As the instant coffee segment continues its trend toward diversification, premiumization is on the rise, with more and more specialty instant products emerging. Australian technology company Flavourtech is helping by providing a means to produce higher quality specialty instant coffee on a commercial scale.
The company’s processing technologies revolve around capturing natural flavours through a gentle, yet efficient, process, and their Rotating Disc Column (RDC) is perfect for today’s instant coffee companies.
The RDC is a continuous extraction device operating closely to plug flow — an idealised flow without any mixing in the axial direction but perfectly in the radial direction. Its function is to hold a slurry flow of solids in liquid for a specified residence time and at a specified temperature so that the transfer of soluble components from the solid particles to the liquid extract is maximised.
Within the RDC is a central, vertical drive shaft. Attached to the shaft is a series of rotating baffles, and between each adjacent pair of rotating baffles is a stationary baffle. Slurries are pushed from the bottom of the RDC up through the column, ensuring identical extraction time and consistency.
The RDC can be used on its own or inserted into Flavourtech’s Integrated Extraction System (IES). The IES is a continuous, automated processing line that allows customers to produce aromas, extracts, and concentrates for both soluble and ready to drink coffee and tea products.
In the case of instant coffee, the RDC allows a continuous flow of coffee slurry for high temperature extraction. The slurry is exposed to temperatures of between 150° to 195°C for just 20 minutes enabling further hydrolysis to take place. The end result is a premium product in terms of quality and aroma compared to one produced with traditional techniques, where extraction cells are set at much higher temperatures for 3 to 4 hours, instead of 20 minutes.
The RDC allows temperature, pressure, and residence times to be precisely controlled to obtain near identical conditions for all parts of the mixture being processed. Its unique design ensures the materials flowing through it are maintained in a dynamic state, preventing settling and the formation of static pockets. The risk of burning and the formation of undesirable flavours is also greatly reduced due to the precise temperature control and reduced residence times.
The internal volume of an RDC is determined by the desired product flow rate and holding time and is tailored to customer requirements. It is often noted by Flavourtech customers that the factory footprint of an RDC is quite small compared to traditional coffee extraction where multiple tanks/cells are used.
With more than 40 years of experience in the flavour industry, Flavourtech understands that the best natural aroma comes from processing raw materials before they are subjected to high temperatures.
The company has therefore designed soluble solids extraction through the RDC to take place after the aroma recovery step using its popular Spinning Cone Column (SCC) technology. In contrast, in traditional instant coffee processing, aroma recovery takes place after high temperature extraction — by which point many of the desirable flavours have already been lost.
Within Flavourtech’s IES, a coffee slurry is first processed through the SCC to capture fresh roast and ground coffee notes. This aroma is then protected while the rest of the slurry is sent to the RDC for extraction of soluble solids. Insoluble solids are then removed, and the resulting extract is gently concentrated with Flavourtech’s Centritherm® evaporator prior to aroma add-back and spray drying or freeze drying. This means that the roasted coffee aroma is protected from high temperature processing. The resulting instant coffee smells and tastes like freshly brewed.
In summary, the IES process is continuous, automated and allows manufacturers to produce a consistent, high quality soluble coffee, day in and day out, with minimal fuss and labor. For more information: www.flavourtech.com