De-lumping and grinding coffee: what industrial solutions to ensure a homogeneous and controlled grind ?

The quality of coffee, as perceived in the cup, heavily depends on the consistency of its grind.

A homogeneous particle size ensures controlled extraction, whether for espresso, filter, or capsule coffee.

For manufacturers, this homogeneity requires perfectly controlled grinding, preceded if necessary by a de-lumping phase to eliminate agglomerates formed during storage or drying.

Between constraints of throughput, precision, cleaning between batches, and dust management, the selection of grinding equipment is strategic.

Palamatic Process offers custom solutions for industrial de-lumpers and grinders, capable of processing coffee without overheating or aromatic alteration, while ensuring great production flexibility.

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1.1 Objective: mastering extraction, quality, and product consistency

In the world of coffee, particle size — meaning the average size and distribution of particles obtained after grinding — plays a fundamental role in the quality of the finished product.

In industrial production, poorly controlled grinding can impact:

• The taste of the coffee: excessively fine particles lead to over-extraction (bitter taste), while excessively coarse particles lead to under-extraction (acidic or bland taste).
• Consistency in the cup: in large-scale production, consumers expect a stable sensory profile. A heterogeneous grind generates noticeable variations.
• Machine compatibility: grinds intended for capsules, espresso machines, or filters have precise requirements. An irregular grind can block a capsule or speed up water passage.

This is why industrial roasters and coffee packers invest in grinding systems capable of ensuring a very narrow particle size distribution, adapted to each application, with quality controls for each batch.

1.2 Influence of particle size on cup profiles (espresso, filter, capsule)

Each coffee extraction method requires a specific grind size:

• Espresso grind: very fine (approximately 200–300 μm), allowing for short extraction under high pressure. A too irregular grind leads to “channeling” and an unbalanced espresso.
• Filter grind: coarser (600–900 μm), promoting slower infusion with gentle aroma extraction.
• Capsules: they require a fine and regular grind, often specific to the machines (Nespresso®, Dolce Gusto®, etc.). A slight variation can be enough to alter the balance of the coffee in the cup.
• Turkish or cold brew coffee: in the first case, the grind must be almost powdery (<150 μm), in the other, very coarse.

Hence the importance of a calibrated and reproducible grinding to ensure intra-batch and inter-batch homogeneity.

It is also a commercial issue: some specifications from large retailers impose very tight tolerances.

1.3 What are the risks of an irregular grind?

Poorly controlled grinding in industry can have direct consequences:

• Sensory inconsistency: the taste of the coffee changes from one batch to another, creating customer dissatisfaction.
• Production rejects: non-compliant batches must be repackaged, reprocessed, or destroyed.
• Technical problems: filter clogging, overpressure in capsules, excessive dust.
• Loss of aromas: over-ground fines oxidize more quickly, reducing the perceived quality of the product.
• ATEX risks: the generation of fine volatile dust increases the risk of explosion in an uncontrolled environment.

A homogeneous grind is therefore a guarantee of overall process performance, customer satisfaction, and quality compliance.

To achieve this, it is essential to equip oneself with adapted grinding technologies … but this often begins with an underestimated step: de-lumping.

2.1 Objective: preparing coffee for stable grinding

In industrial production, grinding does not always start with perfectly fluid and uniform coffee.

During storage, transport, or after certain processes like drying, the material can form compact lumps, especially if it is slightly damp, oily, or compressed.

These agglomerates greatly disrupt the operation of grinders:

• The feed becomes irregular, causing jolts or blockages.
• The grinder must exert additional effort, which increases mechanical wear and the risk of breakdown.
• The final particle size becomes inconsistent, as the product does not enter the reduction zone homogeneously.

This is why the de-lumping step is often indispensable upstream of grinding, especially for coffee stored in bulk, in silos, or big bags.

It ensures a regular feed, a sine qua non condition for obtaining a uniform grind.

2.2 Industrial de-lumping: breaking agglomerates without destroying the product

De-lumping does not aim to grind, but to de-agglomerate without altering the product's characteristics.

