Instant coffee comes in three different forms,
freeze dried, spray dried and liquid concentrate. Although the
initial brewing process is the same for all methods they vary
greatly with the methods used to produce the final coffee
product.
Typically the coffee beans chosen for instant coffee production
are from the lower end of the quality scale, since many of the
subtle flavours and aromas of the more expensive types are lost in
the production process.
We discussed freeze dried coffee in different article and here we
look into the production of spray dried coffee.
Stage One - This stage involves the production of
large quantities of freshly brewed coffee using industrial bulk
brewers. Freshly ground coffee is put into contact with hot water
in industrial brewers until the desired degree of extraction has
occurred. The process can either be the drip filter method that
many use in the home or an industrial version of the coffee
percolator. Much waste product is produced in the initial brewing
chambers in the form of used coffee grounds. However these days
they are recycled for use in animal foods, used as organic fuels or
processed as compost.
Stage Two - The resulting coffee liquor liquid is
then concentrated through an evaporation process where some of the
volatile aroma components are removed and stored to be returned
later prior to packing. This stage produces a thick more viscous
coffee liquid that is then ready for the next stage in the making
of spray dried instant coffee.
Stage Three - The concentrated liquid coffee is
then sent to the spray- drying tower where it is turned into
powder. This is achieved by pumping the coffee concentrate through
an atomizer where it is broken into small droplets. These droplets
react with the hot drying gases in the tower and lose moisture
rapidly. They are are suspended in the drying air and typically
separated by centrifugal action.
The powdered coffee produced can however often be too fine to be
easily used. Consequently it often undergoes an additional process
called agglomeration, which results in a more useable and appealing
product. The fine coffee particles are gathered into larger
particles using a partial re-hydration process which produces a
more visually tempting finished product somewhere between the
consistency of powder and freeze dried coffee.
Spray dried coffee is considerably cheaper to produce that freeze
dried coffee, the latter of which is considered the higher quality
product.
Written by Fenton Wayne - (Fenton Wayne is an independent
advisor in the coffee and vending trade where he has over 25
years experience. This article has been submitted to and
distributed by www.submityourarticle.com)