How to Measure the Acidity of Homemade Vinegar

by Andy Jackson

Items you will need

  • 150 ml plastic or glass beaker
  • 20 ml syringe
  • 10 ml syringe
  • 100 ml bottle of 0.2 N sodium hydroxide
  • 15 ml dropper bottle of phenolphthalein

Homemade vinegars may have different levels of acidity depending on the source of the vinegar (such as wine or apple cider), the length of fermentation and other factors. The acidity of the vinegar will determine its use. For example, milder vinegars may work well as salad dressings while more acidic vinegars are suitable for pickling. To determine the acidity of your homemade vinegar, you need to perform a process called titration. You can purchase equipment and supplies for your titration kit at stores that specialize in wine-making supplies.

Step 1

Use the 10 ml syringe to draw 2 ml of the homemade vinegar from the bottle. Add the vinegar to the plastic or glass beaker. Clean out the syringe to remove all traces of the vinegar and let it dry.

Step 2

Fill the 20 ml syringe with distilled water and add the water to the beaker.

Step 3

Add three drops of phenolphthalein to the vinegar and water in the beaker. Set the container aside.

Step 4

Fill the 10 ml syringe with the sodium hydroxide solution. Add the base to the beaker, one drop at a time, and gently swirl the beaker until the liquid turns pink.

Step 5

Calculate the amount of sodium hydroxide you used. Note the amount of base left in the syringe and subtract that from the capacity of the syringe. Example: with 3 ml left in the syringe, 10 ml – 3 ml = 7 ml.

Step 6

Multiply the amount of sodium hydroxide by .6 to determine the acidity of your vinegar. Example: 7 x 0.6 = 4.2 percent acidity.

Tips

  • Sodium hydroxide is caustic. Do not allow this substance to come in contact with your skin.

References (1)

  • “Homemade Vinegar: Make Your Own With Mother of Vinegar”; Patrick B. Watkins; January 1995

About the Author

Andy Jackson has been writing professionally since 2010. He is a certified personal trainer and yoga instructor in Cincinnati, Ohio. Jackson is also a lifestyle and weight management consultant whose work has appeared in various online publications. He holds a Bachelor of Science in kinesiology and health, and a Master of Science in sports studies from Miami University in Oxford, Ohio.