Solvent-free Decaffeination with Power-Ultrasound

  • The conventional decaffeination process of coffee and tea requires the use of toxic solvents.
  • Ultrasonic decaffeination is an efficient intensification method the that allows to remove caffeine in a water-based extraction procedure without the use of harsh solvents.
  • Ultrasonic decaffeination is an economical, effective and green methods to produce high-quality decaffeinated coffee, tea and cocoa products.

Decaffeination with Ultrasonication

Caffeine is a water-soluble substance, so that water can be used for the removal of caffeine from coffee, tea and cocoa. Conventional decaffeination processes use a chemical as decaffeinating agent (such as methylene chloride, CO2, or ethyl acetate) to accelerate the process. By using ultrasonic water-based extraction in combination with activated charcoal as decaffeinating agent, a decaffeinated coffee, tea or cocoa product is prepared in an organic and environmentally-benign process.

Advantages of Ultrasonic Decaffeination

  • High-quality (premium coffee)
  • Solvent-free
  • Mild, non-thermal
  • Energy-saving
  • Rapid
  • Suitable for organic certified products
  • Fast RoI
  • Easy operation
  • Environmental-friendly

Ultrasonically Intensified Swiss Water Decaffeination

The ultrasonically assisted decaffeination is an intensification process of the so-called Swiss water decaffeination .
The Swiss water decaffeination process works on basis of dissolving and osmosis to remove caffeine from coffee beans, tea leaves and cocoa beans.
Integrating probe-type ultrasonicators into the Swiss Water decaffeination process involves incorporating sonication during specific stages of the process to enhance caffeine extraction. The Swiss water decaffeination process involves four major process steps. While the implementation of ultrasound for a more efficient decaffeination can vary depending on the specific setup and equipment, here is a general outline of how probe-type ultrasonicators are mainly integrated for process improvement:

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Ultrasonic extractor installed on a reactor for the decaffeination of tea and coffee
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Ultrasonic extraction is the superior method to produce cold-brew coffee from coffee ground. Sonication releases the flavour compounds and caffeine within seconds.

Ultrasonic Extraction of Caffeine and Brewing Cold-Brew Coffee

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  1. Soaking stage: The initial step in the Swiss Water decaffeination process involves soaking green coffee beans in hot water to create a flavor-charged water solution. During this soaking stage, a probe-type ultrasonicator can be used to apply sonication to facilitate the extraction of caffeine from the beans. Ultrasonication is well known for its capacity to intensify extraction processes from of bioactive compounds such as caffeine from plant materials. The mechanical forces of ultrasonic / acoustic cavitation perforate and disrupt cells and promote mass transfer. Thereby, caffeine is removed from the beans and released efficiently into the water. Due to these effects, sonication speeds the decaffeination process significantly up. The ultrasonically extracted caffeine is a valuable additive for food and beverages, e.g. energy drinks.
  2. Caffeine removal stage: After the initial soaking, the flavor-charged water containing caffeine is separated from the coffee beans. This water is typically passed through activated charcoal filters to remove the caffeine. The porosity of this filter is sized to only capture larger caffeine molecules, while allowing smaller oil and flavor molecules to pass through. This means the charcoal filter holds the caffeine, whilst the filtered water contains all the smaller bioactive substances, which are known to give coffee, tea and cocoa their distinctive aroma and nutritional value.
  3. Reabsorption stage: The decaffeinated beans, which have been stripped of caffeine and flavour molecules, are discarded. The caffeine-free flavor- and polyphenol-enriched water (also known as “Green Coffee Extract”) is highly valuable and is used to remove the caffeine from a fresh batch of still caffeine-containing coffee beans.
    Since this water is saturated with flavor molecules and other bioactive substances, these compounds cannot dissolve in the fresh batch of coffee beans. Thereby, only caffeine molecules are released from the coffee beans into the water and a decaffeination without removing aroma and other valuable phyto-chemicals. Once the flavor-charged water is free of caffeine, it is reused for extracting caffeine from a new batch of green coffee beans. This reabsorption stage can benefit from the use of probe-type ultrasonication, again. The green beans are soaked in the flavor-charged water, and ultrasonication is applied to facilitate caffeine extraction. The sonication helps enhance the penetration of the water into the beans, improving the extraction efficiency and reducing extraction time.
  4. Repeated reabsorption and drying: The reabsorption and sonication steps can be repeated multiple times until the desired level of decaffeination is achieved. After the final reabsorption, the decaffeinated coffee beans are typically dried, and the flavor-charged water is ready for reuse in the next batch.
The ultrasonically assisted water decaffeination is an excellent technique for decaffeination of organic, consciously produced coffee and tea.


