How to Make Pellets from Hay and Straw Using an Advanced Pellet Machine

Globally, agricultural residues — including straw and hay — represent over 5 billion tons of available biomass annually (FAO, 2022). In Europe alone, straw generation exceeds 130 million tons per year, yet only a fraction is currently converted into high-value pellet products.

Turning hay and straw into pellets is one of the most cost-effective ways to monetise agricultural residues on the farm. Instead of handling bulky, difficult-to-store loose material, pelletizing converts it into compact, dense, easy-to-manage output — for use as animal feed, biomass energy, or premium bedding.

With an advanced hay pellet machine, the process becomes consistent and scalable — suitable for both small farm operations and semi-industrial biomass production.

Benefits of Converting Hay and Straw into Pellets — Why It Makes Economic Sense

Loose hay and straw present multiple logistical and commercial challenges: they are bulky (bulk density ~50–80 kg/m³), prone to moisture damage, and difficult to transport economically. Pelletizing solves all three:

Metric	Loose Straw vs. Straw Pellets
Bulk density	50–80 kg/m³  →  550–700 kg/m³
Storage space required	~10× more for loose material
Transport cost per ton	~3–5× higher for loose straw
Calorific value (net)	~14.5 MJ/kg  →  ~16–17 MJ/kg (pellets)
Shelf life	Weeks (damp risk)  →  12+ months (sealed)

 Key advantages of pelletizing:

• Reduces storage space by up to 8–10× — converting loose material into dense pellets

• Improves transportation efficiency — higher value per truck load

• Converts agricultural residue into animal feed, biomass energy, or premium bedding pellets

• Eliminates dust and reduces fire risk compared to loose straw

• Creates a marketable, standardised product with EN 17225 or equivalent quality certification

Raw Material Preparation for Pellet Making

1. Feedstock Preparation and Material Quality

Proper preparation is the single most important factor in pellet quality. Poorly prepared hay or straw — whether contaminated, over-dried, or too coarsely cut — will result in weak pellets, die blockages, or high energy consumption.

Before pelleting, ensure:

•  Material is free from stones, metal, and large debris — use a magnetic separator

•  No excessive bark or thick woody stems in the mix

•  Uniform batch composition — mixing species or harvest years can alter binding behaviour

2. Moisture Control for High-Quality Pellets — The Critical Parameter

Moisture content is the single most controllable factor affecting pellet quality. For hay and straw pelleting, the ideal moisture range is 12–15%.

Moisture Level	Effect on Pelleting
< 8%	Poor binding, crumbly pellets, high energy consumption
8–11%	Acceptable but suboptimal — risk of excessive fines
12–15%	Optimal — smooth die passage, dense pellets, good durability
16–19%	Risk of steam and blockage — add conditioning step
> 19%	Machine blockage, pellet surface cracks, mould risk in storage

Pellet Making Process: Step-by-Step with a Pellet Machine

Step 1: Size Reduction — Grinding to the Right Particle Size

Hay and straw must be reduced to a particle size of 3–8 mm before entering the pellet machine. This is typically done with a hammer mill or knife mill.

• Target particle size: 3–6 mm for optimal die passage in a straw pellet mill

• Too coarse (>10 mm): poor pellet formation, excessive resistance in the die

• Too fine (<2 mm): excessive fines, dusty output, increased energy per ton

The grinding stage also improves material homogeneity — critical when mixing hay and straw species.

Step 2: Pelletizing with the Hay Pellet Machine

The prepared material is fed into the pellet mill ring die or flat die at a controlled, consistent rate. Inside the pelletizing chamber, rollers compress the material through the die holes at pressures of 500–2,000 bar.

For straw and hay, typical operating parameters:

• Die hole diameter: 6–10 mm for energy pellets; 4–6 mm for animal feed

• Compression ratio: 1:5 to 1:8 for agricultural fibre materials

• Pelletizing temperature: 80–120°C (generated by friction — no external heat needed for straw)

Step 3: Cooling and Final Output

Freshly produced pellets exit the die at 80–120°C and contain 1–2% more moisture than the input material. They must be cooled before storage:

• Counter-flow cooler: preferred method — cools pellets from 80–120°C to ambient +5°C

• Cooling time: typically 5–15 minutes depending on pellet diameter and air volume

• After cooling, pellets reach final moisture of 8–12% and durability of 95%+ (EN 15210)

Applications of Hay and Straw Pellets — Commercial Markets

Pellets made from hay and straw serve multiple growing markets:

• Animal feed for horses, ruminants, and rabbits — premium hay pellets retail at €350–600/ton

• Biomass energy — industrial heating plants buy straw pellets at €120–180/ton (EN 17225-3)

• Equine and small animal bedding — growing premium segment, €200–350/ton

• Cat litter pellets — highest margin application, €400–800+/ton retail

• Biochar and activated carbon feedstock — emerging market, significant premium

This breadth of applications reduces commercial risk and allows producers to switch markets based on pricing.

Improving Efficiency with the Right Pellet Machine: Matching Machine to Material

Straw and hay present higher fiber content and lower natural binding agents compared to wood. The right machine selection is therefore critical:

• Ring-die pellet mills: preferred for continuous commercial production above 500 kg/h

• Flat-die pellet mills: suitable for small batches, farm-scale testing, and mixed materials

• Bonfiglioli or equivalent direct-drive gearboxes: reduce mechanical losses vs. belt drive

Frequently Asked Questions — Hay & Straw Pellets

❓ Can you make pellets directly from straw bales?

✔ Yes, but straw bales must first be shredded and hammer-milled to 3–8 mm particles. Direct bale-to-pellet is not feasible — size reduction is always the first step.

❓ What moisture content does straw need for pelleting?

✔ Optimal moisture for straw pelleting is 12–15%. Below 10%, pellets are fragile. Above 17%, the die can block and pellets develop surface cracks.

❓ How much output can I expect from a straw pellet mill?

✔ A 132 kW ring-die pellet mill typically produces 1.2–1.8 t/h of straw pellets. A 22 kW compact system (e.g. miniPelleter 22) produces 200–350 kg/h of straw pellets.

❓ What is the difference between hay pellets and straw pellets?

✔ Hay pellets retain nutritional value (protein, digestible fiber) and are used as animal feed. Straw pellets have lower nutritional value but higher fiber — used primarily for energy or bedding. Both require similar processing, but hay needs gentler conditioning to preserve nutrients.

❓ Do I need a binder to make straw pellets?

✔ Generally no — mechanical friction and natural lignin content in straw provide sufficient binding at the right moisture and temperature. For very dry or low-lignin material, 1–3% starch or molasses can be added as a binder.

Conclusion: Efficient Pellet Production for Modern Farming and Biomass Business

Producing pellets from hay and straw transforms a low-value, bulky agricultural residue into a premium, high-density product with multiple commercial applications. With proper size reduction, precise moisture control, and the right pellet machine, farmers and biomass processors can achieve consistent, EN-standard quality output.

The economics are compelling: straw worth €20–30/ton as loose bale can be converted into pellets worth €120–600/ton depending on the application — a 5–20× value multiplier from a single processing step.

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Explore our range of straw-processing solutions at www.minipelleter.com.