Distillers Dried Grains with Solubles

Brief Overview

Distillers Dried Grains with Solubles (DDGS) is the most common coproduct from many ethanol plants. It is typically dried to about 10% moisture content, to ensure a long shelf life and to reduce flowability issues during storage and transport. It can be transported by truck, rail, and boat to local livestock producers, throughout the country, or even to overseas markets. DDGS has increasingly been exported to globally in recent years.

Manufacturing Process

DDGS is by-product of ethanol manufacturing process. The ground grains are mixed with water and enzymes to produce dextrose, this process is called saccharification.  After saccharification, yeast is added to start the fermentation process, which produces alcohol and CO₂. The alcohol passes through a continuous distillation process to yield ethanol and the by-product called whole stillage is separated using centrifuge. The supernatan that has been dried is called DDGS.

Animal feed is the most important use for ethanol coproducts (more than 99%, in fact). Coproducts contain nutrient profiles that parallel the grain that was used for fermentation (most of the starch is used by the microbes, so the remaining nutrients are concentrated by approximately 3x), and they are highly digestible. It has been shown that DDGS can replace corn in livestock diets on a 1:1 up to a 1.2:1 level, depending on the species.

The majority of distillers grains are used in beef and dairy feeds, because ruminants can easily utilize high levels of fibre. But, monogastrics (including swine, poultry, fish, and others) have been shown to readily digest DDGS as well, and these markets continue to gain importance. Many feeding trials have been conducted on coproducts over the years, for both monogastrics and ruminants, in order to increase and optimize coproduct use.