Soluble Coffee Production

The first instant coffee was invented and patented by the Japanese chemist Satori Kato in Chicago, around the year 1900. Some years later the Englishman George C. Washington, when he was living in Guatemala, invented the first instant coffee that was later produced at commercial scale. Even though the flavor of this coffee was not the best, it had a great reception, particularly amongst the soldiers at the battlefront during the First World War.

To obtain soluble coffee it is necessary to first obtain the beverage through the industrial processes of roasting, grinding and extraction. When this is done the water is removed through a drying processes, and the dry soluble solids shaped either in powder or granulated, are obtained. The rates of extraction vary, in accordance with the species and origins of green coffee used. For example to produce a kilo of soluble coffee one requires a lesser amount of Robusta coffee as raw material than if you would use Arabic coffee. This is why it is relatively exceptional to find in the market, soluble coffee 100% Arabica and even less usual to sell 100% Colombian as it is more costly to produce. Only the most knowledgeable and demanding consumers ask for it.

Another characteristic of the soluble or instant coffee powder or granulated particles remaining after the water has been removed from the coffee extract is its longer shelf life. Unlike roasted coffee, when soluble coffee is packed in a hermetic container it is stable and could maintain its quality during many months or even years, as it is less vulnerable to oxidation processes. It is also very easily prepared as one only has to add water or milk, not needing machines with filters or high pressure.

From the point of view of the industrial process, there are significant differences in soluble coffee elaboration.  One of the most complex steps is to be able to remove the water that is a part of the coffee extract without losing the positive attributes of the final beverage that are lost when applying heat to coffee extracts. As the manner and duration of the processes of application of heat is one the most sensible topics in the production of soluble coffee, different techniques have developed  that have a great effect on the final quality of the beverage.

The concentration consists in reducing the contents of water in the coffee extract, typically from an 85% or 90% up to a 55% or 60% of water. There are various systems to remove the water. The most used in the industry is the evaporation, carried out at vacuum so that the water would evaporate at 45°C (113°F).  In this process special heat interchangers are used. They try to preserve the properties of the coffee heating it in as little time as possible and in a homogenous way.

The Crioconcentration is another method which consists in cooling the extracts using water, at a temperature below 0°C (32°F) The water forms ice crystals but coffee still remains in a liquid state. When the ice crystals are removed through special filters, the remaining extract gets a higher concentration. This method of Crioconcentration extracts is more expensive to produce than others. The extracts receive less heat, thus reducing the risk of loosing certain aromas and flavors. That is why a cup of coffee should not be reheated, as it does not taste the same than a coffee that has just been prepared.

Another aspect, still more crucial to avoid the loss of those highly volatile aromas, is the way the extract is heated toobtain the soluble coffee. There are two ways to eliminate the remaining water in the extracts: the drying through atomization, also known as "spray dried" processes, and the drying through freeze drying process. Even though the two processes are natural, this is to say, they are carried out without any type of additives or material different to the extract, their impact in the quality of the final beverage is very different to the extent that the freeze drying produces a superior quality even though at a higher cost.

 

Drying through atomization

To finish removing the water from the extract a cloud of very small drops is generated; it has a high area of heat transference, which allows evaporating the water through the application of hot air. This task is carried out at temperatures between 40°C and 50°C (104 and 122°F), and at lower pressures. The extract is then atomized in a high tower, and at the moment that it arrives to the bottom, all the water has evaporated and only the powder of soluble coffee remains.

Frequently, the powder of atomized soluble coffee is agglomerated in larger granules moisturizing the powder a little, so that the particles can adhere between them generating granules and a product that dissolves easier in hot water when the final beverage preparation is made.

 

Freeze Drying

Another process to remove the water and to produce soluble coffee is the freeze drying. It consists in freezing the coffee extract at very cold temperatures, in the order of -50°C (-58°F), preventing the loss of aromas and attributes of the beverage that are very valued. When it is subjected to a deep vacuum, of less than a thousandth of the atmospheric pressure, with a marginal addition of heat it is possible that the water remaining in the frozen extract will pass directly from the solid state (ice) to the gaseous state (vapor), a process known as sublimation.

The fact that the product remains at very low temperatures and without contact with the hot air (it is in a vacuum) allows the delicate aromas to remain in the freeze dried coffee particles, thus generating a beverage with excellent characteristics.

Even though the freeze dried process is more costly and complex than the drying through atomization, the consumption of freeze dried soluble coffee has been growing in a constant manner. New coffee consumers demand a coffee of better quality, also when drinking instant coffee. In our  consuming Colombian Coffee link, under our Colombian Coffee section, you will find various ways of consumption and preparation of freeze dried coffee. If you are still more interested in this type of product, please visit Buencafe.com.

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