Gather the ingredients.

In a 1-pint (or larger) jar, add 1 cup 151-proof grain alcohol, 1 tablespoons quassia bark, 1 teaspoon cardamom seeds, 1 teaspoon coriander seeds, 1 teaspoon dried orange peel (minced), ½ teaspoon caraway seeds, and ½ teaspoon dried gentian root. Seal the jar, shake, and let the mixture stand in a cool, dark place for 14 days. Shake it vigorously once a day.

Strain the infused alcohol into a clean jar through cheesecloth to remove the botanicals. Gather the cloth into a ball and squeeze it to release as much liquid as possible.

Save the strained alcohol infusion for later. Label the bottle so you don't mistake it for something else.

Use a muddler or mortar and pestle to break up the strained botanicals as much as possible.

In a medium, nonreactive saucepan, add 2 cups water and botanicals.

Bring the water to a boil. Cover and lower the heat. Allow it to simmer for 5 to 7 minutes.

Pour this mixture, without straining, into a 1-pint (or larger) jar. Cover and allow it to sit for 5 days in a cool and dry place. Shake vigorously once a day.

Strain the infused water through cheesecloth and discard the botanicals.

Measure the infused alcohol and combine it with an equal amount of aromatic water in a 1-pint (or larger) jar.

In a small saucepan over medium-high heat, add ⅓ cup sugar . Stir constantly and allow the sugar to caramelize until it becomes liquid and dark brown, about 3 to 4 minutes.

Add the caramelized sugar to the alcohol and water mixture—the caramel will solidify, but it will dissolve within a few minutes.

Shake the bitters, then strain through cheesecloth to remove any sediment. Pour into a bitters bottle or small decanter with a tight-sealing lid.

The bitters can be stored for up to 12 months unrefrigerated in a cool place. Use in your favorite cocktail and enjoy.