Yellow grease is the commercial industry term for used cooking oil that meets specific quality standards — most importantly, a free fatty acid (FFA) content below 15%. Clean fryer oil from restaurants is the primary source. Demand has surged in recent years because yellow grease is the preferred feedstock for renewable diesel and sustainable aviation fuel (SAF) production.
The definition in plain language
"Yellow grease" is a trade classification, not a product name you would see on a menu. When a restaurant's used cooking oil is collected, filtered, and tested, it becomes yellow grease if it meets the commercial specifications set by buyers: FFA content under 15%, moisture below a certain threshold, and relatively low levels of impurities. Oil that does not meet these specs is classified as brown grease, which has far fewer uses and a much lower value.
The color reference is literal — clean, commercially usable grease has a golden-yellow appearance. Oil that has broken down badly or been contaminated with food waste, water, or trap grease darkens toward brown or black, which is one of the reasons quality specs matter.
Where yellow grease comes from
The vast majority of yellow grease originates in commercial kitchens — restaurants, fast food chains, institutional cafeterias, food manufacturers, and similar operations that use deep fryers or high-volume cooking equipment. A single full-service restaurant might generate anywhere from 40 to 400 gallons per month, depending on menu and volume.
After pickup by a collection service, the oil typically goes through a multi-step process: settlement to separate water and solids, filtration to remove fine particulates, and sometimes additional processing to reduce FFA content. By the time it reaches a refiner, it is a standardized, tradeable commodity.
Why the value has been climbing
For most of the last century, yellow grease was primarily used in animal feed and as an input for oleochemicals (soap, cosmetics, industrial products). Its price reflected that — useful, but not high-value.
Three things changed this:
- Renewable diesel production scaled up in North America and Europe, driven by low-carbon fuel standards and blending mandates. Renewable diesel refineries need a feedstock, and yellow grease is among the lowest-carbon options available.
- Sustainable aviation fuel (SAF) emerged as a major buyer. Airlines facing emissions regulations have committed to SAF blends, and a significant portion of current SAF comes from used cooking oil feedstock.
- Regulatory incentives shifted in favor of domestic UCO. In the U.S., tax credits and Renewable Identification Number (RIN) mechanisms reward low-carbon feedstocks, and policy changes have placed a premium on oil collected domestically rather than imported.
The result: yellow grease pricing has climbed substantially compared to historical levels, and restaurants that generate significant volumes are in a better position than ever to be paid meaningfully for their oil.
What this means for your restaurant
For a restaurant operator, three practical implications come out of this market context:
First, your oil has real value. Many restaurants still pay for grease pickup or give it away for free, unaware that their volume qualifies them to be paid by the gallon.
Second, oil quality matters. Oil that is heavily contaminated with water, food waste, or trap grease will not qualify as yellow grease and may be worth much less — or nothing. Keeping your fryer oil separate from other kitchen waste is the single most important thing you can do to preserve its value.
Third, who you sell to matters. Established collectors sell directly into the refining supply chain and can offer rates tied to market conditions. Brokers and middle-layer aggregators take a cut. Independent collectors without refinery relationships may offer less because they have fewer buyers.
Key takeaway
Yellow grease is clean, commercial-grade used cooking oil with FFA below 15%. It is the feedstock that powers renewable diesel and SAF production, and demand — along with the price restaurants can command for it — has grown substantially. Keeping your fryer oil clean and choosing a collector with refinery relationships are the two biggest factors in realizing that value.