Just wondering what you guys do to test your biodiesel after you make a batch. Going to pick up the system on sunday and want to make a batch to see how it works out.
First test I do is a preliminary soap test. Shake equal amounts water and biodiesel vigorously in a jar for 10 seconds. At room temp it should separate into two layers in about 20-30 minutes, clear water underneath, and absolutely no layer of anything whatsoever in between. I'll run another wash cycle if it does not meet this criteria. For futher testing I'll do a soap titration to see that I am achieving less than 50ppm soaps. The shake test is the first test however, and lately that's all I have been doing since my oil source and procedures have not varied at all in the past couple years, and perhaps I have become a bit complacent.
My first test for water content after I dry my biodiesel is to put a sample in the fridge until it reaches 45F. If it remains clear, I consider it dry. If there are any wisps or cloudiness I will do a hot pan test on it. Take a hot pan and swipe about a 1/4 teaspoon on it. If it bubbles and/or spatters, then you have moisture. If no reaction other than smoking, then it's dry. There is a further method I will employ called the weigh-heat-weigh method, which involves heating a sample in the microwave and weighing it before and after to see if any moisture evaporated out.
Please keep in mind that my preliminary soap and dryness testing methods are very rudimentary and just a starting point for testing your home brewed biodiesel.