Overview
What Is Distillers Corn Oil (DCO)?
Distillers corn oil (DCO), also known as corn oil from ethanol production or distillers dried grains oil, is extracted from the stillage produced during corn grain fermentation for ethanol. After fermentation and distillation, the residual mash (wet distillers grains) is centrifuged or extracted using mechanical presses or hexane to yield a dark, high-FFA oil with a high proportion of linoleic acid.
DCO is not a virgin vegetable oil, it is a co-product of corn ethanol fermentation (technical corn oil). Under EU RED III it is not listed in Annex IX Part A or Part B, so it does not receive Annex IX double-counting or fall under the Part B 1.7% transport cap. It remains a widely traded lipid for HVO, FAME and HEFA, with strong economics under US RFS D4/D5 pathways.
The United States is the world's dominant DCO producer, with annual availability estimated at 2.5-3 million tonnes from the Corn Belt ethanol sector (Iowa, Illinois, Nebraska). DCO is also a major feedstock in the US RFS system, qualifying for both D4 Biomass-Based Diesel and D5 Advanced Biofuel RINs.
Key processing consideration: DCO's high FFA content (15-35%) requires an acid esterification pre-treatment step before FAME (biodiesel) production, or a dedicated pre-treatment unit before hydroprocessing for HVO/SAF applications.
Key Advantages
Why Distillers Corn Oil for Biofuels?
Not Annex IX Listed
Technical corn oil is outside Annex IX A/B: no Annex IX double-counting and no Part B 1.7% cap. Confirm crop-cap treatment on the PoS. Strong US RFS D4/D5 value.
77-85% GHG Savings
RED III default value significantly higher than crop-based oils. Per tonne of DCO processed into HVO, approximately 2.4 tonnes CO₂e avoided vs fossil diesel.
D4/D5 RIN Value (US Market)
DCO biodiesel earns D4 Biomass-Based Diesel RINs. DCO HVO may earn D5 Advanced Biofuel RINs. Critical economic driver for US biofuel producers under RFS2.
Price Competitive
DCO typically trades at a discount to refined vegetable oils (RBD soy, RBD sunflower) due to high FFA content and processing complexity, attractive total-cost-in feedstock economics.
Technical Data
Quality Specifications
Typical quality parameters for Distillers Corn Oil (DCO) as supplied by Suat Fuels. Batch-specific CoA available on request.
| Parameter | Typical Value | Limit | Test Method |
|---|---|---|---|
| Free Fatty Acids (FFA) | 15-25% | max 35% | AOCS Ca 5a-40 |
| Moisture, Impurities & Unsaponifiable (MIU) | 1-3% | max 4% | AOCS Ca 2b-38 |
| Iodine Value | 110-130 g I₂/100g | - | AOCS Cd 1d-92 |
| Phosphorus | 50-200 ppm | varies by buyer | EN 14107 |
| Sulfur | 10-30 ppm | max 50 ppm | EN ISO 20846 |
| Water Content | 0.5-2% | max 3% | EN ISO 12937 |
| Flash Point | >100°C | - | ISO 2592 |
| Density at 20°C | 0.915-0.925 kg/L | - | EN ISO 3675 |
| Linoleic Acid (C18:2) | 40-60% | - | EN ISO 5508 |
| Colour (Gardner) | 8-14 | - | AOCS Td 1a-64 |
Compliance
Regulatory Status & Certifications
EU RED III Status (Ethanol Co-Product / Technical Corn Oil)
- Not listed in Annex IX Part A or Part B, no Annex IX double-counting and not under the Part B 1.7% transport energy cap
- Treated as an "other" / process co-product feedstock; member-state crop-cap treatment can vary, confirm on PoS
- ISCC EU chain-of-custody available, Suat Fuels holds active ISCC EU and ISCC CORSIA licences
- Usable in HEFA/HVO pathways; Annex IX mandate value differs from UCO or Cat 1&2 fats
- US market: D4 Biomass-Based Diesel RINs (FAME) and potentially D5 Advanced Biofuel RINs (HVO)
End Uses
Applications
HEFA-SAF
Hydroprocessed DCO for HEFA-SAF pathways. Not Annex IX listed, so mandate compliance value differs from Part A/B lipids; still widely used where economics and PoS allow.
HVO Renewable Diesel
Requires FFA pre-treatment but delivers high-quality EN 15940 paraffinic diesel. Used extensively in US renewable diesel refineries.
FAME Biodiesel (DCME)
Acid esterification of FFA followed by base transesterification. D4 RIN eligible in US. EN 14214 compliant SME/FAME blending component.
US Biofuel Industry
Primary feedstock for US biomass-based diesel facilities. Several US HVO/FAME plants designed specifically for high-FFA feedstocks including DCO.
Supply Geography
Origins & Availability
DCO is produced almost exclusively in the United States Corn Belt, where large-scale dry-mill ethanol plants extract corn oil from distillers grains during the drying process. Major production states: Iowa, Illinois, Nebraska, Indiana, Minnesota. European DCO availability is limited (Germany, Hungary have some grain ethanol production). Suat Fuels sources US DCO in both container and bulk quantities with full ISCC documentation for EU and US buyers.