In a large saucepan, melt the butter over medium high heat. Add the flour and cook for 4 minutes, stirring constantly. Add the garlic and continue to cook another 2 minutes. Whisk in the milk gradually, starting with about a quart. Add the lemon zest. Bring to a boil. Reduce to a simmer and cook for 10 minutes, stirring often. Stir in the lemon juice, salt, and pepper. Strain through a mesh strainer.
Yield: Enough to run through the largest home fountains. Multiply quantities by 4 for large commercial fountains.
Note: Select fountains hold 5-7 cups of fondue; Classic, Elite, and Signature fountains hold 7-9 cups.