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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 in the United States that is produced by rendering companies and is typically comprised of used cooking oil and may contain rendered animal fats such as tallow, poultry fat or lard. Generally yellow grease must meet the following specification: FFA max 15% and MIU < 2% with 1% max water.  MIU of 2% or below is commonly referred to as "clean and dry".  When prices for yellow grease are indexed and published, one should consider whether the product meets the yellow grease specification.  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 oils collected from food factories, restaurants, bakeries, etc. and is also commonly referred to as waste vegetable oil, although it may contain significant amount of animal fats from cooking process.  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 hydrogonated/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%.

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/hydrogonated fats and oils, and finely micron filtered.  This would be considered a refined waste vegetable oil product.

Straight Vegetable Oil (SVO): SVO is a reference to refined/polished UCO or refined fresh oils which are used to fuel diesel engines.  In this case, oil is not processed into biodiesel, rather oil is (generally) heated to reduce viscosity and is then used 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 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 biostock. 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% is accepted in feed markets), Additional uses include dust suppression (roads, construction and drilling), and as furnace and boiler fuel.

Specification Requirements:
Animal Feed: Yellow Grease, must be FFA 15% Maximum, MIU <2% (with water max 1%). Animal feed markets will not accept specifications outside this range. Most biodiesel producers will not accept FFA levels above 10%. Product should be filtered to remove debris, sludge, sediment, etc. We encourage filtration of 100 to 200 micron. Clean and dry

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%, and additionally filtration to 5 micron is ideal, but up to 100 micron is generally acceptable.


PAER is active in the used cooking oil and yellow grease sourcing and trading business.  We currently source from several US locations, both east and west coasts, and we serve markets in North America, Europe and the South Pacific. 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 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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