Cold oil press machine and hot oil press machine are two common vegetable oil extraction equipment, they have significant differences in process, oil characteristics, application scenarios and so on.
Comparison of process principle
Cold oil press machine
- Temperature control: the temperature of the whole pressing process is ≤60℃ (some precision equipment is controlled below 40℃).
- Pre-treatment process: the raw materials only need to be cleaned and dehulled, without heating or steaming.
- Pressing method: physical pressure (screw press mainly) is used for direct oil extraction, without chemical treatment.
- Typical applicable raw materials: high oleic acid oilseeds (such as olive, walnut, linseed), heat-sensitive raw materials (such as perilla seed).
Hot oil press machine
- Temperature control: The temperature of raw material pretreatment stage reaches 120-180℃, and the pressing temperature is about 80-130℃.
- Pretreatment process: Key steps include high temperature steaming/roasting (destroying cell walls), tempering (adjusting moisture to 8-12%).
- Pressing method: High temperature combined with physical pressing, some processes may include leaching to increase the oil yield.
- Typical raw materials: low oil content or flavor-enhanced raw materials (e.g. soybean, peanut, sesame).
Comparison of Oil Characteristics
| Indicator | Cold pressed oil | Hot pressed oil |
| Nutritional | Retain more than 90% of natural vitamins and polyphenols | Thermal nutritional loss of 30-50% (e.g. VE, sterols) |
| Flavor characteristics | Light original flavor, plant aroma | Strong burnt flavor (product of Meladol reaction) |
| Color and transparency | Light color, high transparency | Dark color, may contain suspended colloids |
| Oxidative stability | Need to add antioxidants (rapid increase in acid value) | Natural antioxidants retain more (e.g. sesamol) |
| Impurity content | ≤0.1% (requires fine filtration) | Gum, high phospholipid content (requires degumming and refining) |
Comparison of economic and technical indicators
Oil yield
Hot pressing increases oil yield by 15-30% compared with cold pressing (soybean oil yield 18-20% for hot pressing vs. 12-15% for cold pressing).
Cost of energy consumption
Energy consumption per unit of hot pressing is 2-3 times higher than that of cold pressing (steaming and stir-frying process accounts for more than 60% of energy consumption).
Equipment investment
The cost of cold pressing unit (including low temperature filtration system) is 20-40% higher than that of hot pressing unit with the same capacity.
Production cost
The comprehensive cost of cold pressed oil is 30-50% higher (low oil yield + fine filtration loss).
Suggestions for application scenarios
Preferred scenarios for cold pressing
- Pharmaceutical/health care oil (e.g. sea buckthorn seed oil, evening primrose oil)
- High-end edible oil market (premium of cold pressed olive oil can be up to 200%)
- Bioactive components need to be preserved (e.g. alpha-linolenic acid in flaxseed)
- Regions with strict environmental requirements (no high temperature exhaust emissions)
Scenarios where hot pressing is preferred
- Bulk oilseed processing (large-scale production of soybean and rapeseed)
- Edible oil requiring special flavor (small milled sesame oil)
- Industrial oil production (frying oil with high smoke point)
- Raw materials containing anti-nutritional factors (cottonseed needs high temperature to destroy cotton phenol)
Technological development trends
Cold pressing technology innovation
Ultrasonic pre-treatment and low-temperature enzyme digestion technology can increase the oil yield to a level close to that of hot pressing.
Optimization of hot pressing process
Precise temperature control technology (infrared thermal imaging + PLC control) reduces nutrient loss to less than 15%.
Mixing process application
Segmented processing (e.g., peanuts are first broken down at low temperatures and then moderately warmed to enhance flavor).
Conclusion Recommendations
- Health-oriented market: Prefer cold-pressing process, which is in line with clean-labeling trends, albeit at a higher cost
- Traditional flavor-demanding market: hot pressing is not replaceable, and refining equipment is needed to improve oil quality
- Bulk oilseed processing: hot pressing + leaching combination is recommended to balance cost-effectiveness.