Collecting Used Vegetable Oil for Homemade Diesel Fuel

German deepfried donut being cooked
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Making homemade diesel fuel is a simple enough process, but the first step is going to be finding the right supply of vegetable oil to get you started.

Talk it Up

Finding and maintaining a good supply of quality used cooking oil is as much about fostering relationships as it is about schlepping containers of the amber elixir. We’ve found the biggest ally is a friendly upbeat “we can scratch each other’s backs” demeanor: “Sure we can take that oil off your hands, and it won’t cost a thing.” When we first began making biodiesel many years ago, we were regarded as oddballs (maybe still are), and lots of the restaurant managers we approached didn’t believe we wanted the oil to make fuel for our cars (“you’re not going to cook with this are you?”) We’d laugh and assure them that yes, we really were going to make fuel out of it.

We’d even offer to drive over and let them sniff the sweet aroma of the exhaust. Some took us up on it, most didn’t.

Keep the Agreement

Nowadays lots of people know about biodiesel, so that hurdle is mostly cleared. But once you’ve successfully forged an agreement about the how, when and where you’ll pick up the oil, keep it. We can’t stress enough the importance of being prompt and reliable about pick-ups. This is especially so if the restaurant folks are good enough to put the oil in buckets or jugs for you. Do whatever you can to score that kind of an arrangement, because it is just shy of miserable when you have to pump it out of a sticky, gooey—often smelly—oil barrel out behind the building. Magnify that description by ten on a hot, humid July afternoon. You get the picture.

The Ride Home

When packing the vessels of oil in your vehicle, make sure the lids are on tight. If it’s in jugs, twist the lid nice and snug; if it’s in buckets, snap the lid evenly the whole way around.

Yes, it seems obvious, but it only takes one puddle of escaped oil sloshing around in your trunk to nail the point home. Yuck! Another helpful tidbit—strap or wedge the containers in position or place them in crates to stabilize them for the ride home. Otherwise, one corner taken just a tick too aggressively will net you the dreaded “overturned bucket syndrome.” Let’s just say that makes a loose lid pale by comparison.

A Final Word of Caution

Before you even talk about getting a restaurant’s waste oil, make sure it is vegetable oil. A lot of restaurants use liquid shortening, and although it will work, it’s much less reliable for good biodiesel reactions than pure vegetable oil. And while you’re at it, stay away from animal fat grease as well—it’s even more difficult to work with than shortening. It’s not good for your reputation among the restaurant folks if you agree to take their waste vegetable oil only to find it’s shortening or animal grease that you don’t want, and then have to extricate yourself from the deal. Worse still though? To just stop collecting it without a word to the manager. If you find, for any reason, that you need to discontinue collecting oil from a particular establishment, give them the courtesy of notification. If you leave them hanging, word travels fast, and you can even ruin the opportunity for other budding “biodieselists” who will follow in your footsteps.

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