Step One: Add Water or Corn Syrup
While making your royal icing, you can add a few drops of water or corn syrup to help keep it soft. Start with just a couple drops of water, mix it in with the icing and add more if needed to reach your desired texture.
Corn syrup will also help the icing from getting a stiff consistency. Up to two tablespoons of corn syrup can be added to one pound of royal icing.
Step Two: Keep the Royal Icing Soft While Using
While you are using your royal icing in a piping bag, keep it soft by placing it in a bowl or glass with a damp paper towel at the bottom.
The moisture from the damp towel will keep the royal icing from hardening up and prevent the tip from clogging up. This a great hack for when you are using multiple colors of royal icing to decorate and have multiple piping bags you are using.
Step Three: Store Your Leftover Royal Icing
Once you are done decorating, you want to make sure to properly store your royal icing. This will prevent it from getting hard and crusty.
To help prevent royal icing from drying out or hardening, it is important to keep it sealed. When storing royal icing, keep it in an airtight container, with a cover of plastic wrap on the surface. This will keep the royal icing soft and keep it from hardening up.
If you have your royal icing in a piping bag, you can tie off the end with a rubber band. This will help keep it soft without having to take it out of the piping bag.
You can also use a slightly damp paper towel on top of the royal icing when you are storing it in an airtight container. This will keep the icing from crusting over.
When making your royal icing, it is important to not overmix it, as it may create a stiff texture.