At Palamatic Process, industrial de-lumpers are designed to:

• Break compact blocks formed in ground coffee (especially in the presence of natural oils).
• Ensure a constant flow rate, often at the outlet of a big bag, silo, or buffer hopper.
• Avoid overheating or crushing, thanks to slow-speed rotors.
• Be integrated directly under discharge stations, such as those used for coffee big bags.

The EC50 and EC70 models, for example, allow gentle processing, with interchangeable grids to control the size of the returned pieces.

All this with a reduced footprint, quick cleaning, and compatibility with ATEX environments if necessary.

2.3 Should coffee always be de-lumped before grinding?

Not systematically, but in 95% of industrial lines, de-lumping quickly becomes a key asset to:

• Ensure a linear feed to the grinder;
• Protect the grinding mechanism against overloads;
• Stabilize the particle size quality of the final batch;
• Reduce jolts in downstream weighing (in case of post-grinding weigh dosing).

De-lumping is therefore a preventive step that secures the rest of the process.

It is particularly useful for flavored coffees, dark roasts (oilier), or materials PDPNfrom distant production sites.

3.1 Objective: adapting the grinder to the type of coffee and target particle size

The choice of industrial grinder type depends on several factors:

• the type of coffee to be processed (whole beans, roasted, pre-cooked...)
• the desired grind size (filter, espresso, capsule, Turkish)
• the hourly production capacity
• product-related constraints (oil content, residual moisture, ATEX risks)
• the expected level of particle size precision (narrow distribution of particle sizes)

Depending on these criteria, several technologies can be used to obtain a regular and stable grind, without generating overheating or excess fines.

3.2 Comparison: hammer mills, pin mills, disc mills, impact mills...

Here is a comparison of the main grinding technologies used for coffee in an industrial setting:

At Palamatic, the UM model is particularly suitable for food powders, including coffee.

It ensures a fine and regular grind, with different settings depending on the recipe.

3.3 How to choose the right coffee grinding system?

Here are the key questions to ask before choosing a coffee grinding technology:

• What is the product's destination?
  • Capsules, espresso, sticks: very fine and regular grind → pin or disc mill
  • Filters or bulk: medium grind → hammer or universal mill
• What is the expected rate?
  • High rate = need for robustness → hammer or disc mill
  • Low throughput, high precision = pin or cryogenic mill
• Is the coffee oily or flavored?
  • Yes → beware of clogging → prefer tools with easy cleaning
• Are there ATEX constraints?
  • Fine dust = zone 21/22 → certified equipment essential
• Need for flexibility? Multiple recipes?
  • → opt for a grinder with modular components (screens, speed...)

The ideal solution is to conduct actual product trials in a test center like that of Palamatic Process, to validate your coffee's behavior on several types of grinders.

4.1 Objective: preserving the organoleptic qualities of coffee

Coffee is a fragile product.

During grinding, the material releases oils and volatile compounds responsible for its characteristic aromas.

If the grinder overheats, these compounds degrade or evaporate prematurely, altering the product's aromatic profile.

Furthermore, the finest particles generated during grinding (the "fines") are very reactive to oxidation.

A grind that is too hot or too exposed to ambient air quickly loses freshness.

That is why it is essential, in an industrial context, to avoid any mechanical overheating, while maintaining good grinding efficiency.

4.2 Palamatic solutions to prevent overheating and oxidation

Palamatic Process offers several concrete approaches to limit thermal effects and ensure quality grinding:

• Adjustable rotation speed: Palamatic grinders can operate at speeds adapted to the material to reduce friction.
• Online temperature control: integrated probe to alert in case of thermal drift.
• Anti-overheating materials: optimized design of grinding tools (treated steel, polished surfaces).
• Integrated sieving: to avoid unnecessary regrinding that overheats the material.
• Airflow cooling: on some models, a regulated airflow can be injected to stabilize the grinding temperature.
• PLC-controlled throughput via Pal'Touch®: to avoid occasional mechanical overloads.

