I’ve gotten a lot of questions regarding the weight and cost for vegetable oil, (particularly bulk vegetable oil), corn oil, and the like, so I’ve decided to put a little more effort into the research and firm up the numbers. In order to get the widest range of subject matter, I took a trip to my local Wal-Mart to take some measurements.
This post details the price and weight by volume of bulk vegetable and corn oil (our primary subject matter) as well as the price and weight by volume of motor oil and gasoline.
Since I’m taking all of the measurements in-store I don’t have the benefit of being able to measure the liquid by itself, or to weigh the empty containers for reference. Instead these numbers are intended to give veggie-oil fuel enthusiasts a ballpark figure for purchasing fuel from their local superstore.
The first stop on the tour was the sporting goods section where I picked up a five pound weight and a 25 pound fish scale. I used the weight to calibrate both the produce scale and fish scale before taking any measurements. Thanks to Emma for helping out!
With tools in hand I headed over to the automotive section to pick up a little motor oil and a one gallon gas can. I grabbed a one quart bottle of Havoline 5W30 and a five quart jug of the same.
| Havoline 5W30 | 1 quart | $1.97/unit | $7.88/gallon |
| Havoline 5W30 | 5 quart | $8.95/unit | $7.15/gallon |
After that, I moved to the food section of the store and picked out a one gallon jug of Great Value brand vegetable oil and a 1 gallon container of corn oil.
| Bulk Vegetable Oil | 1 gallon | $4.57/unit | $4.57/gallon |
| Bulk Corn Oil | 1 gallon | $4.96/unit | $4.96/gallon |
| CWP Veggie Oil | 48oz | $1.68/unit | $4.48/gallon |
| Crisco Canola Oil | 48oz | $1.84/unit | $4.91/gallon |
All of these I took over to the produce section and weighed them individually – again using the 5 lb. weight to ensure the scales were accurate.
| Products | Amount | Total | Ounces | Weight of a gallon |
| Vegetable Oil | 1 gallon | 8 pounds | 128 ounces | 8lbs |
| Corn Oil | 1 gallon | 8 pounds | 128 ounces | 8lbs |
| Motor Oil | 5 quarts | 9 pounds, 7 ounces | 151 ounces | 7.55lbs |
| Motor Oil | 1 quart | 1 pound, 15 ounces | 31 ounces | 7.75lbs |
After leaving Walmart I went to their gas station with my 1 gallon gas can. Using the fish scale, I was able to measure the gas can both empty and full.
| Empty Gas Can | 13 oz |
| Gas Can with 1.046 gallons | 7 lbs, 3 oz (115 ounces) |
| One Gallon of Gas weighs | 6.10 pounds (97.52 ounces) |
The results of this experiment were very interesting. I was surprised to learn that a gallon of gas weighs so much less than a gallon of vegetable or corn oil.
My husband and I have discussed these weights for years, but, of course, were not as industrious as yourself. Thank you for your contribution to our quandry.
Excellent work. Only other variable is heat but not quite so much of a factor and purity as well – bio grade can be a bit of a strange brew even with credentials.
Your experiment, while noble, is flawed by the fact that you did not subtract the weights of the containers from the gross weights of the oils, and you did not specify the grade or brand of “gas” you bought and did subtract the container weight from. And, spring scales are notoriously inaccurate!
Vegetable oil containers can be made from heavy or light weight plastics. Motor oil containers are mostly HDPE and can be various thickness, especially in the extrusion of the bottom of a gallon sized container, which can be up to 1/4 inch thick. In addition, you cannot be sure that the volumes were equal just because the labels said they were. Federal law allows a certain percentage variation in volume measure for various products. Food products can vary from the label by 5%.
Gasoline sold by various companies has various additive, methanol being a major one today. Gasoline can vary up to 1/2 pound per gallon depending on its contents. And of course gas is lighter than oil, it has lower carbon density; crude oil is heaviest, refined oils lighter, volatiles lightest. Think of it this way: methane, with one carbon, is a gas at room temp; octane with eight carbons, is liquid longer, but becomes gas easily. More carbon = more weight = more solid.
A good design would be to obtain a certified scale and a volumetric container that is also lab grade, then weigh the liquids in the same container, cleaning and taring between measurements. Additionally, the standard weights for most liquids are available on- line already and you would not run the risk of misinforming your audience! Good luck with future,”experiments”.
I forgot to mention temperature variations, since temp affects volume and volume affects mass. Vegetale oils average a specific gravity of .92, which means at any temperature they weigh 92% of the weigh tof water, or 8.3453 lbs per gallon times .92 equals 7.68 pounds per gallon vegetable oil. This will vary by carbon saturation.
Ciao, Ed
correction of volume & density for bulk sunflour oil at 15 deg.cent.
Thanks to Ed Brown for the refined calculations. I am now able to calculate the price per FLUID ounce of vegetable oil for my food coop based on buying a 35# container.
Ed, thank you for stealing the audience and bashing a post from 2006. Hopefully being a year after your posting will still be ‘acceptable’. This is a reasonable enough article for ball parking weights and measures for the average bio diesel brewer.
Thank you Ed for sharing your endless knowledge to the rest of the world, but even the crickets are tired from reading your post.
To the Author,
Thank you for getting away from your computer and to figure out the densities so others would be able to finish off rough calculations from home. Hrmm, will 4 caster wheels each rated at 750lbs work? I’m hoping so!