by Dave Schwaller, Senior Manager, Engineering Applications, DriSteem
When people discuss pharmaceutical and biotechnology manufacturing, conversations often focus on formulation, equipment, automation, validation, and quality systems. Yet there is another factor that routinely shows up in investigations of unexpected variability, material handling problems, and environmental deviations: humidity.
Manufacturers often think of humidity as an environmental parameter, but in many pharmaceutical and biotech facilities it functions more like a process variable. When humidity changes, materials behave differently, processes respond differently, and product quality can be affected. Humidity can influence process stability, material handling, equipment performance, regulatory compliance, and ultimately the consistency of the finished product.
Maintaining the appropriate humidity level is often essential to achieving repeatable results from batch to batch. The challenge is that the consequences of poor humidity control are not always immediately obvious, making it easy to underestimate its impact on production performance.
Humidity and product consistency
One of the primary goals of pharmaceutical and biotech manufacturing is product consistency. Whether producing tablets, capsules, biologics, vaccines, diagnostic products, or specialty therapeutics, manufacturers strive to minimize variability and deliver repeatable outcomes. The ability to maintain tight humidity tolerances often plays a larger role in production performance than many people realize.
Many pharmaceutical ingredients are hygroscopic, meaning they readily absorb moisture from the surrounding environment. Changes in humidity can alter material properties, affecting flowability, compressibility, particle size distribution, and processing behaviour. In some cases, moisture uptake can influence chemical stability, product appearance, or shelf life.
Powder handling operations provide a common example. Materials that perform well under controlled conditions may become difficult to process when humidity drifts outside established limits. Excess moisture can contribute to clumping, sticking, inconsistent flow, or product variability. Conversely, excessively dry conditions can increase static electricity, creating challenges during conveying, handling, filling, and packaging operations.
When humidity remains stable, materials tend to behave more predictably. Process parameters remain more consistent, operators spend less time making adjustments, and manufacturers gain greater confidence in production outcomes.
Reducing batch variability and waste
Manufacturing efficiency depends on controlling the variables that affect production. When humidity fluctuates significantly, process performance can become less predictable. Production teams may experience changes in product characteristics, yield losses, increased reject rates, rework requirements, or unexpected process interruptions.
Humidity is rarely the first place people look when these problems occur. Investigations often begin with equipment, raw materials, formulations, operating procedures, or operator techniques. Only later does the investigation reveal that changing environmental conditions contributed to the problem.
Over the years, one lesson has emerged repeatedly across pharmaceutical and biotech applications: consistent environmental conditions help support consistent manufacturing outcomes.
Facilities that maintain tight humidity tolerances often experience fewer environmental surprises during manufacturing. Materials enter the process in a more predictable condition, equipment operates in a more stable manner, and quality teams spend less time investigating unexplained variability.
The result is reduced waste, improved yields, and more reliable production performance.
Supporting Good Manufacturing Practice
Good Manufacturing Practice (GMP) is fundamentally about consistency and control. Manufacturers establish validated operating ranges because environmental conditions can directly affect both process performance and product quality. Facilities that maintain stable humidity levels are generally better positioned to operate within validated parameters, document environmental control, and support reproducible manufacturing outcomes.
Auditors and regulators are typically less concerned with the humidifier itself than with evidence that environmental conditions remain within established limits. This distinction is important. Successful humidity control is not about installing equipment. It is about maintaining reliable performance over time.
Where humidity has the greatest impact
One of the most common mistakes is assuming the same humidity strategy will work everywhere. Different products, materials, and manufacturing processes have different environmental requirements. Areas used for raw material storage, blending, granulation, tableting, coating, packaging, filling, laboratory testing, and biologics production may each require unique humidity strategies.
The challenge becomes even greater when multiple products or manufacturing processes share the same facility. A single humidity target for an entire facility is rarely the answer. Successful facilities evaluate the specific needs of individual spaces and processes, then design environmental control strategies around those requirements.
What we have learned across pharmaceutical and biotech applications is that understanding the process is often more important than selecting a particular humidification technology. The most successful projects start by defining process requirements and environmental objectives, then selecting humidity-control strategies that support those goals.
Looking beyond the humidifier
Long-term success never comes down to the humidifier alone. In most cases, humidity performance reflects the quality of the overall system more than the capability of a single piece of equipment. Water quality, controls, sensor placement, HVAC design, maintenance practices, operating schedules, and production requirements all influence results. When humidity-related issues occur, the root cause is often found in one of these areas rather than in the humidification equipment itself.
Water quality deserves particular attention. Minerals and impurities can affect efficiency, maintenance requirements, equipment life, and operating costs. Evaluating local water conditions early in a project is a good way to avoid operational challenges later.
Controls are equally important. Manufacturing loads, occupancy patterns, ventilation rates, and process conditions change continuously. Sensors must provide accurate readings, and control strategies must respond appropriately to changing conditions in order to maintain tight tolerances.
Experience shows that achieving consistent humidity control requires a systems approach rather than an equipment-focused approach.
The value of application expertise
DriSteem humidification systems, for example, are installed in pharmaceutical, biotechnology and life science facilities worldwide. Across those facilities, the same pattern appears repeatedly: the projects that perform best over the long-term treat humidity as part of the manufacturing process rather than as a stand-alone HVAC function.
The most successful projects begin with a detailed understanding of production requirements, environmental objectives, water quality conditions, maintenance expectations, and operational priorities. Design decisions made in the beginning will influence performance for decades.
This is particularly important as facilities pursue greater efficiency, increased production capacity, and more demanding quality expectations. Systems that consume excessive resources, require frequent intervention, or struggle to maintain target conditions can create ongoing operational headaches.
By contrast, well-designed humidity control systems maintain target conditions reliably, allowing production teams to focus on product quality and manufacturing performance rather than environmental issues.
Humidity as a performance metric
As manufacturing processes become increasingly sophisticated and quality expectations continue to grow, precise humidity control will remain an important part of achieving repeatable outcomes and batch-to-batch consistency.
Facilities that understand how humidity influences both process performance and product quality will be best positioned to reduce variability, minimize waste, support compliance efforts, and maintain reliable production performance over the long-term. Time and again, that understanding proves just as important as the equipment itself.