Wheat DDGS Feed Guide - Western Canadian Feed Innovation ...

SACCHARIFICATION AND FERMENTATION
Today, simultaneous saccharification and fermentation occur in most new ethanol plants. The mash is cooled,
gluco-amylase emzymes are added to break down the liquefied starches into fermentable sugars, and yeast is
added to ferment the sugars. Urea, thin stillage, antibiotics, and a sulfur source may also be added.
“BEER”
The result of fermentation is a slurry “beer” of approximately 12.5% ethanol by volume.
DISTILLATION
The fermented “beer” slurry is pumped continually into a multi-column distillation system where 95% pure ethanol
is removed off the top and whole stillage is removed from the bottom. Whole stillage contains water, fibre, oil,
protein, yeast cells, and unfermented grain particles. Ethanol is dehydrated further to remove all water and produce
anhydrous ethanol.
CENTRIFUGE
The liquid component of whole stillage is removed from the solid components. Thin stillage and wet distillers grains
are produced.
THIN STILLAGE EVAPORATION
Thin stillage can be condensed through evaporation, resulting in a syrup called condensed distillers solubles
(CDS) of approximately 30% dry matter (DM) (Gibb et al., 2008). Relatively large amounts of fat, minerals, water
soluble sugars, proteins and organic acids are contained within CDS.
WET DISTILLERS GRAINS
At this point in processing, ethanol plants may vary in end byproduct type produced: condensed distillers
solubles, wet distillers grains, wet distillers grains with solubles, modified wet distillers grains with solubles, dried
distillers grains, and dried distillers grains with solubles (DDGS). Any byproducts that remain ‘wet’ are limited by
the need for close proximity of livestock to the bioethanol plant. For such a high-moisture feed, storage time is
short because of spoilage and transportation costs are high.
DRyER
Wet distillers grains, condensed distillers solubles, and freshly dried DDGS are combined in a ratio resulting in the
mix entering the dryer at 65% DM and 35-40% CDS (Ileleji and Rosentrater 2008). Rotary drum or ring dryers are
used at varying temperatures and air speeds to dry DDGS.
By the end of processing, one tonne of wheat has produced 375 litres of ethanol and 370 kilograms (37%) of
wheat DDGS (CRFA, 2010) which contains a threefold concentration of protein, fibre and minerals compared to
grain entering the ethanol plant.
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PROCESSING