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Yellow Grease, Used Cooking oil and Waste Vegetable Oil

So what is the difference between UCO, WVO, SVO,  and Yellow Grease?

Yellow Grease is a commodity produced in the United States, as well as other countries with established Rendering Industries, that is produced by a recognized rendering process and is typically comprised of used cooking oil and often contains rendered low quality animal fats such as tallow, poultry or lard.


Generally yellow grease must meet the following specification: FFA max 15% and MIU 2%, often with 1% max water. FAC (color) and Titer (melting temp) may also be defined and typically assist with determining and/or limiting amount of rendered animal fats versus UCO is present.  MIU of 2% or below is commonly referred to as "clean and dry".  Pesticides and PCB testing/analysis may also be required for animal feed market.

As a fully processed and rendered product, yellow grease is the appropriate choice for animal feed and ingredients.  Part of the rendering process is heating to a temperature for a period of time sufficient to sterilize the product, which is an important consideration for animal feed and may not be accomplished with used cooking oil processing as described below.

Pricing:  Generally yellow grease and used cooking oil are the lowest priced fats when compared to fresh oils and animal fats.  As a recognized and defined commodity, along with fresh oils and animal fats, yellow grease has a variety of indexes reporting market price.  Most are available by paid private subscriptions, but limited information is available for free from the United States Department of Agriculture AMS report here.


When prices for yellow grease are indexed and published, one should consider whether the product meets the yellow grease specification and rendering requirements.  if it does not, then in our opinion, this is not "yellow grease" per se, rather the product is processed or refined UCO/WVO and these yellow grease indices should not be referenced solely as the basis for determining price, especially if filtration, reduced animal fat or low FFA is present in the product.  All of these attributes increase the value of the product and one can typically expect to pay more for this than for yellow grease.

Used Cooking Oil (UCO): Used cooking oil is waste or spent cooking & frying oils collected from commercial food factories, restaurants, arena's, casinos, schools, bakeries, etc. While the majority of used cooking oils are vegetable based, by no means should UCO be considered "waste vegetable oil" as there is inevitably some level of animal fat in UCO, which is naturally derived from the cooking process, and of course some restaurants cook in fats rather than oils. Generally UCO should not be considered yellow grease as it may not be fully rendered or meet the specification commonly associated with yellow grease.


 Traditional uses for UCO have been to produce yellow grease for animal feed, limited use as part of a fuel mixture for boilers or kilns, or simply dispose of by landfill as part of a waste stream. However, over the past decade, demand for UCO has increased significantly largely due to the biofuels/biodiesel market place.  Increasingly seen as a sustainable, recycled and non-food competiting product (food vs. fuel debate), used cooking oil has become the socially responsible, sustainable,  lower cost, and often only locally produced feedstock readily available to biodiesel producers.  In addition to the lower cost and sustainable nature of the feedstock, certain state and national government agencies have provided additional or increased incentives for biodiesel produced from used cooking oil.  UCO is a recognized feedstock for USA's Renewable Fues Standard (RFS2) and thus biodiesel produced from UCO can qualify for RIN's tax credits.  California's Low Carbon Fuel Standard ("LCFS") takes this even further and recognizes UCO/YG as one of the lowest Carbon Intensity ("CI") feedstocks, and thus UCO biodiesel qualifies for a significantly higher credit value than fresh oils, animal fats, etc.  Another example is the EU/EC provides a "double count" benefit for biodiesel produced from UCO, meaning every liter of UCO biodiesel used toward meeting a biodiesel mandate can be "double counted" as two liters.

UCO products vary greatly.  When originally collected, product may be completely unprocessed (raw) and generally will contain elevated impurities, water and free fatty acid levels. In severe cases low grade unprocessed UCO product may contain bags, gloves, plastic, towels, and any other items which find their way into the collection bin.  Additionally unscrupulous persons may dump used motor oil or paint/solvents in to the collection drum which effectively contaminate the oil and render it useless. The picture to the right at the top is very low quality UCO collected from restaurants and has no processing done to it. FFA was about 17% and has increased to 22 over time. Water contents is about 30% and is one of the causes for increasing FFA (water and heat can increase FFA by 1% or more per week). Pictured in the middle on the lower right is another UCO product. This is collected from closed loop restaurant oil systems and tends to be higher quality than UCO collected from drums and barrels, but has significant levels of animal fat and/or hydrogenated/saturated fats and oils. This product shows clear veg oil on top, and bottom layer of saturated/hydrogenated fats and oils. FFA is about 6-9% on this and MIU about 4%. This material comes from one of the main national restaurant cooking oil automation companies.

Waste Vegetable Oil (WVO):
WVO is simply another name for used cooking oil (restaurant grease) or in some cases may be used to refer to off spec or expired fresh oils that cannot be used/marketed as intended. WVO is generally used to refer to used cooking oils that are primarily vegetable oil based and have minimum or no animal fats from cooking process. Oil may or may not be processed and will have variable specifications for MIU and FFA. Pictured on the lower right is a product which has been skimmed to remove animal fats and saturated/hydrogenated fats and oils, and finely micron filtered.  This would be considered a refined waste vegetable oil product. In general used cooking oil cannot be guaranteed 100% vegetable oil as almost all cooking oils have some level of animal fat content derived from the cooking process.

