Craters on Royal Icing: causes, prevention & fixes

I hate craters! That feeling I get when I see my dried Royal Icing with a depression of what earlier looked like the puffiest icing is no less than frustrating! After doing cookies for more than a decade I’ve learned some tips on how to drastically REDUCE the appearance of craters. I’ve invested hours upon hours of research, and tried many different tips and tricks along the years and haven’t found one specific thing that completely gets rid of craters, but I have found many tricks that almost eliminated them.

So, let’s answer the basic questions first, what are craters and where and why do they happen? Craters are unintentional holes or depressions that you can see in your royal icing after it dries, and 99.9% of the time they appear in smaller or narrow flooded areas. After a lot of research I’ve found different theories on why craters form. I believe that since it mostly happens in smaller areas, the culprit is moisture and air problems. When you flood with Royal Icing the edges dry faster and applying too much weight causing the icing to sink mostly in the middle. This issue is only made worse if this smaller / narrow section is a second layer and you let your bottom layer dry completely. 

Now that we got the boring theories out of the way let’s get to the interesting part, how to PREVENT craters in Royal Icing.

1. Try a thicker consistency. My flood icing is thin enough that when it dries it’s smooth but also creates volume. I like to use a 30-40 second icing consistency for flooding small/narrow sections.

2. After outlining and before flooding, add icing to the center of the section you are flooding, preferably a thicker consistency. The thick icing in the center will create a “support” for the flooded section, preventing these small areas from sinking.

3. Start flooding from the center

4. Run a scribe to the flooded area. This will break any air pockets hiding in the icing.

5. Don’t let your bottom layer dry completely. When a dry layer of icing is already present, it forms a barrier that disrupts the surface tension of the top layer causing it to crater. Add your top layer when the bottom has crusted but not dried completely.

6. Use a dehumidifier in your room. Royal icing has the tendency to absorb moisture from its surroundings. As Royal Icing is exposed to the humid air, it absorbs some of that moisture, which can affect its structure and texture. Also, in a humid surrounding air becomes trapped within the icing, this trapped air can cause small bubbles or craters to form on the surface as the icing dries and hardens.

7. Use a dehydrator. This has been the most successful tip / tool to reduce craters. The controlled drying process of a dehydrator paired with lower humidity levels reduces the risk of air bubbles or craters forming as the icing sets.

All the tips listed before have work for me using my Royal Icing Recipe.