Instant Coffee Plant

Coffee is a brewed beverage prepared from roasted seeds, commonly called coffee beans, of the coffee plant. Due to its caffeine content, coffee has a stimulating effect in humans. Today, coffee is one of the most popular beverages worldwide. Approximately 90% of world coffee production is represented by the species Coffea arabica; about 9% by the species Coffea robusta; with minor production from the species Coffea libericia. Most processed coffee available in the market are differentiated in terms of Aroma, Blend and Flavour which comes from the way it is processed. Processing coffee to a perfect blend and taste is an art and requires excellent techniques of extraction, roasting, concentration, aroma recovery, spray drying and agglomeration.

SSP has designed and supplied coffee extractors, instant coffee powder plant, aroma recovery system, evaporator, spray dryer and agglomerator to quite a large number of instant coffee manufacturers in India and abroad which are running successfully. With our core competency lying in the field of evaporation and drying technology SSP has collaborated with leading manufacturers of green coffee cleaning, blending, roasting and grinding equipment manufacturer to supply instant coffee plants on turn key basis. SSP has also collaborated with leading companies for supply of continuous freeze drying equipment for production of freeze dried coffee. Coffee produced from SSP's plants have excellent aroma and very good instantibility due to our extensive knowledge and experience on coffee. SSP offers the most energy efficient soluble coffee processing technology and are in a position to supply upto 15TPD instant coffee production plant. Coffee plants with smaller capacities are also available e.g. 50 kg/hr, 100 kg/hr, 150 kg/hr, 200 kg/hr, 250 kg/hr of instant powder production capacities. SSP has already designed, engineered and supplied a few complete plant on turnkey basis & is negotiating a few more.

The first step is thorough cleaning of defective beans, & separation of nails, stones, dirt & dusts. Blending of beans is carried out before roasting by installing volumetric feeders at the outlet of the silos. Through this process various kinds of blends are obtained depending on the taste and demand of the market.

Roasting of coffee beans develops the flavor & aroma which depends on various physical & chemical changes which occur during roasting. Degree of roast & roasting temperature are very important and plays an important role in deciding the flavor and colour of the final product..

The third step is extraction of ground coffee through a continuous process in a pressurized vessel with hot water. To get a better yield seven batteries of counter column extractor cell is used featuring extraction under closely controlled system. Extraction is greatly influenced by factors like type of green coffee beans, degree of roast, type of grind, ratio of coffee to water & mode of heat input.

The extracted coffee solution is passed through a centrifugal clarifier to separate the insoluble solids.

After clarification extracted coffee liquor is passed through the aroma recovery cum evaporation plant. In the plant the volatile aroma is stripped off from the coffee before it enters the evaporator. Based on the boiling points of the aroma constituents SSP has developed a new technology for the extraction of these aroma without diluting them with the water vapours so the result is more pure and concentrated aroma. This technology is called the ARC System which stands for AROMA RECOVERY CUM CONCENTRATION SYSTEM which is integrated with the evaporation system. In the evaporator concentration of the extract is done through multi-effect evaporators with TVR systems for concentration upto 50-55%. It is possible to concentrate the extract further upto 65-70%, to reduce the load on freeze drying system.

The next step is concentration of the extract through multi-effect evaporators with TVR systems upto 50% concentration is achieved.

The concentrated coffee is then converted to instant coffee powder by spray drying. Drying is done under controlled conditions to protect and preserve aroma and flavor in the coffee.

Lastly, the Spray dried powder can be converted into soluble (instant) granules in an agglomerator tower by Re-wet agglomeration technique. This technique results in the formation of bigger sized porus particles, and reduces the bulk density thereby increasing the instantability of the powder. Hence when a spoon of this agglomerated powder is put in water, it disperses completely due to the osmotic pressure of the liquid.

The instant coffee powder is then taken to the tote-bins for storage & packing. For filling into tins or jars, vacuum operated filling system is used. For filling into sachets, a form fill-sealing machine is used. The filled containers/flexible packing are packed in the shipping cartons and sent for dispatch to the finished goods warehouse.

Instant coffee powder is usually made by evaporation of coffee extract upto 40-45% concentration by use of an evaporator followed by spray drying at a high temperature (180-220 °C ). This results in change in appearance, colour, loss of aroma and taste.

However, use of freeze dryer retains aroma, improves appearance and taste because freeze drying takes place at a low temperature which minimizes heat damage and retains volatile components (aroma). It also increases the shelf life of the dried product as compared to standard drying practices.

Freeze-drying involves dehydration of food products at low temperature and pressure. As a result only the moisture is removed, leaving the molecular structure intact. The end product is light in weight with least or no change in volume. Worldwide freeze-drying technology is considered as the ultimate amongst all other dehydration methods. Hence this technique is currently being used for the production of instant coffee.

In a freeze drying system, concentrated coffee (42-45%), is first freezed and then exposed to a low partial pressure (4.6 mmHg) of water vapour when ice sublimes directly to vapour leaving behind dried coffee.

Freeze drying is an expensive process in terms of capital, expenditure and operating cost but results in excellent product quality.

Pre-freezing coffee concentrate up to -5 / -10 °C followed by foaming.
Freezing of the prefreezed coffee liquor at -50 °C in a blast freezer.
Sizing of the freezed coffee particles to a granular size of 3X3mm.
Sublimation of the ice in a vacuum freeze dryer (VFD) under vacuum (0.5 torr) and controlled temperature.

SSP has developed this technology successfully in their R&D laboratory, where a pilot plant has been set up for demonstration.

This extraction system has been designed to increase the total yield of coffee from 48-50% to about 70-75% by hydrolysing spent coffee so that it can attain soluble state without the addition of any acid catalyst. In this process the spent coffee after the extraction process is mixed with a measured quantity of water and fed into the tubular reactor where it is subjected to a very high pressure and high temperature for a pre-determined time period. This leads to hydrolysation and breakdown of the molecules to simpler and dissolvable forms. When liquid at high pressure and temperature leaves through the orifice fitted at the extractor end, hydrolysis is terminated immediately due to sudden drop in pressure which further leads to expansion and evaporative cooling. Further cooling is controlled in a flash tank. The end product contains about 20-30% soluble coffee which is then mixed with the extracted coffee, thus increasing the total yield.