Science Energy Titration Test for Homemade Biodiesel Test waste vegetable oil with titration By Christine & Scott Gable Writers Millersville University Christine and Scott Gable are hybrid auto and alternative fuel experts who have brewed their own biodiesel and traveled 125,000 miles on waste vegetable oil. our editorial process Christine & Scott Gable Updated October 25, 2019 WLADIMIR BULGAR/Getty Images Share Twitter Pinterest Email Science Renewable Energy Fossil Fuels One hundred percent virgin or lightly used waste vegetable oil (WVO) requires 3.5 grams of lye per liter of oil to cause a biodiesel reaction. Heavily used oil can require significantly more and must be tested to evaluate its acidity. Titration is a common method used to determine the appropriate amount of lye (base) needed for a particular batch of WVO. How to Perform a Titration Test Equipment Needed an electronic scale or beam balance 2 beakers or jars a graduated dropper litmus test strips or electronic pH meter lye isopropyl alcohol distilled water Steps to Complete a Titration Test Measure 1 gram of lye on a scale. Measure 1 liter of distilled water into a beaker. Thoroughly mix the gram of lye with the liter of water until it’s dissolved. Measure 10 milliliters of isopropyl alcohol into a separate beaker. Thoroughly mix 1 milliliter of used vegetable oil into the alcohol. With a graduated eyedropper, put a 1-milliliter drop of the lye/water mix into the oil/alcohol mix. Immediately check the pH level of the oil/alcohol mix with a piece of litmus paper or an electronic pH meter. Repeat step 7, keeping track of the number of drops used, until the oil/alcohol mix has reached a pH level of between 8 and 9--normally no more than 4 drops. Calculate the amount of lye needed for the biodiesel reaction by adding 3.5 (amount of lye used for virgin oil) to the number of drops from step 7. For example: suppose a titration uses 3 drops of lye/water. Adding 3.0 plus 3.5 = 6.5. This hypothetical batch of oil requires 6.5 grams of lye per liter of oil.