Not every crude oil behaves the same way on a refining line, which is exactly why there isn’t one universal degumming method. Soybean oil separates its gums fairly easily with plain water. Canola and sunflower oil often fight back. Palm oil barely needs treatment at all. If you’ve been researching this topic and keep running into different method names — water degumming, acid degumming, super degumming, TOTAL degumming — without a clear explanation of how they actually differ, this guide is built to fix that.
We’re going to walk through every major type of degumming process used in commercial edible oil refining today, what each one actually does at a chemical level, where it fits best, and how to think about choosing between them if you’re designing or upgrading a refining line.
Why Multiple Types of Degumming Exist
Crude vegetable oil contains two fundamentally different categories of phospholipids, and this single fact is the reason the industry didn’t settle on one universal method:
- Hydratable phosphatides (HP) absorb water readily and separate out with simple hydration.
- Non-hydratable phosphatides (NHP) are bound to calcium and magnesium ions, resist plain water, and need acid, enzyme, or specialized chemical treatment before they’ll separate.
Different oils carry different ratios of HP to NHP, and different downstream refining routes (chemical refining vs. physical refining) demand different residual phosphorus targets. That combination is what drives the existence of multiple degumming types — each one is a response to a specific technical constraint, not just an alternative preference.
The Main Types of Degumming Process
1. Water Degumming
Water degumming is the industry’s baseline method and usually the first stage applied even when other treatments follow.
Process: Crude oil is heated to roughly 70–90°C and mixed with 1–3% soft water for 30–60 minutes under gentle agitation. The water hydrates the phosphatides, causing them to swell and become oil-insoluble, after which centrifugation separates degummed oil from the wet gum phase.
What it removes: Hydratable phosphatides only.
Typical residual phosphorus: 50–250 ppm — still too high for physical refining, which is why water degumming is frequently followed by a second treatment.
Best fit: Soybean oil, which is naturally rich in hydratable phospholipids and responds well to water alone as a first-stage treatment.
2. Acid Degumming
Acid degumming exists specifically to deal with the phosphatides that water degumming leaves behind.
Process: A small dose of concentrated acid — typically citric or phosphoric acid at around 0.05–0.2% — is dispersed into the oil. The acid chelates the calcium and magnesium bound to non-hydratable phosphatides, converting them into a hydratable form that water and centrifugation can then remove.
What it removes: Both hydratable and non-hydratable phosphatides.
Typical residual phosphorus: 10–30 ppm.
Best fit: Oils moving toward physical refining, where low phosphorus is essential before steam distillation/deodorization.
3. Enzymatic Degumming
Enzymatic degumming is the most technically advanced widely-adopted method, using phospholipase enzymes to biologically convert non-hydratable phosphatides rather than relying on acid alone.
Process: Crude or water-degummed oil is mixed with an aqueous phospholipase solution (commonly PLA1, PLA2, or PLC) at a controlled pH of roughly 4–6 and temperature of 50–70°C. Continuous high-shear mixing keeps the enzyme active at the oil-water interface for several hours, breaking down phospholipids into more water-soluble forms before centrifugal separation.
What it removes: Both hydratable and non-hydratable phosphatides, typically more completely than acid degumming alone.
Typical residual phosphorus: Under 10 ppm.
Best fit: Refiners prioritizing maximum oil yield, minimal chemical discharge, and high-value lecithin recovery — the enzyme cost is usually recovered through reduced oil loss and lower downstream caustic consumption.
4. Membrane (Dry) Degumming
Membrane degumming takes a physically different approach — separating gums by molecular size rather than by chemical hydration.
Process: Crude oil is passed through selective ultrafiltration membranes under pressure. Phospholipid molecules, being larger, are retained by the membrane while purified oil passes through with minimal added water or chemicals.
What it removes: Both hydratable and non-hydratable phosphatides, without a water-hydration step.
Best fit: Facilities aiming to minimize wastewater discharge or working toward zero-liquid-discharge operations; still more common at pilot and specialty scale than in mainstream commercial refining due to membrane fouling and capital cost.
5. Super Degumming
Super degumming is a refined variant of acid degumming, developed specifically to push residual phosphorus down to very low levels for physical refining.
Process: Water-degummed oil is treated with concentrated citric acid and a controlled amount of water, with hydration deliberately carried out at low temperature (below 40°C) to maximize phosphatide precipitation.
What it removes: Non-hydratable phosphatides with high efficiency.
Typical residual phosphorus: As low as 15–30 ppm.
Best fit: High-throughput physical refining operations where consistent, ultra-low phosphorus is a hard specification.
6. TOTAL Degumming
TOTAL degumming (also seen as “total degumming”) combines acid conditioning with a caustic buffering step, aiming to achieve both low phosphorus and reduced soap formation in a single sequence.
Process: Acid is added to the oil to condition non-hydratable phosphatides, followed by a small, carefully controlled dose of caustic soda to neutralize excess acid and support gum agglomeration, before final water washing and centrifugation.
What it removes: Broad-spectrum phosphatide removal with tighter control over final soap and phosphorus content simultaneously.
Best fit: Refineries running chemical (caustic) refining routes that want tighter downstream neutralization control without adding a fully separate processing stage.
7. Dry Degumming
Dry degumming is used almost exclusively for oils that are naturally low in gums to begin with.
Process: A small amount of phosphoric or citric acid is added directly to the oil, which then goes straight to bleaching — the bleaching earth adsorbs both the acid-treated gums and color pigments in a single combined step, followed by physical refining.
What it removes: The comparatively small phospholipid load found in naturally low-gum oils.
Best fit: Palm oil and similar oils processed through physical refining routes, where a full water/acid degumming stage isn’t economically justified.
