Ever wondered how instant coffee is made?
Instant Coffee is actually just brewed coffee that has had it’s water content removed by a drying process. There are two methods for producing instant coffee. Both are fairly straightforward processes involving the use of coffee concentrates, but interestingly they apply extreme opposites in temperature to the coffee concentrate to achieve the same end product of water soluble instant coffee. Freeze drying uses freezing as the name implies and spray drying involves spraying coffee through very hot air.
Freeze Dried Instant Coffee
Freeze dried instant coffee is usually more expensive than spray dried instant coffee. The process generally retains more coffee flavor and involves a more complex process. Brewed coffee is left to sit in order for the water evaporate which results in a coffee concentrate. This concentrate is then frozen to around -40 Fahrenheit (-40 Celsius, not a typo it’s the same at this temperature). The remaining water freezes into ice crystals. Sublimation , a process where the ice is converted from solid to vapor without going through the liquid state, is used to remove the ice. What’s left is dry grains of coffee which can be reconstituted in water.
Spray Dried Instant Coffee
In spray drying, the water is also evaporated from brewed coffee to form a concentrate. The coffee concentrate is then sprayed into the top a large chamber through very hot, dry air. As the coffee droplets fall through the hot, dry air, the remaining water evaporates leaving a dry coffee powder by the time they land. More flavor is lost through this method than freeze drying due to the effects of the high temperatures which strip some of the oils and aromas from the coffee in this method.
There has been considerable research and effort put into producing instant coffee that smells and tastes like brewed coffee. You can read about the history of instant coffee in an upcoming post.