Degummed vs Undegummed Oil

At a glance

What the "gums" are

The whole comparison turns on one class of compounds: phosphatides, also called phospholipids or simply gums. They occur naturally in the seed and come out with the oil during pressing and extraction, so every crude oil contains them — soybean oil notably so. The problem is that phosphatides are surface-active and partly water-loving: in the oil they hold onto water and trace metals, cause the oil to look cloudy, and settle out as a sticky sludge over time. Left in the oil they foul heat exchangers, promote oxidation (the trapped metals are pro-oxidants), and interfere with every later refining step. Removing them is therefore the logical first move, and it is exactly what degumming does.

What degumming removes — and how

Degumming removes the phosphatides by making them separable from the oil. In water degumming, a little water is mixed into the warm oil; the hydratable phosphatides absorb it, swell into a heavier hydrated gum phase, and are spun out in a centrifuge. Some phosphatides are non-hydratable (bound to calcium and magnesium) and will not respond to water alone, so acid degumming adds a small dose of phosphoric or citric acid to convert them into a removable form — the two approaches are compared in water vs acid degumming. Either way the output is a degummed oil plus a wet gum phase. What degumming does not do is remove free fatty acids, colour or odour — those are the jobs of later refining steps. Degumming is specifically the removal of the gums, and undegummed oil is simply oil that has not yet had this done.

Why degummed oil stores and ships better

The most practical reason to degum is stability in storage and transport. In undegummed oil, the phosphatides slowly settle out as a gum/sludge layer at the bottom of a tank or drum, which is unsightly, wastes oil trapped in the sludge, and can foul pumps and lines. The trapped metals also catalyse oxidation, so undegummed oil tends to go off faster. Degummed oil, with the gums already removed, stays clearer and more stable, which is precisely why oil that must be stored for a while, shipped long distances or traded is usually degummed first. It is easier to handle, holds its quality, and arrives in predictable condition — real advantages when oil moves between a crushing plant and a distant refinery.

Crude and degummed as trade grades

These are not just lab states — they are commercial grades. Crude oil (undegummed) and degummed oil are both traded, and for soybean in particular crude degummed soybean oil is a well-known international trade grade: the oil is degummed at origin so it ships and stores reliably, then fully refined at destination. A buyer chooses the grade to suit their setup — a refiner with degumming capacity might buy cheaper crude and degum it themselves, while one buying oil for storage or resale will want it degummed. The price difference reflects the one processing step and the handling advantage, so "degummed vs undegummed" is often really a make-or-buy and logistics decision as much as a technical one.

Lecithin — the valuable by-product

Degumming also creates value on the gum side. The wet gums removed from the oil are not just waste: they are the source of lecithin, an emulsifier widely used in food and industry, and soybean degumming is the classic commercial source. So a plant that degums can recover and sell lecithin from a stream it had to remove anyway, improving the economics of the whole operation. Undegummed oil, by definition, still has that potential value locked inside it as dispersed phosphatides. This by-product angle is one more reason degumming is treated as a worthwhile step rather than a cost — it removes a problem from the oil and yields a saleable product, which is a large part of why crude oils that are rich in phosphatides are so commonly degummed at the crushing plant.

Enzymatic degumming — a modern third route

Beyond water and acid degumming, many modern plants use enzymatic degumming, and it changes the calculus in a way worth knowing. Instead of only hydrating or acid-treating the gums, an enzyme is added that acts on the phosphatides directly, converting them into forms that separate cleanly from the oil. Its headline advantage is yield: enzymatic degumming can actively free neutral oil that would otherwise be trapped in the gum phase and lost, so it often recovers more oil than water degumming while still producing a low-phosphorus, refinery-ready oil. It also tends to use fewer harsh chemicals and can suit physical refining, which demands a very low residual phosphorus that enzymatic treatment can reach. So while the basic "degummed vs undegummed" distinction is unchanged — gums out or gums in — the method chosen affects how much oil survives the step, and enzymatic degumming is increasingly picked precisely because it protects yield while delivering a well-degummed oil ready for the rest of refining.

When undegummed oil is acceptable

None of this makes undegummed oil "bad" — it just means the gums have not been removed yet. The sensible case for keeping oil undegummed is when it will be refined promptly on the same site: since degumming is the first step of refining anyway, a plant that presses and refines in one integrated line simply feeds crude oil straight into its own degumming stage, with no need to produce and store a separate degummed grade. In that setup, degumming as a distinct saleable step adds nothing. Undegummed oil is also cheaper to buy for exactly this reason. The decision, then, is about timing and logistics: degum now if the oil must be stored, shipped or traded and you want the by-product and stability; leave it undegummed if it goes straight into refining under your own roof. Either way the gums come out before the oil is finished — the only question is where and when.

The bottom line

Because degumming is simply the first step of refining pulled forward, "degummed vs undegummed" is less a rivalry than a staging choice. Degummed oil is the grade for the real world of tanks, ships and contracts: stable, clear, ready to refine, with lecithin captured. Undegummed crude is the raw, cheaper form that belongs inside an integrated crush-and-refine plant where the gums will be removed within hours. Judge them not by which is "better" but by what happens next to the oil — and remember that a well-degummed feed makes every later refining step, from neutralizing to bleaching, run cleaner and with lower loss.

Verdict — which should you choose?

FAQ