Conditioning (Cooking)
What conditioning does
Conditioning, often called cooking, is the heat-and-moisture step that readies flaked seed for the press. Applying controlled heat and adjusting moisture does several things at once: it ruptures more oil cells, lowers the viscosity of the oil so it flows more easily, helps small oil droplets coalesce into larger, more pressable masses, and adjusts the material to the plastic condition a press works best on. The result is that a well-conditioned seed gives up markedly more oil than an unconditioned one, which is why cooking is a standard step ahead of hot pressing and why traditional oil-making has always roasted or heated the seed.
Moisture and temperature: the two dials
Conditioning is governed by two dials — moisture and temperature — and both have a sweet spot. Moisture that is too high makes the oil hard to press and clarify and can cause the press to slip; too low, and cells do not rupture cleanly and the cake becomes hard to handle — so conditioning brings the seed to a target moisture, often in the region of 7–9% for pressing. Temperature likewise has a window: enough heat to rupture cells and lower viscosity, but not so much or so long that it scorches the seed and damages oil quality. The right settings depend on the seed, and they trade off yield against quality — which is exactly the balance a hot-press operator manages, and why cooking control is a core skill.
Cooking and the hot-versus-cold choice
Conditioning is also where the hot-versus-cold pressing decision plays out. Hot pressing deliberately cooks the seed to maximise yield and, for some seeds like sesame and groundnut, to develop flavour by roasting — accepting some loss of heat-sensitive character. Cold pressing minimises or skips cooking to keep the oil cool and preserve flavour and delicate components, accepting lower yield as the price. So the amount of conditioning is not just a technical setting but a market decision: cook for yield and a robust commodity oil, or keep it cool for a premium, flavour-led product. Either way, conditioning is the last preparation step before the flaked, cooked seed goes to the press.
Key figures (indicative)
| Parameter | Typical |
|---|---|
| Also called | cooking |
| Adjusts | moisture and temperature of the flakes |
| Conditioning temperature | ~65–70 °C with steam (to plasticize before flaking) |
| Target moisture | often ~7–9% for pressing |
| Effect | ruptures cells, lowers viscosity, aids coalescence |
| Trade-off | yield (hot) vs flavour (cold/minimal) |
FAQ
What is conditioning in oilseed processing?
Heating flaked seed and adjusting its moisture before pressing, so the oil cells rupture, the oil's viscosity drops and it coalesces — letting the press recover more oil. It is also called cooking.
Why does moisture matter before pressing?
Too wet and the seed presses poorly and the oil is hard to clarify; too dry and cells do not rupture cleanly. Conditioning brings the seed to a target moisture, often around 7–9%, for good pressing.
What is the difference between conditioning and roasting?
They overlap — conditioning is controlled heating and moisture adjustment for pressing yield; roasting is heating (often deeper) that also develops flavour, as for sesame or groundnut. Both are heat steps before pressing.
Does cooking increase oil yield?
Yes — controlled cooking ruptures more cells and lowers oil viscosity, so hot pressing recovers more oil than cold pressing. Cold pressing skips or minimises cooking to protect flavour, accepting lower yield.