Quinine Syrup

In a covered saucepan, bring all ingredients except the simple syrup to a boil and reduce heat immediately; simmer on low for a half hour, then remove from heat and allow to cool fully. Transfer to a carafe and chill for two days. Strain through a superfine chinois or cheesecloth, or by using a plunger press coffee maker. Return to carafe and refrigerate for a day or two, allowing sediment to accumulate on bottom. When layer seems stable, gently decant off the clearer liquid without disturbing the sediment “mud.” It should be about 3 cups at this point; add to this liquid an equal measure of rich simple syrup, mixing well. Funnel into a clean, cappable bottle and refrigerate. Makes roughly 6 cups or 1.5 liters.