Optionally, it is also possible to install a grinding system under a controlled atmosphere (nitrogen), useful for certain very sensitive powders, especially flavored or premium organic coffees.

4.3 Should grinding in an ATEX environment or under nitrogen be considered?

Yes, in many cases.

Ground coffee generates fine, dry, organic dust — a potential ATEX risk if ventilation or suction conditions are insufficient.

Depending on the grinder type, rotation speed, processed volume, and product nature, installations can be classified as ATEX zones 21 or 22.

Palamatic offers grinders and de-lumpers that are:

• ATEX certified, with adapted electrical equipment;
• Dust-tight, with integrated suction or a dust removal ring;
• Prepared for operation under nitrogen, for complete inerting in a closed circuit.

These precautions not only aim for operator safety but also for aroma preservation: by limiting available oxygen, the oxidation of coffee's volatile oils is reduced.

5.1 Objective: quickly switching from one recipe to another

In a modern production line, flexibility has become a decisive criterion.

Many coffee manufacturers must manage multiple recipes or formats:

• different roasts (light, medium, dark),
• flavored coffees (vanilla, hazelnut…),
• organic or conventional products,
• grinds for espresso, filter, capsule...

However, these variations imply different grinding parameters.

To avoid prolonged downtime or adjustment errors, the grinder must allow for:

• a quick recipe change (speed, screen, tool distance…),
• an intuitive configuration via PLC (such as Pal’Touch®),
• an adaptable feed (mobile hopper, gravity feed, or screw conveyor).

This is also an asset for meeting demand peaks (holidays, promotions, launch of a new range).

5.2 Easy cleaning and reduction of cross-contamination

Since coffee is a sensitive product, line cleaning is paramount:

• to avoid batch mixing (especially between organic and conventional),
• to eliminate residues of fatty or flavored materials,
• to comply with IFS/BRC/HACCP standards in the food industry.

Palamatic grinders are designed with a clear objective: facilitate frequent cleaning between each cycle or batch:

• Quick access to grinding zones: tool-free disassembly (EasyClean),
• Smooth or mirror-polished finishes in 304L or 316L stainless steel,
• CIP/SIP compatible surfaces on some models,
• Easily removable and replaceable screens and tools,
• Integrated suction to collect dust residues.

An easy-to-clean grinder also means less downtime, less labor, and more hygienic safety.

5.3 How to maintain an industrial grinder to ensure consistent performance?

Good coffee grinding also relies on the mechanical durability of the equipment.

A poorly maintained grinder can produce an irregular grind, overheat the product, or break down mid-production.

Here are the recommended best practices:

• Regular checks of clearances between moving parts,
• Scheduled replacement of impact tools or screens according to wear,
• Appropriate lubrication, especially for bearings,
• Leak tightness verification, especially in ATEX or humid zones,
• Automated monitoring (vibration, temperature) via Pal’Touch®.

Palamatic also offers preventive maintenance plans, as well as the supply of original spare parts and training for your production teams.

In the coffee industry, mastering particle size is much more than a technical detail: it is a strategic lever to guarantee consistent taste, optimal extraction, and loyal customer experience.

For this, it is not enough to grind — one must grind intelligently.

From preparatory de-lumping to choosing the adapted grinder (pin, hammer, disc), each step of the process must be designed to:

• ensure perfect grind homogeneity,
• preserve aromas and avoid overheating,
• reduce dust, losses, and rejects,
• facilitate recipe changes and cleaning,
• guarantee compliance with food safety standards and regulations (ATEX zones, traceability, hygiene).

At Palamatic Process, we design custom coffee grinding solutions, adapted to your throughputs, products, and industrial constraints.

Our de-lumpers, universal grinders, and suction/dust removal systems allow you to secure your production while increasing its added value.

📩 Do you want to optimize your coffee grinding line? Our team supports you in analyzing your needs, with real tests in our technical center.

👉 Contact us now for a personalized study.