Start with a neutral alcohol source such as grain alcohol or diluted vodka
Dilute the alcohol to about 5% to 10% alcohol by volume
Add a vinegar mother or unpasteurized vinegar containing live acetic acid bacteria
Place the mixture in a clean, wide-mouth glass or food-safe container
Cover the container with breathable cloth to allow airflow while keeping out dust and insects
Keep the container in a warm, dark place around 25°C to 30°C
Stir gently once a day during the first few days if desired
Let the mixture ferment for several weeks until the alcohol turns into vinegar
Taste or test the acidity periodically until it reaches the desired sourness
Strain the vinegar if needed to remove sediment
Filter it for clarity if a cleaner appearance is desired
Pasteurize gently if you want to stop further fermentation
Bottle the finished vinegar in clean, sterilized containers
Store it in a cool, dark place
Use only food-safe materials throughout the process