Ultrasonic botanical extraction gives higher yields. The Hielscher UIP2000hdT, 2000 watts homogenizer is powerful enough to extract batches from 10 liters to 120 liters easily.

Ultrasonic Extraction of Botanicals - 30 Liter / 8 Gallon Batch

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Ultrasonicator UIP6000hdT for the industrial decaffeination of coffee beans, tea and cocoa. Ultrasonication facilitates and intensifies the Swiss Water Decaffeination process.

Ultrasonically-intensified Swiss Water Decaffeination: Industrial ultrasonicator UIP6000hdT for the continuous decaffeination

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Case Study of Ultrasonic Decaffeination of Coffee Beans

Ultrasonic probe UP400St for the efficient extraction of caffeine from coffee beans, tea and cocoa. Ultrasonication intensifies and improves the Swiss Water Decaffeination process.The study by Huamaní-Meléndez and Darros-Barbosa (2018) aimed to investigate the effect of ultrasound intensity, pulse, and temperature on the extraction of caffeine from Arabica coffee beans using an aqueous medium. The researchers used the Hielscher high-intensity ultrasound probe UP400S (400 watts; see picture left) and performed experiments at different intensities, pulse durations, and temperatures. They found that increasing the ultrasound intensity and pulse duration led to a higher caffeine extraction rate, but only up to a certain point, after which further increases did not significantly improve extraction. The optimal conditions for caffeine extraction were found to be an ultrasound intensity of 75 W/cm2, a pulse duration of 5 sec, and a temperature of 25°C. The study provides a specific protocol for using ultrasound to extract caffeine from coffee beans and suggests that this method could be an effective and environmentally friendly alternative to traditional decaffeination processes.

High-Performance Ultrasonicators for Solvent-Free Decaffeination

Hielscher Ultrasonics provides you with high-performance ultrasonicators for the mild, yet highly efficacious extraction and decaffeination processes. With ultrasound power from 50 to 16,000 watts per ultrasonicator, the Hielscher portfolio of ultrasonicators has the ideal ultrasonicator for you coffee brewing and decaffeination process!
As long-time experienced manufacturer and consultant for high-power ultrasonicators and their application, Hielscher is your partner for ultrasonically-assisted extraction processes. Hielscher ultrasonic processors are installed worldwide for applications in the food & beverage, pharma, and chemical industries.
We do not only supply high-power ultrasonic extractors, but we assist our customers also with our profound knowledge. Our customer service ranges from consultation and feasibility studies to process optimization and pilot equipment to the installation of ultrasonic systems on industrial scale.
Offering a broad range of ultrasonic processors and accessories (such as sonotrodes, flow cells and reactors), we can recommend you the most suitable system fulfilling the requirements if your process capacity and conditions. Installation and retro-fitting into existing process lines can be easily done as our ultrasonic extractors can be integrated without large modifications.
Our well-trained staff of process consultants, chemists, and engineers guide our customers towards a successful installation and operation. Hielscher‘s equipment has an outstanding robustness and requires only very low maintenance. For operational training, first commissioning, and maintenance service, we have a well-trained team which assist our customers.

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Cold brew tea is rapidly made by sonication. The UP400St extracts flavour and health-promoting compounds from the tea leaves within seconds without applying heat.

Ultrasonic Extraction of Tea - Hielscher Ultrasonics (Tea Cold Brewing)

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Dlaczego Hielscher Ultrasonics?

  • Superior quality
  • Made in Germany
  • obsługji 24-godżinniej
  • Heavy-duty approved
  • Simple installation and retro-fitting
  • Safe and easy operation
  • Easy to clean
  • niskie koszty utrzymania
  • Knowledge and consultancy
  • Customer Service

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During a decaffeination process, caffeine is removed from coffee beans, cocoa, tea leaves, or other caffeine-containing material. Decaffeinated beverages such as decaf coffee or tea are in increasing demand. The ultrasonically-assisted decaffeination process helps to produce high-quality, organic and healthy decaffeinated products. The avoidance of harsh chemicals is economical since the cost for solvents and their energy-intense recovery via evaporation is not longer necessary. The prepared decaffeinated product (coffee, tea, cocoa) is healthier, since on solvent-decaffeinated products traces of solvent can be found after solvent removal. This makes ultrasonically-assisted decaffeination ecologically and environmentally favourable.


High performance ultrasonics! Hielscher's product range covers the full spectrum from the compact lab ultrasonicator over bench-top units to full-industrial ultrasonic systems.

Hielscher Ultrasonics manufactures high-performance ultrasonic homogenizers from laboratorium to industrial size.

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