Spices are a very valuable product which is usually produced in small industrial quantities. While it is a very wide range of products with varying properties, spices are commonly won from the flowers, leaves or roots of plants and used for their intense flavour in the seasoning of food. Grinding these raw products into spice powders makes the aroma accessible and allows improved dosing and storage properties.
Many Bauermeister mills are established all around the world for the grinding of various spices. For every spice there is an optimal mill and combination of parameters depending on the desired fineness and necessary cooling. The right mill setup and integration of the mill into a production plant depend on the general conditions as well as on the individual requirements of every plant operator. For the evaluation of the criteria Bauermeister specialists are available for a competent consultation.
The flexibility of different grinding tools and rotor speeds allow a range of different spices to be processed on the Bauermeister Universal Mill UM. Due to this it is a very commonly used mill in the spice industry, often in combination with L-CO2 cooling nozzle. Often a mill-sieve circuit is installed where the desired product fractions can be obtained from the sieve and the oversized product is send back to the mill.
Large parts of the spice plant such as roots or leaves need to be pre-crushed before milling. Design especially for the pre-crushing of spices, Bauermeister offers the US11 cutting mill, a small compact grinding plant can be easily combined with the UM for an optimal grinding result.
A common problem occurring while grinding most spices is the risk of flavour loss. Minimal heat treatment of spices will lead to the evaporation of the flavour critical essential oils. During grinding the high input of mechanical energy, necessary for grinding of the spices into a powder, will always entail the introduction of heat into the product. Due to this, it is essential to include a cooling system in a spice grinding plant in order to remove the heat introduction and minimise the flavour loss.
The wide range of spice properties demands a great flexibility of mills and cooling systems. To account for this, Bauermeister offers three different systems that can be combined with all our grinding plants for cooling of the grinding process: cold process air, liquid gas cooling of process air (L-CO2 or L-N2) or cryogenic grinding plants.
In most cases it is sufficient to use a minimal amount of cooling that only ensures isothermal grinding (product inlet temperature equals outlet temperature). Further cooling would be an unnecessary expense and may additionally lead to problems such as condensation. Cryogenic grinding with product temperatures of up to - 50 to - 100 °C (achieved by L-N2 cooling) may be necessary for some, especially fat containing spices such as nutmeg, mustard or coriander and can also be achieved on Bauermeister mills.