Types of Degumming Compared
| Type | Removes | Water Use | Chemical/Enzyme Use | Residual Phosphorus | Best For |
|---|---|---|---|---|---|
| Water Degumming | Hydratable only | High | None | 50–250 ppm | Soybean oil (first stage) |
| Acid Degumming | Hydratable + non-hydratable | Medium | Citric/phosphoric acid | 10–30 ppm | Physical refining feedstocks |
| Enzymatic Degumming | Hydratable + non-hydratable | Medium | Phospholipase enzyme | Under 10 ppm | High-yield, low-waste plants |
| Membrane Degumming | Hydratable + non-hydratable | Low/None | None | Variable | Low-discharge, specialty plants |
| Super Degumming | Non-hydratable (high efficiency) | Medium | Concentrated citric acid | 15–30 ppm | Ultra-low P physical refining |
| TOTAL Degumming | Broad-spectrum | Medium | Acid + caustic soda | Low, controlled soap | Chemical refining lines |
| Dry Degumming | Low-gum oils | Low | Acid only | 5–15 ppm | Palm oil, physical refining |
How to Choose the Right Type of Degumming Process
Selecting a method isn’t a matter of picking the “best” one in isolation — it depends on four practical factors:
- Oil type and its natural phosphatide profile. Soybean oil’s largely hydratable gum content makes water degumming a reasonable starting point; canola and sunflower oils generally need acid or enzyme treatment added.
- Downstream refining route. Physical refining (steam distillation) demands much lower residual phosphorus than chemical (caustic) refining, which pushes plants toward acid, super, or enzymatic degumming.
- By-product strategy. If commercial lecithin recovery is a revenue goal, enzymatic or water degumming (which yield cleaner, more marketable gum phases) are usually preferred over methods that heavily chemically alter the phosphatide structure.
- Environmental and wastewater constraints. Plants under pressure to minimize effluent increasingly look at membrane or enzymatic routes over high-water-volume water degumming.
Expert Tips for Selecting a Degumming Type
- Test your specific crude oil, not industry averages. Phosphatide ratios shift with crop season, seed variety, and storage conditions — the “typical” numbers for an oil type are a starting point, not a guarantee.
- Think in stages, not single methods. Most commercial plants combine water degumming as a first stage with acid or enzymatic treatment afterward rather than relying on one method alone.
- Match your degumming type to your refining route early in plant design. Retrofitting a chemical refining line to hit physical-refining-grade phosphorus levels later is far more expensive than designing for it upfront.
- Factor in lecithin economics before ruling out enzymatic degumming on cost. The premium for enzymes is frequently offset by better yield and a higher-value by-product stream.
Common Mistakes When Choosing a Degumming Type
- Defaulting to water degumming for every oil. It works well for soybean oil but consistently underperforms on canola, sunflower, and other NHP-heavy oils.
- Ignoring the target refining route when selecting a method. Choosing a degumming type without confirming whether the line runs chemical or physical refining downstream leads to phosphorus specs that don’t match process needs.
- Underestimating water hardness. Hard water introduces calcium and magnesium that can work against non-hydratable phosphatide removal instead of helping it.
- Treating gum recovery as an afterthought. The method chosen affects how usable and valuable the recovered gums are for lecithin production — this should be part of the method decision, not a downstream surprise.
- Skipping trial runs before full-scale commitment. Given how much phosphatide ratios vary by source, running a small-batch trial before committing plant-wide dosing rates prevents costly recalibration later.
Frequently Asked Questions
What are the main types of degumming process used in edible oil refining?
The main types are water degumming, acid degumming, enzymatic degumming, membrane degumming, super degumming, TOTAL degumming, and dry degumming — each suited to different oil types and refining routes.
Which type of degumming is used for soybean oil?
Soybean oil is typically treated first with water degumming, since it’s naturally high in hydratable phospholipids. Many refiners follow this with acid or enzymatic treatment to reach lower phosphorus targets.
What type of degumming is best for palm oil?
Palm oil, being naturally low in gums, is generally treated with dry degumming, where a small acid dose is followed directly by bleaching rather than a separate water-based stage.
Is enzymatic degumming a type of chemical degumming?
No. Enzymatic degumming uses biological catalysts (phospholipase enzymes) rather than acid chemistry alone, though it’s often used alongside minor pH adjustment. It’s generally classified as its own category distinct from acid degumming.
What’s the difference between acid degumming and super degumming?
Super degumming is essentially an optimized form of acid degumming, using more concentrated citric acid and lower hydration temperatures to achieve significantly lower residual phosphorus than standard acid degumming.
Can more than one type of degumming be used in the same plant?
Yes, and it’s common practice. Many refineries run water degumming as a first stage and follow it with acid or enzymatic degumming to reach the phosphorus levels required for their specific refining route.
Conclusion
There’s no single “correct” degumming method — there’s only the right method for your oil, your refining route, and your operational priorities. Water degumming remains the reliable starting point for phosphatide-rich oils like soybean, acid and super degumming step in where non-hydratable gums resist simple hydration, enzymatic degumming offers the cleanest yield-to-cost balance for plants chasing efficiency, and dry degumming keeps naturally low-gum oils like palm oil moving efficiently through physical refining. Understanding these distinctions isn’t just academic — it’s what separates a refinery running on outdated assumptions from one engineered around the oil it’s actually processing.
Not Sure Which Degumming Type Fits Your Plant?
Fostechno engineers turnkey edible oil processing plants with the right degumming method built into the design from day one — matched to your specific oil type, capacity, and target refining route. From oilseed pre-treatment through degumming, neutralization, bleaching, and deodorization, our process engineers handle plant design, equipment selection, and installation end-to-end.
Get in touch with Fostechno for a process design and cost estimate matched to your oil type and production goals.
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