How to Dry Star Anise?

1. Background
Star anise, the mature fruit of a plant in the Magnoliaceae family, is an indispensable spice in Chinese cuisine. It contains 5%-8% aromatic oil, approximately 22% fatty oil, as well as proteins and resins, and is widely used in cooking and food processing. Star anise dried fruit must be harvested after late August and completed by mid- to early-October to ensure quality. Generally, 3-4 jin (100 grams) of fresh fruit can be processed into 1 jin (100 grams) of dried fruit.

There are two main traditional methods for drying star anise: direct sun drying, where fresh star anise fruit is spread directly on a drying yard and dried in sunlight for four days. The other method, post-wilt sun drying, involves placing the fresh fruit in 90-100°C water, stirring for four to six minutes, then removing it and drying it again. These traditional methods are highly dependent on weather conditions, require extensive manual turning, and occupy a large drying area.

During rainy weather, growers resort to traditional drying methods: indoor ovens, ignited with charcoal, and baked at around 50°C, drying a batch in about two days. This method makes precise temperature control difficult, leading to uneven quality of star anise, and even blackening or scorching.

2. Jinlu Machinery Customization

This 12m x 2.3m wide, six-layer biomass pellet charcoal mesh belt dryer, custom-made for a customer in Guangxi, is a modern device specifically designed for the drying characteristics of star anise. This mesh belt dryer features a multi-layer design, with the material evenly spread across the mesh belt, which is then driven back and forth within the dryer by a transmission mechanism. Hot air flows through the material, and moisture vapor is expelled through dehumidification holes, achieving drying. The interior of the dryer consists of multiple layers of stainless steel mesh belts. A blower delivers pure hot air from the heat exchanger to the bottom of the dryer, where it first passes through the bottom layer of mesh belts, exchanging heat with the dry material and removing some moisture. The air then passes through each layer of mesh belts, creating a countercurrent heat exchange with the material. This countercurrent heat exchange method fully utilizes hot air, resulting in rapid drying and dehydration, high efficiency, and minimal energy consumption.

03 Star Anise Drying Process

Withering is a critical step in preserving the star anise’s luster. The water temperature for withering should be maintained at 90-100°C, and the fruit should be stirred for 4-10 minutes, until the color changes from green to light yellow.

Drying Process:

In the first stage, the temperature is set to 60°C for one hour. No dehumidification is required, primarily to control color.

In the second stage, the drying mode is switched to drying + dehumidification mode, with the temperature set to 55°C for three hours. Extensive dehumidification is required during this stage.

In the third stage, maintaining the drying + dehumidification mode, the temperature is lowered to 50°C for three hours, and extensive dehumidification continues.

In the fourth stage, the temperature is further lowered to 45°C for three hours. During this stage, the moisture content is relatively low, allowing for gradual dehumidification.

In the final stage, the drying mode is switched back to drying mode, with the temperature raised to 65°C for two hours, completing the drying process.

The entire drying process takes approximately 12 hours, making it far more efficient than traditional air-drying or traditional drying methods.

With the introduction of customized large-scale drying equipment like Jinlu Machinery, star anise processing is gradually moving away from the traditional “weather-dependent” model. Mechanized drying not only ensures consistent star anise quality but also enables Guangxi’s star anise industry to move towards standardization, scale, and branding. This ancient spice, empowered by modern technology, is now revitalized.