Metrolab Blog

Introduction to Freeze Drying (Lyophilization) by Martin Christ

Freeze-drying, or lyophilization, is the gentlest method for drying materials. The underlying physical phenomenon of sublimation refers to the direct transition from a solid to a vapor state, bypassing the liquid state. The frozen product is thus dried under vacuum without thawing out. The method has a wide range of potential applications:

  • Maintaining product characteristics of the original substances (e.g., pharmaceutical products, milk)
  • Preserving the initial shape (e.g., taxidermy, archeological objects, flowers)
  • Conditioning the material (e.g., freeze-dried fruits)
  • Chemical analysis, sample preparation (e.g., trace organic testing in food products, sludge, and soils)

Freeze-drying is used for over 30 different categories of substances and materials, with the most important markets being the pharmaceutical and biotechnology fields, sample preparation in labs, and stabilizing food products.
In general, freeze-drying is divided into discontinuously and continuously operated systems. Discontinuously operated systems are available on the market in versions from 2 kg to about 1 metric ton per batch.
Martin Christ has focused on this product group and is the only manufacturer worldwide of both series-production lab units and pilot freeze-dryers, up to large production lines.

Laboratory freeze-drying systems

  • Ice condenser capacity from 2 to 24 kg
  • Air-cooled chilling systems
  • Wide range of accessories for a variety of applications
  • Typically for drying pre-frozen products

Pilot freeze-drying systems

  • Ice condenser capacity from 4 to 16 kg
  • air- or water-cooled refrigeration systems
  • Freezing and drying in the drying chamber on liquid-cooled shelves
  • Insulator integration is possible

Production freeze-drying systems

  • Ice condenser capacity from 20 to 500 kg
  • Water-cooled chilling systems
  • Freezing and drying in the drying chamber on liquid-cooled shelves
  • Single or dual chamber systems
  • Special customer-specific systems, with cleaning and sterilization
  • Process integration with automated loading and unloading (LyoShuttle) and insulator integration

Find more information about fundamentals, process management, and applications of freeze-drying here.