Wearing nitrile gloves, slice the stems off of the jalapeños. Core out the seeds with a small spoon. Slice each pepper into 1/8 to 1/4-inch slices.
Stir the remaining ingredients (vinegar, sugar, garlic) together in a large sauce pot. Heat over medium high heat stirring occasionally for about 10 minutes or until it comes to a frothy boil. Reduce heat, and simmer for 2 minutes.
Stir in the jalapeños, and simmer for 8 more minutes, stirring occasionally. They will start to change to a darker color.
Remove the peppers from the syrup using a slotted spoon. Spoon into two half pint glass jars.
Bring the syrup to a boil and boil 5 more minutes. Carefully pour the syrup into the jars of peppers. Allow to cool at room temperature for at least an hour, and then refrigerate.