Instant coffee has a lot of applications. Instant coffee can be dissolved into water, milk or chocolate milk. It is also used in desserts.
|Extraction and filtering|
According to the food law it is not allowed that the instant coffee has any additions. The quality of instant coffee is improved by recent developped drying methods.
Extraction and filteringThe production process of instant coffee is similar to the production of 'traditional' coffee. After the grinding step an extract of the coffee is made from the coffee aromas. The extract is made by adding hot water to the ground coffee. Result is a very strong coffee.
Next the extract with the ground coffee is filtered. The ground coffee remains in the filter
boiling temperature and water evaporates. Evaporation is mostly done in vacuum to lower the boiling temperature. This gives less product damage. A part of the aromas evaporates with the water. This is the main disadvantage of the evaporation method.
temperature of 0-20ºC and a water activity of 0,98) are dispersed in a tower into a stream of hot air. At the top of the tower hot, dry air, with a temperature of 150-250ºC, is blown.
The extract gets a temperature of 50ºC immediately and releases its moisture to the hot air. Down in the tower the relative wet air a temperature of 90ºC and humidity of 14% and the dry coffee powder has a temperature of 70ºC and water activity of 0,35. The falling time of a drop of extract is 10 to 30 seconds. Under in the tower the drops are separated from the wet air with help of a cyclone.
The product made is a fine powder. This powder clots and dissolves badly. Granulated powder is more soluble. To make granules from the powder, the powder has to be agglomerated with water vapour. The powder clots slightly and controlled granules arise.
After centrifuging the product is put in a full vacuum and radiated. The remaining ice crystals transforms into vapour without defrosting. This process is called sublimation. Advantage of sublimation is that the structure of the product remains unchanged. At first only the ice crystals at the outside of the product sublimates. Later the water is removed from the centre of the product as well.
The quality of freeze dried products is very high, mainly because of the low temperature during the process. The aromas stay preserved and there is no change of colour. Nowadays the instant coffee is freeze dried mainly.
Instant coffee needs to be packed without oxygen and moisture. Most used packaging for instant coffee is glass. Correctly packed instant coffee has a shelf life of 18 months.