Aroma Recovery in Soluble Coffee Process

Much of the soluble coffee in the world today contains only a small fraction of the flavour present in the roasted bean. It is well known within the coffee industry that flavour losses occur at every stage of the soluble coffee production process. The majority of this flavour is lost in the extraction, evaporation and drying steps. Many of Flavourtech’s existing customers report that prior to using the Spinning Cone Column up to 90% of their flavour was lost between roasting of the coffee bean and consumption of the soluble product.

Today, the use of the Spinning Cone Column (SCC) is a standard piece of equipment in soluble coffee plants as it can dramatically increase the amount of coffee flavour and aroma in the final cup of coffee. There are over 60 installations of the SCC around the world in countries that include: South America, United Kingdom, Germany, Russia, Japan, Indonesia, Australia, Vietnam, Malaysia, China, USA, Korea and New Zealand.

The SCC can be used in several different ways and in different plant configurations to achieve a manufacturer’s specific objectives. Flavourtech not only works closely with its clients to optimize SCC integration into their process, but also offers its extensive experience in helping improve process efficiency before and after the Spinning Cone Column unit.

Two processing options are available to soluble coffee companies that are interested in using the Spinning Cone Column for the capture and management of their coffee aroma. These are:

1. Essence recovery from a liquid extract – this is the preferred choice by high-volume processors.

The Spinning Cone Column is normally incorporated into a traditional soluble coffee plant by taking the liquor after extraction and collecting the volatile compounds (flavour/aroma) before the stripped liquor undergoes concentration. The flavour essence is stored under optimum conditions and avoids thermal exposure and inherent loss or damage normally experienced during concentration. The flavour is then returned to the concentrated extract immediately prior to spray drying or freeze drying.

A further advantage of the SCC in this situation is its ability to broadly fractionate the volatile compounds recovered. Most soluble coffee processors accept that the high temperature and pressures generated in the percolation cells produce an extract with some heavy, "nicotine" type notes. These flavours are undesirable in the final soluble coffee and can be removed and discarded by the SCC without loss of the desirable light, "buttery", "woody" characters.

The diagram below illustrates the positioning of the SCC in a typical soluble coffee process.

2. Essence recovery from slurry - which facilitates capture of even more intense coffee essence (as may be sought for possible use in other products).

The SCC can process feed streams with high proportions of suspended solids. If a slurry of roast and ground coffee beans and cold water is fed into the SCC, it is possible to capture all of the coffee aroma, including top-notes, reminiscent of a fresh brew. It is therefore possible to collect an intense, fresh-roasted, coffee character by literally brewing the coffee in the Spinning Cone Column itself. The presence of the coffee solids greatly enhances the recovery, in terms of both quality and quantity, of volatile compounds.

Using the SCC to process a coffee ground slurry allows the extraction of the desirable coffee flavours in far greater quantities than when a liquid extract is processed, as shown by the GC analysis below. The essence recovered from slurry is not only more concentrated, but also generously weighted in distinctive front-end compounds that many soluble coffees lack. Reincorporation can occur via addition to the concentrated dryer feed stream.

The key to the success of this step is the intelligent integration of SCC slurry processing within the confines of the traditional coffee process. Flavour extraction is completely separate from hydrolysis and soluble-solids extraction, thus allowing each process to be optimised independently. This then allows each separate part to be fine tuned with respect to the two variables of prime importance to soluble coffee manufacturers: Yield and Flavour.

Flavour houses around the globe process coffee slurries in the SCC to produce the world's finest coffee flavours.

Click here to find out more about Flavourtech’s Spinning Cone Column technology.