The hammer mill is the best tool for processing spices, because of its operational flexibility, and the ability to control finished particle size. With the exception of high oil content spices such as nutmeg and mace (unless cryogenically frozen), the hammer mill is ideal a wide variety of spices, and dried herbs including: red pepper, white pepper, black pepper, coriander, cumin, cinnamon, oregano, thyme, cloves, and turmeric. Just to name a few.
The simplicity of the hammer mill makes it easily adaptable to the varying characteristics of different spices, and its versatility makes the hammer mill ideal for those processing more than one variety of spice. In addition, the processing mechanism of the hammer mill results in crushing by impact, instead of compression. As a result, spices are reduced to the exact desired finished particle size without significant heat increase that could cause loss of flavor or aroma.
The importance of exact finished particle size cannot be overstated when grinding spices. The perforated screen covering the discharge opening is the key hammer mill component that controls the finished particle size. Screen selection allows the processor to determine the largest allowable finished particle size. Material remains in the hammer mill's grinding chamber and continues to be pulverized until it is able to pass through the screen. Screens of varying sizes can be used interchangeable in the same mill.
A 1/8" perforated screen will produce a tea cut finished particle size. Whereas a 1/32" screen will produce a fine powder. The second component of size determination is the rotor speed. As the rotor spins, the hammers impact the material with great severity.
High rotor speed = increased number of hammer blows = finer particle size
Slower rotor speed = decreased number of hammer blows = coarser particle size
Very hard materials such as cloves, ginger and turmeric will require a higher rotor speed to produce the same finished particle size as softer materials like white and black pepper. An optional variable frequency drive electrical control allows the operator to easily adjust the rotor speed as needed for different applications.
Finally, the style of hammer mill is determined by infeed material characteristics and desired throughput rate. For softer and/or easier to process materials, a hammer mill with a nearly full circle screen is most suitable. The 300 degree screen coverage allows for the greatest throughput at the lowest horsepower.
Fibrous herbs and roots such as kava, cassava, yam, carrot and ginseng are best ground in a more traditional industrial hammer mill. This style of hammer mill contains an internal breaker plate that is the first point of contact when material enters the grinding chamber. Because of its ribbed construction, the breaker plate has a washboard effect, breaking down the material and thus making the pulverizing action of the hammers more efficient while reducing wear on the screens.
Both the full circle screen coverage hammer mills and the industrial hammer mills range in size from pilot scale to high production models. The size of the hammer mill and the recommended horsepower of the motor are determined by the processor's production goals.
For more information, visit: http://www.hammermills.com/industries-served-schutte-buffalo-hammermill/herbs-and-spices/herbs-and-spices/44-series-spice-grinder
Schutte-Buffalo Hammermill, LLC