Straight Vegetable Oil (SVO): SVO is a reference to highly refined/polished UCO or refined fresh oils which are used "straight" to fuel diesel engines.  In this case, oil is not processed into biodiesel, rather oil is (generally) pre-heated to reduce viscosity and is then injected directly as diesel fuel.  UCO/WVO that has not been processed to remove particulate and water is not suitable for use as SVO.  Oils with high FFA are also not advisable to use as SVO as this may damage diesel equipment like injectors. People running SVO generally have some type of conversion kit installed which heats oil, either in tank, by injector/fuel line, or both. The picture on the right, at the bottom, is an example of what SVO quality UCO looks like. This product has FFA about 1-5% max and MIU generally <1%.

Uses for UCO, SVO and Yellow Grease: There are many uses for UCO and yellow grease, with 2 primary markets- 1st is for processing into biofuels (svo or biodiesel) often referred to as "feedstock". The second and more traditional use is for blending into animal feed for cattle and poultry as yellow grease (only in-spec yellow grease with FFA 15% or below and MIU <2% with impurities max .25% is accepted in feed markets), Additional uses include dust suppression (roads, construction and drilling), and as furnace and boiler fuel, and increasingly green chemistry.

Specification Requirements:
Animal Feed: Yellow Grease must have 15% Maximum FFA, MIU <2% (with water max 1% and impurities .25%). Animal feed markets typically will not accept specifications outside this range. Most biodiesel producers will not accept FFA levels above 10%. Product should be screened to remove debris, sludge, sediment, etc. If you are filtering, we encourage filtration of 200 micron max, this is more than enough to produce clean product.  Keep in mind, filtration does not equate to dry material, product must be properly heated and settled/skimmed to remove moisture (decanted).

Biofuels feedstock: For biodiesel production, specification varies somewhat by producer and equipment. Generally FFA max 10%, but FFA 5% and below is ideal. MIU should be below 2%. Again filtration to 200 micron is more than acceptable but filtration generally is not required. 

PAER is active in the used cooking oil and yellow grease sourcing and trading business. As a trading company, PAER is a direct buyer of product, not a broker.  We currently source from a variety of US locations, spanning east and west coasts, and we serve markets in North America, Europe and the South Pacific.


In addition to our trading business, PAER works closely with a variety of UCO collection and processing companies to establish and develop their businesses while providing competitive reliable & timely payments for their UCO payments. Such activities take form of partnerships, joint ventures or invested ownership stake.


PAER holds a valid USDA license to import UCO into the US, fully compliant with recent changes in USDA controlled substance laws regarding UCO.  We welcome contact from both buyers and suppliers, you can contact us here.

COA Requirement:

In order for PAER to consider any UCO or yellow grease offers, it is mandatory supplier provides a third party certificate of analysis to PAER. We will not purchase product without a current, representative COA. You can view a sample COA below. At the very least we need to see FFA and MIU for biofuels feedstock. Additional tests required may include iodine, peroxide, PCB's and pesticides (generally required for animal feed markets).

Example of COA is below. At minimum we need to see FFA, MIU test results.


Shipping and logistics:
PAER has a variety of logistics solutions we can provide to assist with the procurement and transportation of your product. For international import/export PAER generally ships by flexi tank in 20 foot dry van container, or by ISO tank. PAER does not ship international product in drums or IBC totes.

Flexitank Load

ISO Tank

275 gallon totes are convenient
for small deliveries and storage for low volume users. However, California law requires a grease hauler license for transportation of UCO, so this has made transport and delivery of small volumes product limited and expensive.

Totes can be used in 40 foot cargo container to ship about 20 MT, but cost of totes makes this option more expensive than shipping by flexitank, and additionally limits the processing plants to those that have many extra totes and a forklift for loading.  PAER encourages the use of flexitanks for international shipments.

For regional delivery of larger supply, PAER can arrange tanker truck delivery (generally minimum 6,000 gallons)

PAER UCO Links & Info

CalOilSampleMix.jpg (85426 bytes)
Quality California
Low FFA UCO Available.

Page Topics:

Yellow Grease

Used Cooking Oil

Waste Vegetable Oil

Straight Vegetable Oil

Uses for used oils

Certificate of Analysis


Shipping and Logistics

UCO collection & recycling service Greater Toronto Area Canada

UCO Examples


Above, low grade "raw" UCO collected from restaurants. FFA 20%+, MIU 30%+


Above, mid grade UCO 50 micron filtration,
FFA <9%, MIU <5%,

some saturated and hydrogenated fats and oils present on bottom 30%.


Above, SVO quality UCO/WVO, settled and skimmed to recover only fine, clear vegetable oil, then filtered down to 5 micron. FFA 1-5% max,
MIU <1% to 2% max.


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