Why the Machine Matters
A skilled roaster can produce good coffee on a mediocre machine. But even the most skilled roaster is constrained by the equipment’s thermal dynamics, airflow design, energy efficiency, and control precision. The choice of roasting machine determines the range of profiles available, the batch-to-batch consistency achievable, the energy cost per kilogram roasted, and—increasingly important—the environmental compliance of the operation. Understanding the major manufacturers and their engineering approaches is essential for anyone purchasing, operating, or evaluating commercial roasting equipment.
The commercial roasting equipment market is concentrated among a small number of established manufacturers and a growing tier of newer entrants. Each brings a different engineering heritage, and the differences are not cosmetic—they reflect fundamentally different approaches to how heat is generated, transferred to the coffee, and managed throughout the roast cycle.
Probat
Probat is the oldest and largest coffee roasting equipment manufacturer in the world. Founded in 1868 in Emmerich, Germany, Probat has been building roasting machines for over 150 years and has installed more commercial roasting equipment globally than any other manufacturer. The company’s machines are the default reference point for the industry—when roasters talk about “conventional drum roasting,” they’re usually describing a Probat or a machine that follows Probat’s design principles.
Probat’s core product line centers on the classic single-drum design: a horizontal cylindrical drum rotates inside a housing, with a gas burner providing direct heat below and heated air drawn through the drum by an exhaust fan. The heat transfer is a combination of conduction (beans contacting the hot drum surface), convection (heated air flowing through the bean mass), and radiation (infrared energy from the drum walls and housing). The ratio of conduction to convection varies with drum speed, airflow settings, and gas input, giving the roaster meaningful control over the roast profile.
Key Probat models include:
Probatone series (5, 12, 25, 60 kg): The workhorse of the specialty industry. The Probatone 12 (12 kg batch capacity) is arguably the most common specialty roasting machine in the world. It offers precise manual gas and airflow control, robust construction, and a thermal mass that provides stable, forgiving roast dynamics. The Probatone series is known for its “Probat character”—a warm, rounded, full-bodied roast profile that some attribute to the relatively high conduction ratio of the drum design.
P-Series (P05, P12, P25): Probat’s updated platform with improved energy efficiency, digital control integration (compatible with Cropster and other profiling software), and refined airflow management. The P-series retains the traditional drum architecture but adds variable-frequency drive (VFD) drum speed control, allowing the roaster to adjust the conduction-to-convection ratio in real time during the roast.
UG-Series (15, 22, 45, 75, 120 kg): Probat’s large-scale production machines, used by commercial roasters processing hundreds of thousands of kilograms annually. These machines are engineered for throughput consistency rather than artisan profiling, with automated control systems and integrated afterburners for emissions compliance.
Probat machines are expensive. A new Probatone 12 runs $40,000 to $60,000 depending on configuration. The UG series starts above $100,000 and scales into the hundreds of thousands for the largest models. The used market for Probat equipment is active and well-established, with refurbished Probatone machines commanding $20,000 to $35,000 depending on age and condition.
Loring
Loring Smart Roast, based in Santa Rosa, California, represents the most significant engineering departure from traditional drum roasting in the commercial market. Founded by Mark Loring in 2003, the company’s machines use a single-burner, fully convective roasting system with integrated smoke elimination—a design that differs fundamentally from the drum-and-burner approach used by every other major manufacturer.
In a Loring roaster, the coffee sits in a stationary or slowly rotating drum while heated air is recirculated through the bean mass by a powerful fan. The single burner heats the air in a combustion chamber separate from the roasting drum; the hot air is then directed through the coffee, exits the drum carrying moisture and chaff, passes through a cyclone separator (which removes chaff), returns to the combustion chamber (where smoke and volatile organic compounds are incinerated by the burner flame), and is reheated before flowing through the coffee again. This closed-loop recirculation system means the burner serves double duty: heating the roasting air and functioning as an afterburner for emissions control.
The implications are significant:
Energy efficiency: Loring machines use approximately 50 to 80% less fuel than comparable-capacity drum roasters because the recirculated air retains residual heat rather than exhausting it. The energy savings are substantial at production scale—a high-volume roaster switching from a traditional drum machine to a Loring can reduce annual fuel costs by tens of thousands of dollars.
