that helps!
I used this recipe for my cousin’s 3-tier, pearl covered wedding cake. It was an outdoor/ indoor venue in the beginning of September in Michigan (very hard to know how hot it could have been). This frosting held up beautifully and kept all the sugar pearls (many of them quite large) perfectly in place! Also, everyone LOVED how it tasted. Thank you much for an awesome recipe that took quite of a bit of anxiety out of putting together my first wedding cake for someone else!
Yay, Lillian! That makes me so happy, especially that it helped reduce your anxiety. Your first wedding cake is a HUGE deal and I’m so proud of you!
I’ve used this recipe 2x now for my Daughter’s June birthday in Wisconsin. Definitely holds up. Can’t find HRS but used Crisco and still works well.
Any suggestions on how I could get it to spread better?
Yay, Celina! So happy it worked well with Crisco! If it ends up too thick you can add an additional Tablespoon of room temperature milk to thin it out and make it more spreadable. Keep adding more room temperature milk as needed. Hope that helps!
Just wondering why you omit the meringue powder in the vegan version of this recipe? Thank you
Hi there! Simply because meringue powder is made from egg whites and isn’t vegan. Otherwise I would include it!
Thank you for this recipe! I was asked (by a friend of the family) to make my first wedding cake.
Being in SoCal during August made me nervous, but after a lot of research I went with this buttercream recipe. I made sure to test the buttercream on a practice cake. It was delicious!
I was told the wedding party loved the cake and it didn’t break a sweat! Thank you! I look forward to trying out your other recipes!
Yay, Teresa-Ann! I’m so glad this recipe helped and congratulations on making your first wedding cake! That is a huge deal and I’m so proud of you 🙂 So happy it was a hit with the guests too!
Hi! Love the attention to high-humidity requirements. Couple of questions:
Does this recipe scale well? I need to decorate over 40 cupcakes.
How many cups per dozen when piping decorations, not just smoothing some on?
Thanks!
Hi Kathy! Yes, this recipe scales really well. It makes 3 Cups, which is enough to pipe decorations on about 15 cupcakes. I’d make 2.5x the recipe to make enough for 40 cupcakes. Hope that helps!
Do you actually prepare the meringue powder, or do you just add the “dry” meringue powder to the ingredients?
Hi Sheri! I use this dry meringue powder: https://amzn.to/458wEEN hope that helps!
This is my new go to vanilla icing. I used it for my sisters wedding cake, outdoor reception-July in the South, it was hot and humid and this cake remained beautiful. Not only did it hold up well, it was absolutely delicious. It wasn’t nearly as sweet as my normal American buttercream and it didn’t have a strange aftertaste like when I use regular shortening. Thank you so much for sharing, it was a lifesaver!
I’m so happy to hear that, Shauna! Thanks so much for your feedback!