Progress on the Spray Drying of
Distillers' Solubles
J. W. Ridgway, W. V. Baldyge, and M. Scarba
Joseph E. Seagram & Sons, Inc.
Louisville, Kentucky
Pre-History
A source of considerable waste under older methods of grain distillery operation was the disposal of fermented mash residue (stillage)
after alcohol removal by distillation. This material was frequently run
into streams or field troughs from which cattle or swine were fed.
Either procedure resulted in considerable pollution and waste. In some
cases, small monetary returns were obtained from the sale of the whole
stillage in barrels or small tanks.
With the passage of stringent anti-pollution laws and the realization that a profitable feed by-product could be obtained from this material, progressive distillers began to introduce processing equipment for
the by-product feed recovery. At first, the whole stillage (about 7%
solids) was screened and pressed, and the presscake was dried in rotary
steam tube driers to be sold as distillers' light dried grains. The screen
and press liquor (thin stillage) was then either run to waste or sold
very cheaply in barrels or small tanks. However, this thin stillage
containing 3.5 to 5.0% solids could also be processed profitably. Most
modern distillers concentrate this material by multiple-effect evaporation to a syrup containing 25 to 40% solids.
In the earlier systems of modern by-product feed recovery, this
syrup concentrate was mixed in with the presscake to be dried with it
in rotary driers and sold as distillers' dark dried grains with a higher
price value than distillers' light dried grains. However, it was soon discovered that this evaporator syrup contained elements in it which made
it superior to either distillers' light or dark dried grains for certain
types of animal feeding. As the result, the most progressive modern
distilleries process this material separately as distillers' dried solubles,
which command the highest price.
The Seagram organization has pioneered extensively in the commercial development of by-product feed-recovery methods. The first process
developed and utilized steam drum driers for dehydrating the evaporator syrup. The material comes off the drum in thin sheets, which are
then flaked. The most recent advancement in the processing of distillers'
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