You can buy cinchona, whole gentian root, and soft-stick cinnamon in bulk from herbal medicine retailers and other specialty herb shops. And please use a scale for measurement; it makes a difference. I've kept the quantities in metric weights because it's important to be precise. Any electronic scale will have a setting for metrics as well as U.S. weights. —Jeffrey Morgenthaler
powdered cinchona bark (red will be more assertive, yellow is milder and less bitter)
whole gentian root
Ceylon soft-stick cinnamon, broken by hand into small pieces
lemon peel, peeled with a vegetable peeler
grapefruit peel, peeled with a vegetable peeler
To make the tincture: Dissolve the powdered cinchona bark in the vodka. Mix well, and then strain through a paper coffee filter fitted into a strainer (or a filter cone, if you have one) and suspend over a large enough container to accommodate the final volume of vodka. This process could take up to 1 hour, so don't worry if it seems like nothing is happening. (The tincture lasts forever.)
To make the aromatics: Combine all the ingredients for the aromatics in a medium saucepan. Heat over medium heat just until boiling, reduce the heat to low, and simmer, covered, for 20 minutes. Strain out the solids and let the liquid cool.
Stir 1 1/2 ounces (45 milliliters) of the quinine tincture into the cooled aromatics, and then bottle. Seal tightly and store in the refrigerator for up to 2 weeks.