Ferguson Impingement system

Coffee is a beverage, served hot or with ice, prepared from the roasted seeds of the coffee plant. These seeds are almost always called coffee beans. Coffee is the second most commonly traded commodity in the world.

History

Coffee has its history back as far as the 9th century CE. It was said to originate from Ethiopia and spread to the rest of the world via Egypt and Europe. Over the ages, coffee has met both resistance and acceptance by many.

The word “coffee” is derived from the Arabic word “Kahweh”, which originally meant wine or other intoxicating liquors.

Instant Coffee is a beverage derived from brewed coffee beans. Through various manufacturing processes the coffee is dehydrated into the form of powder or granules. These can be rehydrated using hot water to provide a drink similar to brewed coffee.

The advantages of instant coffee are speed of preparation and long shelf life (natural coffee, especially in ground form, loses flavour as its essential oils evaporate over time).

Production

Below are general outlines for stages in modern production of instant coffee:

Roasting

The green coffee bean itself has no desirable taste; it must first be roasted to bring out flavour and aroma. The process for this is the same for regular coffee as it is for instant coffee.

Grinding

The next step reduces the beans to a size of anything between 0.5 and 1.1 mm in order to allow the coffee to be put in solution with water for the drying stage.

Extraction

Once roasted and ground, the coffee must be put into solution with water. This stage is called extraction.

Freeze Drying

The basic principle of freeze frying in the process for producing instant coffee is the removal of water by sublimation.

Since the mass production of instant coffee began in post-WWII America, freeze drying has grown in popularity to become a very common method. This is often because although it is frequently more expensive than other methods of drying it generally results in a higher quality product.

The Freeze Drying Process:

	Agglomerated wet coffee granules are frozen. For instant coffee this is a very important stage. Freezing too fast leads to large ice crystals and a very porous product and can also affect the colour of the coffee granules.
	Frozen coffee is placed in the drying chamber, often on metal trays.
	A vacuum is created within the chamber. The strength of the vacuum is critical in the speed of the drying and therefore the quality of the product. Care must be taken to produce a vacuum of suitable strength.
	The drying chamber is warmed, most commonly by radiation but conduction is used some plants and convection has been proposed in some small pilot plants. A possible problem with convection is uneven drying rates within the chamber, which would give an inferior product.
	Condensation – the previously frozen water in the coffee granules expands to 10” its volume, the removal of this water vapour from the chamber is vitally important, making the condenser the most critical and expensive components in a freeze drying plant.
	The freeze dried granules are removed from the chamber and packaged.

BMA Nederland B.V.-Ferguson  has a lot of know-how of stage 1 ‘Freezing of the coffee’.

The coffee will be frozen on a stainless steel freezing belt. The liquid coffee will be injected on the belt with a thickness of appr. 10 mm and will be frozen till a very low temperature.

To prevent discoloration of the product freezing will be performed exactly conform a temperature curve. This will be possible with the Ferguson  Impingement System.

Underneath and above the product, impingement boxes have been placed to make this possible.

Advantages of our system are:

	Short process times
	Low energy consumption
	Homogeneous cooling of products
	Easy access for cleaning purposes
	Loss of moisture is lower than with any other freezing method

Our systems are also suitable for a lot of other products, click here.