Step 1: Add the food coloring to the glass
You can pour the beer first and then add the food coloring, but it gets stuck in the foam and you have to stir it in and it never really looks nice. Now, when I was first testing different amounts of different colors, I had to add the food coloring after the initial pour, but I recommend doing it the other way. You’ll have to read the rest of the article and look at the pictures to decide which color food coloring, and how many drops, you want to use. I went with three green drops of food coloring.
Step 2: Pour the beer
Pour the beer into your glass, over the drop(s) of food coloring, and it will mostly stir up on its own as you pour. If it needs a little more stirring, you can use a bar stir stick, which will agitate the foam so you don’t lose the head. (Stirring with a spoon tends to make the foam disappear, but in a pinch a knife, chopsticks, straw or anything that’s straight should work.)
And that’s it. And now for the pictures that will show you the different experiments I did to find the color I liked best. I started with two glasses of Harp Lager, which is a light amber color. Results may vary depending on the beer you use, so I included this photo for you to compare with your beer.
These are the beers with one drop of green (left) and one drop of blue (right). They look a lot alike at this point, and it’s more olive than the emerald green you want for a St. Patrick’s Day beer.