About Fluid Bed Roasting

About Fluid Bed Roasting

Also known as Hot Air Roasting or Air Roasting

ASHE Roasters use Fluid Bed Technology and can be classified as a hot air roaster or air roaster.  Fluid bed air roasting or hot air roasting is a superior form of coffee roasting that was technically not possible when legacy drum style coffee roasting systems were originally developed in the 1800’s.  Not until efficient electric blowers and heating elements became commercially available, was it possible to develop a cost effective production worthy fluid bed roasting system.  Modern fluid bed roasting equipment uses a stream of high velocity hot air to levitate the coffee beans and suspend them momentarily in a bath of hot air, allowing uniform heating of the individual beans.  Air roasting with a purpose built ASHE hot air roasting system, designed specifically for roasting coffee, provides a consistent uniform roast batch after batch.

As the coffee beans are levitated in the the hot air stream, they roll and tumble in the super heated air, which causes unwanted by-products of the roast (burnt chaff, under size or broken beans, etc) to be expelled by the convective/lifting action of the hot air.  In addition, our fluid bed hot air roasters come with forced air cooling outside the roast chamber, which gives almost instantaneous cooling and allows for the next roast to be loaded in the roast chamber immediately after pouring out the fresh roasted batch into the cooling system.  This provides for an efficient production process for high volume roasting with minimal production labor.

The major differences between Fluid Bed Roasting and Drum Roasting

Unwanted By-Products Removed

The high velocity hot air stream, used to levitate coffee beans in a fluid bed roaster, liberates unwanted chaff, dust and other undesirable organic by-products and particulates from the coffee beans.  These unwanted by-products are lifted vertically and removed from the roasting environment.  In the ASHE system, this unwanted debris is forced out of the roasting chamber and evacuated using our high performance chaff collector and swivel hood assembly.  Chaff and other debris, if allowed to roast along with the coffee, can contribute to undesirable after tastes and bitterness.

More Flavor

The longer coffee beans are roasted, the more the flavor oils are reduced. Drum roasters can take up to 20 minutes to roast a 10 lb batch.  The ASHE 10 lb coffee roaster take approximately 10 minutes to produce a medium roast.   The larger 22 lb ASHE Roasters using our High Residence Time (HTR) heating chamber will produce a medium roast from 22 lbs of Green Beans in less than 15 minutes.

Consistent Temperature

The ASHE roaster provides a consistent temperature to all the beans in a batch. Because of the “fluid” motion formed by the hot air being pumped in, the beans rotate up and down and around in the air flow in the roasting chamber constantly, so that each bean is roasted to exactly the same degree. In a drum roaster, the beans are stirred with a mechanical arm which does not distribute the beans evenly in the heat, causing some beans to be over-roasted.

Forced Air Cooling System

The ASHE roaster comes standard with a forced air cooling system. In most fluid bed roasters the beans are cooled in the roast chamber by means of a water spray. With the ASHE system, the beans are tipped into the cooling system as soon as the roast is completed, and cool down to a point where no further roasting is happening within seconds, and continue to cool to touchable within just a few minutes. This give the roaster the advantage that a new batch of coffee can be roasting in the roast chamber immediately after the previous one has been tipped out, allowing for continuous roasting. The cooled coffee is removed from the cooling tray long before the next batch is ready to tip. The cooled coffee can then be immediately packed to preserve freshness.

Easy To Control

Fluid bed roasting is much easier to control than with a drum roaster. The operator can observe the coffee at all stages, rather than pull a sample every few seconds to see where they are. Roasting can be done entirely and precisely by temperature, if desired, though most roast experts will want to use their eye, nose and ears as well, that is how one becomes a roast expert rather than just a roast operator. However that level of expertise is not necessary with a fluid bed roaster, the way it is with a drum roaster, just much more fun to do.

All roasters are configured for your specific needs.

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For More Information & Pricing



10 lb Coffee Roaster and Cooler – $7,995

Power Requirements: 240 volts AC, 45 amps for heaters;120 volts AC, 15 amps for blower, cooler, and controls.
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12 lb Coffee Roaster and Cooler – $9,495

Power Required: 208 Volt, 3 Ph AC, 35 amps for heaters;120 volts AC, 15 amps for blower, cooler, & controls.
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15 lb Coffee Roaster and Cooler – $10,995

Power Requirements: 240 volts AC, 65 amps for heaters;120 volts AC, 20 amps for blower, cooler, and controls.
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22 lb (10 kg) Coffee Roaster and Cooler – $13,495

Power Requirements: 240 Volts, 1-Ph, 80 Amps OR 208 Volts, 3-Ph, 50 Amps for heating circuit; 120 Volts, 20 Amps for blower, cooler and controls.
Roast Profile Chart: Click here
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Chaff Collection System – $4,495

Sold Separately: Includes cyclone 220/240V, 8 amp 1 Phase, 2HP blower, Chaff Collector, Swivel hood assembly for mounting to roaster & flexible ducting.
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