Emissions compliance: The integrated smoke elimination system means Loring roasters require no external afterburner or catalytic oxidizer for emissions compliance. In jurisdictions with strict air-quality regulations (California, parts of the EU, urban areas with odor ordinances), this eliminates a $30,000 to $80,000 afterburner investment and the associated installation and maintenance costs.
Roast profile character: The fully convective heat transfer produces a different profile dynamic than drum roasting. Without conductive heat from a hot drum surface, the roast is driven entirely by air temperature and flow rate. Roasters accustomed to drum machines describe the Loring profile as “cleaner” and more transparent—less of the body and warmth associated with conductive drum roasting, more clarity and acidity preservation. Whether this is an advantage depends entirely on the roaster’s stylistic goals.
Control precision: Loring machines use a PLC (programmable logic controller) with touchscreen interface, allowing the roaster to program and replicate profiles with high precision. The system can modulate burner output, fan speed, and drum speed simultaneously based on pre-programmed curves or real-time adjustment.
Loring models include the S7 Nighthawk (approximately 7 kg batch), S15 Falcon (15 kg), S35 Kestrel (35 kg), and S70 Peregrine (70 kg). Pricing starts around $65,000 for the S7 and scales to $250,000+ for the S70. The total cost of ownership, factoring in energy savings and eliminated afterburner requirements, can make the Loring competitive with or cheaper than a traditional drum machine plus afterburner over a 5 to 10 year operating horizon.
Giesen
Giesen Coffee Roasters, founded in 2006 in Ulft, the Netherlands, has become the fastest-growing manufacturer in the specialty segment over the past decade. The company’s machines follow the traditional drum-roasting architecture but with modern engineering refinements—tight manufacturing tolerances, stainless-steel construction, integrated data logging, and compatibility with major profiling software platforms.
Giesen’s product line is broad, covering batch sizes from 1 kg to 120 kg:
W1A, W6A (1 kg, 6 kg): Small-batch machines popular with sample roasters, home roaster-to-professional transitions, and micro-roasteries. The W6A in particular has become a staple of the small-batch specialty market, offering full-featured drum roasting at a price point ($15,000 to $20,000) that is accessible to startup operations.
W15A, W30A, W45A (15, 30, 45 kg): Mid-scale production machines. The W15A is Giesen’s equivalent to the Probatone 12—a 15 kg batch machine that handles the needs of a medium-volume specialty roaster. The W30A and W45A serve larger operations or roasters who prefer fewer, larger batches.
W60A, W120A (60, 120 kg): Large-scale production machines for high-volume operations.
Giesen machines are known for responsive thermal dynamics—they heat up and cool down faster than comparable Probat machines, which some roasters prefer for short-batch production and rapid profile adjustment. The flip side is that faster thermal response can be less forgiving of operator error; the thermal mass that makes a Probat “stable” also makes it “slow to respond,” and which characteristic you prefer depends on your roasting style and production rhythm.
Giesen’s pricing is generally 15 to 30% below Probat for comparable capacity, which has driven adoption among cost-conscious specialty startups. Build quality and reliability are well-regarded, though the company’s relative youth means the long-term durability track record (20+ years of continuous operation) is not yet established in the way that Probat’s is.
Diedrich
Diedrich Manufacturing, based in Sandpoint, Idaho, has a long history in the American specialty coffee market. The company’s machines are known for a distinctive design feature: the infrared (IR) drum burner. Unlike conventional drum roasters where a flame heats the drum from below, Diedrich machines use an infrared radiant burner that heats the drum wall through radiation, producing a more even heat distribution across the drum surface and reducing the hot spots that can cause scorching or tipping.
The IR burner design gives Diedrich machines a characteristic roast profile: even development with minimal surface damage, producing clean cups with good body. The radiant heat transfer is gentler than direct flame contact, and many Diedrich operators report that their machines produce a “softer” roast character—less aggressive Maillard browning than direct-flame machines at the same color endpoint.
Key Diedrich models include the IR-1 (1 kg), IR-3 (3 kg), IR-5 (5 kg), IR-12 (12 kg), and IR-24 (24 kg), with larger custom machines available. Pricing is competitive with Probat—the IR-12 runs approximately $35,000 to $50,000 depending on configuration.
Diedrich’s market position has been challenged by Giesen and Loring in recent years, but the brand retains loyal operators who value the IR burner’s profile characteristics and the company’s American manufacturing and service infrastructure.
