Instant coffee is produced after grinding and extraction by percolation. Instant coffee is prepared in either of the following way:
*By forcing an atomized spray of very strong coffee extract through a jet of hot air. This evaporates the water in the extract and leaves dried coffee particles, which are packaged as instant, or soluble, coffee. Most spray-dried instant coffees have been marketed in a granular form, rather than the small special spray-dried form, since the mid-1960s.
*By freeze-drying, which results in a product that looks somewhat like ground roasted coffee and retains some of coffee’s aroma. Freeze dried coffee has a longer shelf life than spray-dried coffee.
Spray and freeze fried coffee extract have generally lost their original volatile flavor and aroma compounds. The flavor of instant coffee can be enhanced by recovering and returning to the extract or finished dry products some of the natural aroma lost in processing.
The aroma constituents from the grinders, percolation vents and evaporators may be added directly or in concentrated or fractioned form to achieve the desirable product attributes.
Processing of instant coffee
