Titration Test Instructions for Homemade Biodiesel

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 balance2 beakers or jarsa graduated dropperlitmus test strips or electronic pH meterlyeisopropyl alcoholdistilled 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.