How Laboratory Data Improves Pellet Quality, PDI and Energy Efficiency
Quality control should not be the last step of feed production. It should be the first production control tool. When laboratory results on moisture, particle size, mixing and conditioning are used to adjust the process in real time, feed mills can achieve higher pellet durability, fewer fines and lower specific energy consumption.
This was the central message of the presentation “The New Generation of Quality Control in Pellet Milling”, delivered by Bastak Instruments CEO Zeki Demirtaşoğlu at the IAOM MEA Regional Feed Milling Forum 2026 on 23 September 2026. This article summarises the approach, the literature-based simulation behind it, and what it means for poultry and cattle feed producers.
Why pellet quality is decided long before the pellet press
Pellet quality is often attributed to the pellet mill and its die. In practice, it is the result of the whole process: raw material characteristics, grinding, mixing, conditioning and pelleting conditions together determine the final pellet. Variations at any of these stages show up as changes in Pellet Durability Index (PDI), fines generation, specific energy consumption and process stability.
The economic stakes are high. Modern feed mills typically operate at 20–60 tonnes per hour, the pelleting process alone accounts for roughly 25–40% of a mill’s electrical energy consumption, and feed represents about 60–70% of total livestock production costs. In a 30 t/h mill, around 30 tonnes of raw material become finished pellets every hour, so even small variations in incoming material can create substantial losses before the product reaches the customer.
The problem with end-of-line quality control
In many feed mills, quality control is still a verification activity performed after production is complete. Laboratory results are recorded for documentation but are rarely fed back into production management. By the time a low PDI or high fines value is reported, the batch has already been produced, the energy has already been consumed and the corrective action comes too late.
The laboratory should evolve from a quality verification unit into a real-time process control center that continuously supports production decision-making.
Five control points where laboratory data should drive production decisions
1. Raw material moisture
Moisture is one of the key parameters affecting conditioning, storage stability and pellet quality. In a conventional approach, steam addition stays constant and batch-to-batch variations are ignored. In a process-driven approach, rapid moisture analysis is carried out on every incoming batch and steam and water addition are adjusted accordingly.
2. Particle size distribution (PSD)
Particle size directly affects pellet durability, energy consumption and animal performance. Instead of setting the hammer mill only by capacity or motor load, screen size and grinding parameters are optimised using sieve analysis results. The outcome is a more uniform pellet structure, lower energy consumption and more stable PDI.
3. Mixer uniformity (CV test)
Uniform mixing is essential for nutrient consistency and process stability. Rather than using a fixed mixing time, mixing time and mixer loading are optimised according to coefficient of variation (CV) results. When PDI drops, mixer performance is investigated alongside pellet press settings.
4. Conditioning
Correct conditioning improves starch gelatinisation and pellet durability. Steam and temperature are often set by operator experience. In the next-generation model, moisture, temperature and retention time are continuously optimised using laboratory feedback.
5. Pellet press energy, PDI and fines
Specific energy consumption (kWh/t), PDI and fines are evaluated together with moisture, PSD and conditioning data. When PDI decreases, the entire process is reviewed in sequence (moisture, then PSD, then conditioning, then the press) instead of only changing the die.
Simulation results: what a 30 t/h feed mill can gain
To show how laboratory data can be converted into production decisions, a literature-based industrial scenario was modelled for a feed mill operating at 30 t/h (720 t/day). The model compares a conventional approach with process-driven quality control.
KPI | Conventional | Process-driven QC | Illustrative impact (720 t/day) |
Specific energy consumption | 18 kWh/t | 16 kWh/t | 1,440 kWh/day saved |
Pellet Durability Index (PDI) | 89 | 93 | +4 points |
Pellet fines | 7.0% | 4.0% | ≈43% reduction |
Daily pellet fines | 50.4 t/day | 28.8 t/day | 21.6 t/day less |
Note: These figures come from a literature-based simulation of a representative 30 t/h feed mill. Actual results depend on raw material quality, equipment and process conditions.
Key feed quality parameters to monitor
Physical and nutritional parameters should not be evaluated in isolation. Together they determine nutritional value, physical quality, processability and overall feed performance. Typical ranges presented at the forum include:
Parameter | Typical range | Risk if out of range |
Moisture | 10–12% | Too high promotes mould; too low reduces pellet binding |
Pellet Durability Index (PDI) | >85% | Dusty feed, wastage and feed sorting |
Bulk density | 600–750 g/L | May indicate poor compaction or excessive fines |
Crude protein | 12–23% (species dependent) | Growth retardation or unnecessary feed cost |
Crude fibre | 5–15% ruminant / <5% monogastric | Impaired digestion or lower digestibility |
Ash | 4–8% | Mineral deficiency or contamination and formulation errors |
In the laboratory, these values can be determined with Kjeldahl protein analysers, a fibre extractor for crude fibre, an oil determination device for crude fat and a muffle furnace for ash, while NIR provides rapid screening between reference analyses. For how the two approaches compare, see NIR vs laboratory testing of grain.
From verification to decision support: Laboratory → Data → Decision → Process → Performance
The competitive advantage of future feed mills will not be defined only by more advanced pellet presses or higher capacity. It will be defined by the ability to turn laboratory data into timely, accurate production decisions. Integrating rapid analysis, automation and standardisation makes the laboratory the central driver of process optimisation, operational efficiency and sustainable pellet production.
How Bastak Instruments supports process-driven quality control
Bastak Instruments manufactures laboratory equipment for grain, flour and feed analysis, used in more than 50 countries. The following instruments cover the control points described above:
- Rapid composition analysis (moisture, protein, fat, fibre) with the DA 9000 NIR analyser
- Incoming raw material moisture with the Moisture Meter 16000
- Particle size distribution with the Sieve Shaker 8000 and ISO sieve sets
- Representative sample preparation with the Hammer Mill 1900
- Pellet durability (PDI) and fines testing with the Pellet Tester 17000
Frequently Asked Questions
What is the key indicator of pellet physical durability?
The Pellet Durability Index (PDI). It measures how well pellets resist breakage during handling, transport and storage. A PDI above 85% is a commonly used target.
What is a typical moisture range for finished feed pellets?
Around 10–12%. Higher moisture increases the risk of mould, while lower moisture reduces pellet binding.
Why measure moisture on every incoming batch?
Because moisture determines how much steam and water should be added during conditioning. Batch-based moisture data lets the mill adjust conditioning instead of using fixed settings.
Does a low PDI always mean the die needs changing?
No. Low PDI can originate from moisture, particle size, mixing or conditioning. Process-driven quality control reviews these stages in order before changing the die.
Related reading
- Bastak Pellet Durability Index (PDI) tester
- NIR vs laboratory testing of grain
- Mycotoxins and moisture control in raw materials
- All feed quality control devices
Want to turn your feed laboratory into a production decision center? Contact Bastak Instruments at export@bastak.com or info@bastak.com to discuss the right instruments for your mill.
