Do you know that the famous classical music composer and pianist Ludwig van Beethoven insisted on drinking a cup of coffee made from exactly 60 pieces of coffee beans? Currently, around 50% of the world’s green coffee beans undergo processing through instant coffee manufacturing equipment to produce instant coffee. The process requires roasting, grinding, brewing, and heating to obtain the extract; the coffee extract will either go through a spray drying process or a freeze-drying process.
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Let’s start: roast and grind your coffee beans…
The instant coffee production process starts with cleaning and sieving the green coffee beans to remove dirt and unwanted debris. Then, they are loaded up in large ovens for roasting at a temperature of 200°C while being constantly stirred to ensure even roasting without burning. The roasting step takes only 10 minutes – just the time for the beans to turn brown. Before grinding them into powder using an industrial grinder, they are cooled rapidly down to 40 °C. While grinding the beans, a large amount of their aroma is released into the air.
… then brew powder, and condense extracts using instant coffee manufacturing equipment
To minimize the loss, nitrogen gas is pumped through the ground coffee to collect the aromas and store them in a tank. The aroma will be added later in the production. The coffee powder goes to the pressure vessel, where water and steam are applied to make brewed coffee. Then, the brewed coffee is heated in the evaporator at 70 °C until it is condensed by 50% into an extract. This extract will undergo either a spray drying or freeze-drying process to obtain instant coffee. Both methods remove moisture and turn our coffee extract into instant coffee.
Instant coffee production: the freeze-drying method
Freeze-drying is the most common process used to remove moisture from coffee extracts. This process minimizes the chances of altering the flavor and aroma. The process involves freezing the coffee extracts to turn them into solid slabs. We are talking about ice age temperatures, around -40 °C or lower. The slabs are broken down into granules and loaded into trays for vacuum heating. The process removes the remaining moisture from the granules by applying heat at 60 °C under pressure in a strong vacuum.
This is called the sublimation process, where solid crystals turn to vapor without passing through a liquid phase. The aromas collected and stored in the tank are sprayed over the granules as they pass through giant sacks before they are prepared for packaging.
Instant coffee production: The spray-drying method
Another method used for drying coffee extract is the spray-drying process. The process involves atomizing or spraying the liquid coffee extract into tiny droplets. At the same time, a high-velocity stream of hot air at more than 500 °C quickly vaporizes the moisture leaving instant coffee powder.
This method can quickly dry the coffee extract into powder but may lose part of its flavor and aroma due to high temperature and pressure during the drying process. In terms of operating cost, this method is cheaper to operate compared to the freeze-drying method.
Producing energy from byproducts of instant coffee
Producers utilize most of the byproducts to minimize waste. For instant coffee producers, the main byproduct is spent coffee grounds which can be a versatile source of green energy. The coffee grounds can produce the same amount of energy as coal when burned. Spent coffee grounds can also be processed to extract more oil to be used as biodiesel, while the byproduct after oil extraction can be used as fertilizer or formed into briquettes or pellets to be burned into boilers as biofuel. Making coffee waste into usable energy is much more sustainable and environment-friendly for producers.