Mill City Roasters
Mill City Roasters, based in Minneapolis, Minnesota, occupies a specific niche: accessible, well-built drum roasters at price points 30 to 50% below the European manufacturers. The company imports machines manufactured to their specifications in Asia (primarily China and Taiwan) and provides US-based service, support, and training.
Mill City’s product line includes machines from 500 grams to 30 kg batch capacity. The most popular models are the 1 kg, 3 kg, 6 kg, and 10 kg machines, which serve the home-to-professional transition market and small commercial operations. Build quality is solid if not at the level of Probat or Giesen—the machines use cast-iron drums, gas-fired burners, and standard thermocouple instrumentation compatible with Artisan roasting software.
Pricing is the primary differentiator. A Mill City 6 kg roaster runs approximately $8,000 to $12,000—roughly half the price of a comparable Giesen. For startup roasters with limited capital, this price difference is often decisive. The trade-off is in refinement: Mill City machines are functional and capable but lack the precision machining, VFD drum control, and advanced airflow management of premium European machines.
Has Garanti
Has Garanti, based in Istanbul, Turkey, is one of the largest roasting equipment manufacturers globally by unit volume, though less well-known in the North American specialty market than in Europe, the Middle East, and Asia. The company manufactures a full range of drum roasters from 1 kg shop roasters to 600 kg industrial machines, plus a line of fluid-bed (hot air) roasters.
Has Garanti machines are competitively priced, well-built, and widely distributed through a global dealer network. Their shop roaster line—small machines designed to roast in a retail environment where customers can watch the process—is particularly popular in the Turkish, Middle Eastern, and Southeast Asian markets where in-store roasting is a cultural tradition.
For the specialty market, Has Garanti’s mid-range machines (15 to 60 kg) compete with Giesen on price and feature set. The company has invested in profiling-software compatibility and modern control interfaces to address the specialty segment’s requirements.
Drum vs. Recirculation: The Core Design Decision
The choice between a traditional drum roaster and a recirculation machine (primarily Loring) is the most consequential equipment decision a roasting operation can make. The differences extend beyond roast profile into operations, maintenance, and economics.
Heat transfer mechanism: Drum roasters use a combination of conduction (30-50%), convection (40-60%), and radiation (5-15%). The conductive component—heat transferred from the hot drum wall to beans in direct contact—produces a characteristic body and warmth in the cup. Recirculation machines use nearly 100% convection, producing cleaner, more transparent cups but with potentially less body.
Operator interaction: Drum roasters typically offer manual control of gas, airflow, and drum speed, with the roaster making real-time adjustments based on bean temperature, rate of rise, color, sound, and smell. Recirculation machines automate more of the process—profiles can be pre-programmed and the PLC manages the execution. The drum requires more skill; the recirculation machine requires more programming.
Emissions and afterburners: Traditional drum roasters exhaust smoke, chaff, and volatile organic compounds (VOCs) through a stack. In most urban and suburban locations, regulatory compliance requires an afterburner (thermal oxidizer) or catalytic converter to destroy these emissions before they enter the atmosphere. Afterburners add $30,000 to $80,000 to installation costs and consume significant additional fuel. Loring’s integrated recirculation system eliminates this requirement.
Energy consumption: Recirculation machines use 50 to 80% less fuel than drum roasters because they recapture exhaust heat. At production volumes above approximately 500 kg per week, the fuel savings become significant—potentially $10,000 to $30,000 per year depending on fuel costs and production volume.
Maintenance: Drum roasters are mechanically simpler—fewer moving parts, no recirculation ducting, no cyclone separators. Maintenance is primarily drum bearing replacement, burner service, and thermocouple calibration. Recirculation machines have more complex airflow systems that require regular cleaning (chaff accumulation in ducts and cyclones) and more sophisticated burner maintenance.
Capacity Ranges and Choosing the Right Size
Roaster capacity selection is a function of production volume, batch frequency, product mix, and growth projection. The general rule: buy a machine that can handle your projected volume at 60 to 70% of maximum capacity utilization, leaving headroom for growth and for the reality that not every batch will be a full batch.
1 to 3 kg: Sample roasting, R&D, and very small retail operations. These machines are essential for evaluating green coffee purchases and developing profiles that will be scaled to production machines. Every roasting operation above micro-scale needs a sample roaster regardless of production machine size.
