How to Make Invisible Ink for Writing Top-Secret Messages

Make invisible ink to send secret messages just like a spy, using nothing more than everyday kitchen ingredients!

With a simple combination of grape juice and baking soda, you can create your very own disappearing ink, perfect for crafting top-secret notes that can’t be seen by the naked eye. This fun and easy recipe allows you to write hidden messages that only reveal themselves when exposed to the right conditions.

WHAT YOU’LL NEED

• 1 tablespoon of baking soda
• ¼ cup of water
• Grape juice concentrate
• Paintbrush or cotton swab
• Paper
• Two small bowls

HOW TO WRITE A SECRET MESSAGE WITH INVISIBLE INK

1. Mix the baking soda and water in a small bowl. This is your invisible ink.

2. Dip a finger, cotton swab or paintbrush into the “ink.”

3. Write your message on a piece of light-colored paper. You may want to write it in code using this build-it-yourself secret-code wheel.

4. Let it dry completely.

HOW TO REVEAL AND READ AN INVISIBLE INK MESSAGE

1. Lightly paint grape juice concentrate across the paper with a brush.

2. Your message will slowly appear as the juice saturates the paper.

WHY IT WORKS

Baking soda and water make an excellent invisible ink because when the solution is applied to paper, it dries clear and remains undetectable.

The magic happens when you brush the paper with grape juice. The acidity in the grape juice reacts with the alkaline baking soda, causing a chemical reaction that changes the color of the writing. This reaction reveals the hidden message, making the writing visible. It’s a simple yet effective method for creating secret messages using common household ingredients.

If you’re interested in secret messages and codes, check out the Cub Scout Code of the Wolf elective adventure or the Signs, Signals and Codes merit badge.