Instant coffee grains. Coloured scanning electron micrograph of instant coffee grains (granules). Instant coffee is a dried aqueous solution of roasted coffee. The drying process produces hollow particles of low density by either spray-drying or freeze-drying. Both processes avoid nutritional and functional damage and the resulting beverage usually contains 400 grams of coffee per litre. Magnification: x16 at 6x7cm size.