Combine mint, water, vinegar, and sugar in a flat-bottomed kettle, stirring well; bring to a rolling boil, stirring constantly. Remove from heat, and strain through a sieve. Discard mint leaves.
Return strained liquid to kettle. Stir in food coloring, 1 drop at a time, until desired color is reached. Bring to a rolling boil. Add liquid pectin, and return to a rolling boil. Boil 1 minute, stirring constantly. Remove from heat, and skim off foam with a metal spoon.
Quickly ladle jelly into hot sterilized jars, leaving 1/4-inch headspace. Cover with metal lids, and screw bands tight. Process jelly in boiling-water bath 5 minutes. Serve with lamb or other meats.
Note: Let Mint Jelly stand at least one week to allow flavor to intensify.