Stability Freezers

The Darwin Chambers Stability Freezers are designed for performance specifications exceeding FDA and ICH requirements. Thousands of our stability freezers are presently in use by many pharmaceutical, cosmetic, nutraceutical, medical device, therapeutic pharmaceuticals, pharmaceutical stress testing, and other research companies around the world. The Darwin Chambers Stability Freezer FS Series is a top selling stability freezer chamber very common in laboratories.



The FS011 is a bench top stability freezer chamber. Units can be stacked with optional racking set-up.



The FS030 is a single-door stability freezer chamber.



The FS034 is a single-door stability freezer providing extra cubic feet designed for maximum capacity while still allowing passage through most comm …



The FS055 is a two-door stability freezer chamber.



The FS084 is a three-door stability freezer chamber.

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FS Series Features

FS Series

The FS Series is a top selling stability freezer chamber very common in laboratories.

Widely Proven, Non-Proprietary Controllers

Standard controllers for the FS Series are manufactured by Fuji Electric and are ideal for laboratory freezer. Unlike many proprietary controllers, this controller is commercially available and proven in tens of thousands of installations. Standard functions include: autotuning, fuzzy logic, PID control, programmable alarms, calibration capability, ramp/soak, offset capability, etc. A touchscreen control interface is optional. Other controller manufacturers are also supported (Watlow, Allen-Bradley etc.)

Refrigeration System

The FS Series provides an oversized and balanced, environmentally friendly R404A refrigeration system with an epoxy-coated evaporator coil. This large evaporator and coil heater allow for a short defrost cycle, along with an automatic evaporator fan motor to delay frost formation during defrost.

Temperature Range

The FS series offers a temperature range of -25º C to +15º C.

Services and Warranties

We offer technical support throughout the lifetime of your freezer. In addition to standard warranties, we also offer extended warranties for cooling components, parts and labor. We also provide qualifications, validations and preventive maintenance services at an additional cost. Please ask for a quote.

Options Available

Chart Recorder
Data Logger

Frequently Asked Questions (FAQs) About Stability Freezers

What is the Best Reason For Having a Stability Freezer?

The best reason for having a stability freezer is the ability to ensure the long-term preservation and stability of sensitive materials – especially those used in research, biotechnology, and pharmaceuticals. Stability freezers are specifically designed to maintain consistent temperature and humidity conditions over extended periods – commonly ranging from months to years.

What is Typically Kept in Stability Freezers?

Stability freezers are used to store a variety of temperature-sensitive materials, especially those that require precise temperature control, uniformity, and stability over extended periods. Some items that are commonly kept in stability freezers include:

  • Pharmaceuticals – Pharmaceutical materials require controlled temperature conditions to assess their long-term stability, degradation kinetics, and shelf-life under various storage conditions.
  • Biological Samples – These can include cell lines, tissues, enzymes, proteins, and nucleic acids.
  • Vaccines & Biologics – These temperature-sensitive products must be stored in stability freezers to maintain their potency, efficacy, and safety throughout their shelf life.
  • Chemical Reagents – These include any buffers, standards, solvents, and biochemicals that require temperature-controlled environments.
  • Clinical Samples – These could include patient samples, such as blood, urine, plasma, serum, and tissue specimens, for diagnostic testing, biomarker analysis, and medical research.
  • Reference Materials – These materials may include certified reference materials, proficiency testing samples, and internal quality control specimens used in laboratory accreditation and quality assurance programs.

What is the Difference Between a Stability Freezer and a Regular Freezer?

The primary difference between a stability freezer and a regular freezer lies in their design, temperature control capabilities, and intended use. The following are some key distinctions:

  • Temperature Control Precision: Stability freezers are specially engineered for precise and stable temperature control over a wide range – normally from -20°C to -80°C or even lower. They use advanced temperature regulation systems – like microprocessor-based controllers, dual cooling systems, and high-performance insulation – to maintain tight control. Regular freezers, such as household or commercial units, have less precise temperature control and may experience frequent temperature fluctuations, especially when doors are opened or during defrost cycles.
  • Construction & Insulation: Stability freezers have robust construction and insulation to minimize heat transfer and temperature fluctuations. They frequently incorporate heavy-duty insulation materials, like high-density foam or vacuum panels, and have reinforced doors and gaskets to prevent temperature leakage. In contrast, regular freezers tend to have thinner insulation and are not optimized for long-term stability or precise temperature control.
  • Uniformity & Stability: Stability freezers are built to maintain consistent temperature and humidity conditions throughout the entire storage chamber, ensuring uniformity across all stored samples. Regular freezers typically have far less uniform temperature distribution, leading to gradients within the storage space, which can affect sample integrity and stability.
  • Cost & Performance: Stability freezers are normally more expensive than regular freezers due to their specialized design, top-tier temperature control systems, and compliance features. However, they offer superior performance and reliability for applications that demand precise temperature control, uniformity, and stability over extended periods.

What are the Benefits of Stability Freezers?

Stability freezers are essential for ensuring the integrity, quality, and stability of sensitive materials in various industries. Utilizing precise temperature and humidity control, these storage units help researchers and companies maintain the reliability of their research/experiments, protect their investments, and comply with regulatory requirements. Additionally, stability freezers have the following advantages:

  • Research & Development: Stability freezers play a crucial role in preserving valuable samples and materials used in research laboratory studies and scientific research. The freezers provide researchers with confidence in the stability and reliability of their materials, whether that consists of cell lines, enzymes, or antibodies.
  • Preservation of Samples: Stability freezers provide a controlled environment with precise temperature and humidity settings, ensuring the preservation of delicate samples, including pharmaceutical products, chemicals, biological materials, and reagents.
  • Quality Control & Assurance: Stability testing is vital for assessing the quality, efficacy, and shelf life of pharmaceuticals, biologics, and other products. Stability freezers enable manufacturers to conduct accelerated aging studies, real-time stability testing, and long-term studies to evaluate product stability under various environmental conditions.
  • Cost Savings: Preventing the degradation or loss of valuable materials due to poor storage conditions can save companies substantial costs associated with recalls, retesting, and replacement. Stability freezers help minimize the risk of financial losses, product failures, and regulatory noncompliance by keeping suitable storage conditions and ensuring sample stability over time.