Choose a neutral high-proof alcohol
Select bittering ingredients such as gentian root, quassia, cinchona, or wormwood
Add aromatic ingredients such as citrus peel, spices, herbs, or roots
Combine the ingredients in a clean glass jar
Cover completely with alcohol
Seal the jar tightly
Store in a cool, dark place
Shake the jar once daily
Steep for several days to several weeks
Strain out the solids through a fine mesh strainer or cheesecloth
Taste the liquid
Add water or more alcohol if needed to adjust strength
Add sweetener if desired
Bottle the finished bitters in a dropper bottle or small glass bottle
Label and store away from heat and light