Coral Aquarium Cake Tutorial by CakeBoss

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How to make a coral for an ocean cake or aquarium cake

Skill Level: Beginner

Final aquarium cake

This tutorial demonstrates how to make realistic coral for cake decorations out of grape stems and royal icing. This is a great technique because not only is it very easy, but it doesn't require you to buy specialty ingredients or mess around with boiling sugar or isomalt. Grape stems are ideal because they are inexpensive, non-toxic, and they provide a frame that mimics the organic, random shapes of coral.

Supplies:
Grape stems
Royal icing
Piping bags with round tips.
Gel colors (optional)
Luster or pearl dust (optional).

Step 1: Eat some grapes

You'll want to acquire some grape stems of various sizes. This technique is slightly more effective if you let them dry for a day or two so they don't bend while you're working with them, but it's not necessary.
Dried grape stems
Grape stems that have been dried for 1-2 days.

Step 2: Making royal icing

Start by making royal icing. Royal icing is simply powdered sugar, meringue powder, and water. It increases in volume as it's whipped. When it dries, it becomes almost rock-hard, and because of this, it is useful in hundreds of ways in the sugar arts. As with most things, it's best made in a stand mixer.

Royal icing just beginning to be whipped
Royal icing as it looks when you start whipping.

Royal icing after 8 minutes
Royal icing after 8 minutes in the mixer.

Stiff royal icing ready for use
Stiff royal icing ready for use.

Step 3: Applying icing to the grape stems
Today I'm making orange, yellow, and white coral, but the color possibilities are endless! Coral exists in all kinds of brilliant colors - yellow, orange, blue, purple, fuchsia, white. The sky's the limit as far as your color selection.
icing colors, stems, and tips

Round tips anywhere from size 5-8 are good for this job.
beginning to cover stem

beginning to cover stem

Begin using your piping bag to apply icing to the stem. We're not going for full coverage, just cover as much as you can before it gets goopy and hard to hold.
partially covered stem
When you've covered as much as you can, stop piping and let the stems dry for several hours or overnight. You want the icing to become hard enough so that you can pick it up without it smudging.
 
partially covered stems

partially covered stems


You can cover the tips of your piping bags with wet paper towels to keep them from getting hard and crusty while you wait. *A note about letting royal icing sit: after a few hours it starts to take on an almost marshmallowy consistency, with air bubbles throughout. Under normal circumstances, you would always re-whip royal icing before you use it. But for coral, the air bubbles actually enhance the look, so I just leave it in the bag and use it as-is.

wet paper towles over tips

Step 4: Final coverage of royal icing
After the first layer of royal icing has dried hard enough so that you can pick up the stems without smudging or breaking it, you're going to go back over the stem with your piping tip, piping over all the spots that you missed the first time. There is no science to the placement of the icing! Coral is organic, weird, bumpy, and random - so your grape stem coral can be, too!

second coating of royal icing

completely covered stems

Step 5 (optional): Luster or pearl dust
I happen to be of the opinion that there isn't much that can't be made better with a little pearl or luster dust, so after the second coat of royal icing dries, I dust my coral with matching dust - in this case, Gold Pearl for the white and orange, and basic yellow luster dust for the yellow corals. (The brush is a cosmetics brush that I use exclusively for decorating.

brushing dust onto coral

brushing dust onto coral

That's it! This coral is destined for this cute and whimsical ocean cake.
aquarium cake

Let's get a close-up of that coral.
coral close-up

coral close-up

large coral close-up

This easy cake is covered in fondant. The fishes on top are styrafoaom balls (from the craft store) covered in fondant. All the fishes on the sides of the cake are fondant. The seaweed is royal icing, the shells are fondant pressed into candy molds, then dusted with luster dust, and the sand is brown sugar.


large coral close-up