What is“Soluble Coffee”?

sol·u·ble (sŏl'yə-bəl) adj.
1) That can be dissolved, especially easily dissolved.
- The American Heritage® Dictionary of the English Language.

Retail marketed as "Instant Coffee", it is the solubility of these coffees that gives them their distinction over roasted and ground coffee. After green coffee is roasted and brewed, the extract is then processed into various types of soluble coffees.

Spray-dried:

Spray drying produces fine, rounded particles. Due to the cost effectiveness of spray drying, the greatest variety of soluble coffees is produced using this method.

Freeze-dried:

Freeze drying involves the removal of water by sublimation through freezing. This is a more expensive process than other methods of drying, but produces a soluble with larger granules for a more favored visual aesthetic.

Agglomerated:

Agglomerated soluble coffee is often described as somewhere between spray-dried and freeze-dried. Produced using the spray drying method, the fine particles are then gathered into larger particles using a re-hydration process. This produces a visually more favorable product, with a slight increase in solubility.