Grain rolling: conditioning is key to quality
Tom Burns, Technical Manager and Jack O’Hare, Business Director
It is estimated that 500,000 tonnes of grain (mainly Barley) is rolled for animal feeding in Ireland each year. As we head into another winter feeding season we feel it is important to restate what the fundamental purpose of rolling is and how to achieve an acceptable rolled grain quality
The main reason for rolling grain is to crack or break the grain kernel in order to allow easier access to the nutrient rich centre of the grain by the microbes in the animal’s digestive system . The level of processing required varies with different animals – small ruminant animals (and poultry) can digest whole grains, larger ruminant animals will pass some amount of whole grains without digesting them and pigs cannot digest whole grains at all.
Rolled grain quality
There are many differing opinions on what “good quality” or “well rolled” Rolled Barley should look like and equally many differing conditions and circumstances giving rise to the variation in end product appearance. Ideally the grain kernel should be cracked, the grain slightly flattened and the fine material retained within the grain kernel. Dust level should be minimised as dust is easily lost to the atmosphere during subsequent handling – loading and tipping – and it is the most valuable part of the grain. The objective is to have a robust rolled grain which can withstand further processing when added to feed.
Grain rolling: conditioning is key to quality
The process of grain conditioning (or tempering) is not a new concept and Adesco have been supporting customers with its Grain Conditioning (GC) Programme since 1997. The process involves the addition of Water + a Surfactant Mould Inhibitor to the grain. Prior to conditioning it is essential to establish the initial moisture content of the grain. This will ensure the correct addition to achieve an agreed target moisture prior to rolling and result in the production of a good quality rolled grain.
Following harvest 2014 where average moisture of grain in store is lower than normal the process of adding conditioned moisture to grain to achieve the correct target moisture pre rolling is most important. Once the target moisture is achieved this will result in the following:
- Good physical quality rolled grain
- Reduced losses
- Good return on investment to boost margin
- Nutritional benefits (further article on the nutritional benefits later)
How to achieve the good quality rolled grain
In October of 2013 during training days with customers some key aspects highlighted were:
1. Grain Size and Moisture of grain
2. Rolling Process and Corrective Action
3. Sampling and Analysis
1. Grain Size and Moisture Content of Grain.
Grain size varies due to variety, growing conditions etc but it is the evenness of grain size as it passes through the roller that impacts on the level of processing each grain receives. Rolling uneven sized grain may result in some smaller grains not being cracked and some larger ones being over crushed. In this situation the throughput of the roller may also have an influence.
The moisture content of the grain also has a major influence on how the finished rolled grain will look; if the grain is dry the kernel will tend to crack and shatter giving rise to high levels of dust.
Adesco carried out a trial in 2011 to demonstrate the difference in rolling dry grain compared to conditioned grain. The following is a summary of Economic Benefits, Process Improvement and Product Quality:
- Substantial Net Yield improvement with Conditioned versus Dry Rolled Barley
- Dry Rolled Barley lost 1% weight in rolling
- Increased roller throughput while reducing energy consumption in rolling with Conditioned Barley compared to Dry Barley
- 84 % less dust particles as compared to dry rolled grain
- Product hygiene preserved as compared to dry rolled grain
2. Rolling Process: Roll condition, Diameter of the rolls, Roll gap, Settings and Throughput
Once the moisture content of the grain has been “standardised” (by conditioning or preserved from harvest) to recommended levels it is then essential to visually assess the rolled grain coming off the roller to establish if the finished quality is satisfactory. This assessment should be done several times during the day. The following are things to look out for and do:
- What level of dust is rising from the pile where the rolled grain is falling? no dust = good quality rolled grain
- Does the material in the centre of the pile look mealy and dusty with coarser material running to the outside?
- What is the overall colour of the pile? Is it grain colour with white flecks?
- Check for the presence of foreign material such as plastic, wood or stone
- Take a sample of the grain and spread it out on a flat surface and check for the presence of whole grains. In general each grain should appear to be cracked and slightly flattened.
It is also important to remember that the temperature of the grain will increase as it passes through the roller and it is essential that the rolled grain is allowed cool down close to ambient temperature before storage in bins or further processing.
Image of roll in good condition
In general there should be no whole grains i.e. un-cracked grains present in the finished rolled product. The presence of whole grains could be due to:
- Worn plates at the side of the rolls allowing grain to bypass the rolls
- High percentage of small grains
- Throughput too high
- Presence of stones or other hard materials
- Roll gap setting too wide or rolls out of tram
- Uneven spread of grain across the width of the roller
Image of worn and damaged parts
It is important to examine the roller, cleaner, magnets and feeder before starting and during the rolling process to ensure there is nothing mechanical affecting the rolled grain quality. If there are a lot of small grains present which are not being rolled properly then adjusting the roll gap setting and reducing throughput slightly may also improve the quality.
If the rolled grain quality is not satisfactory or looks different from previous runs you need to establish the reasons for this. As it is unlikely any significant adjustments have been made to the roller from run to run, the change in appearance will most likely be due to the agreed target moisture not being achieved. In most instances this will be due to variation in initial moisture content therefore constant monitoring of grain moisture content is essential.
3 – 4. Sampling, Analysis and Record Keeping
A sample of all rolling runs and or loads despatched should be kept for at least three months and a small number tested for moisture. This will establish in the mind of the operators the relationship between moisture content and rolled grain quality. Finally it is important to keep records of the rolling process on a daily basis. Not alone is this good practice but also is essential in dealing with complaints (should they arise) in an efficient and professional way.