2-Phase vs 3-Phase Centrifuge Olive Oil Mills

2-Phase System

A 2-phase decanter separates the olive paste into:

• Olive oil
• Wet pomace (containing solids and most of the vegetation water)

Advantages

• Much lower water use
• Reduced wastewater disposal costs
• Better retention of antioxidants and polyphenols
• Often associated with higher-quality premium oils

Disadvantages

• Pomace contains more moisture (typically 55–70%) making it heavier
• Transportation and further processing of pomace can be more expensive

3-Phase System

A 3-phase decanter separates the paste into:

• Olive oil
• Solid pomace
• Water (olive mill wastewater)

Water is added to facilitate separation.

Advantages

• Drier pomace, easier to handle and transport
• Can provide stable operation with certain olive varieties and processing conditions
• Historically common in many large mills

Disadvantages

• Higher water consumption.
• Produces substantial wastewater requiring treatment or disposal
• Some valuable phenolic compounds are lost into the wastewater stream
• Oil Quality Differences

Modern studies generally find that 2-phase systems tend to produce oils with:

• Higher phenolic content
• Greater oxidative stability
• Stronger fruity and bitter sensory characteristics

However, olive variety, fruit condition, harvest timing, and malaxation settings often have a larger impact on oil quality than the choice between 2-phase and 3-phase extraction.

Current Industry Trend

Many new mills in olive-producing regions such as Spain, Italy, Turkey, and Greece have moved toward 2-phase systems because of:

• Water scarcity concerns
• Environmental regulations
• Demand for high-phenolic extra virgin olive oil

Which Should You Choose?

• Choose 2-phase if your priority is premium oil quality, water conservation, and lower environmental impact
• Choose 3-phase if wastewater management is available and drier pomace is important for your operation or downstream pomace processing

For a small-to-medium mill processing under 5 tons/hour, a modern continuous mill with a 2-phase decanter is often considered the most common choice today for producing high-quality extra virgin olive oil.