5 to 7 kg: Small specialty roasters doing 25 to 100 kg per week. This is the startup range—sufficient for a small cafe’s house roasting program or a beginning wholesale operation. Expect to roast 4 to 10 batches per day at this capacity.
12 to 15 kg: The specialty workhorse range. Suitable for operations doing 100 to 500 kg per week. A 12 kg roaster running 6 to 10 batches per day covers the production needs of a mid-size wholesale roaster. This is the most competitive capacity range across manufacturers and the most common size in the specialty industry.
25 to 45 kg: High-volume specialty and commercial-specialty operations doing 500 to 2,000 kg per week. At this scale, batch frequency is lower (fewer roasts per day for the same output), which reduces operator fatigue and allows more time for quality control between batches.
60 to 120 kg: Large commercial operations, private-label roasters, and co-packing facilities. Machines at this capacity are less common in pure specialty operations but serve the high-quality commercial segment where consistency at volume is the priority.
The Afterburner Question
Afterburners (thermal oxidizers) deserve specific attention because they significantly affect the total cost and feasibility of a roasting installation. An afterburner is a secondary combustion chamber, mounted in the exhaust stack, that incinerates smoke particles and VOCs before they enter the atmosphere. They’re required by air-quality regulations in most urban and many suburban jurisdictions in North America, the EU, and parts of Asia.
A standard thermal afterburner for a 12 to 15 kg roaster costs $30,000 to $50,000 installed, consumes additional gas fuel during operation (adding 20 to 40% to the roaster’s fuel consumption), and requires periodic maintenance. Catalytic oxidizers are more energy-efficient (they operate at lower temperatures using a catalyst to promote combustion) but cost more upfront ($40,000 to $70,000) and require catalyst replacement every 3 to 5 years ($5,000 to $10,000).
For many startup roasters, the afterburner cost is the difference between a feasible business plan and an infeasible one. This economic reality is a significant driver of Loring adoption—the integrated emissions system eliminates the afterburner entirely, and the total equipment cost (Loring machine plus no afterburner) can be comparable to or less than a drum machine plus afterburner in jurisdictions where emissions compliance is mandatory.
Some roasters avoid the afterburner question by locating in agricultural or industrial zones with less stringent air-quality requirements. This works until the neighborhood changes, regulations tighten, or a complaint is filed. The long-term trend in urban areas is toward stricter emissions standards, and any roasting installation should plan for eventual afterburner requirements even if current zoning doesn’t mandate one.
Making the Decision
Choosing a roasting machine is a 10 to 20 year commitment. The machine will outlast your current menu, your current staff, your current lease, and possibly your current business plan. The decision framework should weight:
Profile goals: What kind of coffee do you want to roast? If you value body, warmth, and traditional roast character, a drum machine (Probat, Giesen, Diedrich) is the natural choice. If you prioritize clarity, transparency, and origin expression, a Loring or other convective machine may better serve your style.
Production volume: Match capacity to projected volume with growth headroom. Buying too small is a more expensive mistake than buying too large—outgrowing a machine within 2 to 3 years means purchasing a second machine, managing two different roast profiles, and dealing with the space and utility requirements of two installations.
Regulatory environment: Check local air-quality requirements before selecting equipment. If an afterburner is required, factor that cost into the total comparison. A Loring at $80,000 with no afterburner may be more cost-effective than a Probat at $50,000 plus a $45,000 afterburner.
Service and support: A roaster that breaks down during peak production season is a crisis. Evaluate the manufacturer’s service infrastructure, parts availability, and response time in your region. Probat and Giesen have extensive global service networks. Loring’s service is US-centric but expanding. Mill City provides US-based support. Has Garanti’s service varies by region.
Software integration: If data-driven roasting is important to your operation (and it should be), verify that the machine integrates with your profiling software of choice. Most modern machines support Cropster, Artisan, or proprietary profiling platforms, but the quality of integration varies. Native integration (where the profiling software reads directly from the machine’s control system) is significantly more reliable than aftermarket thermocouple installations.
Resale value: Probat and Loring machines hold their value well on the used market. Giesen is building resale track record. Other brands may depreciate faster, which matters if your business plan includes equipment upgrades on a defined timeline.