A quick word on different kinds of grease. They are not all alike. Or rather, by the time you get them, they have not all be “used” the same. So far, in my 5,000 miles of WVO (waste vegetable oil) experience, here’s what I’ve deduced:
Asian Food Restaurants–seem to have the cleanest grease. It’s usually still sort of pale golden and doesn’t have a lot of shit floating in it. If you can get your WVO from a Chinese joint, I highly recommend it as there will be less filtering/settling time involved in your whole process. And yes…your car will smell like the back alley of a Chinese restaurant.
Burger n’ Fry Restaurants–I get a good deal of my grease from the wonderful folks at O’Donahue’s Pub in Nyack, NY. They are extremely diligent about changing out their fryer grease and keep it extremely clean. However, with any grease that has been used to cook potatoes, you need to be prepared to wait a few extra days for the H2O to settle out. Remember, water is heavier than oil, so it will eventually drop down to the bottom of your barrel. That being said, I’ve never waited more than a week after filtering before I pump the crap into my car. I know you’ve read that you should filter down to .000002 microns and wait three months for settling. Bollocks! 5 microns and two days is my average. Who’s got time for all that work and waiting. I haven’t had any issues yet. Maybe I’ll eat my words in the next post.
Chicken, fish or anything with a lot of batter–This stuff is liquid death. I’ve recently obtained access to a huge supply of grease from a busy Italian restaurant that makes the best fried calamari around. All that flour is good on the calamari but bad for your grease. I usually can’t get more than 10 gallons filtered before I have to clean out my 5 micron sock filter. And the stuff that it leaves behind is evil. Sort of the consistency of thick apple butter. Very nasty stuff. Also, you will most certainly leave a trail of fish-smoke wherever you drive.
So in summary:
French Fry- good, but let the water settle a few days
Fish and Chicken (floured or battered)–God help you