Instant coffee is made through a process that extracts the soluble coffee compounds from roasted coffee beans and then dries them to form a powder or granules. There are two main methods of producing instant coffee: spray-drying and freeze-drying.
1. Spray-Drying Process:
- Brewing: Coffee beans are roasted and brewed in large batches to create a strong, concentrated liquid coffee.
- Atomization: The coffee extract is sprayed into a chamber of hot air at around 480 °F (250 °C). The heat causes the water in the coffee to evaporate quickly.
- Drying: As the liquid evaporates, the remaining coffee solids fall as small, dry particles or powder. These are collected as instant coffee.
2. Freeze-Drying Process (more expensive but preserves flavor better):
- Concentration: The brewed coffee is concentrated through evaporation.
- Freezing: The concentrated coffee liquid is frozen at very low temperatures, typically around −40 °F (−40 °C).
- Sublimation: The frozen coffee is placed in a vacuum, where the ice is directly converted into vapor (without turning into liquid) through sublimation. This leaves behind solid coffee granules.
- Granulation: The freeze-dried coffee is broken into granules that can be dissolved in water to make instant coffee.
Both methods produce a coffee that can be quickly rehydrated with hot water, making it convenient for consumers.
