Moisture sensors for food processing in high-humidity environments

Author: T. Graf

In our previous article, we already described the requirements placed on humidity sensors in environments with consistently high humidity and why nearly saturated air poses a particular challenge for measurement technology (→ see article: High-Humidity AFTF 35 / KFTF 35).

But how do these conditions affect real-world operation?

The food industry is a particularly demanding sector. In processing and production areas, cleaning procedures, fluctuating temperatures, and high humidity often lead to condensation. This can compromise measurement accuracy and negatively impact process reliability, system stability, and product quality.

In this article, we show how such conditions in food processing can be reliably controlled and why specially designed humidity and temperature sensors are crucial for stable and efficient production processes.

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In a nutshell

In food processing, humidity is not just a convenience factor, but a key factor in process reliability, product quality, and plant operations. Cleaning cycles, wet areas, cold surfaces, and changing production phases often lead to high relative humidity and an increased risk of condensation.

Condensation-protected humidity and temperature sensors help reliably measure humidity and temperature—even during challenging periods of high humidity.

Typical benefits:

  • Stable readings at high relative humidity
  • better assessment of condensation risks
  • Support for Ventilation, Cooling, and Dehumidification
  • Suitable for production areas, wet areas, and air ducts
  • Easy integration into building management systems, DDC, or process automation

Contents

Why Humidity Measurement Is So Important in Production and Wet Areas Typical challenges: cleaning, moisture exposure, and temperature fluctuations What metrics are relevant in food processing? AFTF-35 or KFTF-35—which model is best suited for food processing? Installation and Measurement Points in Production Areas

Applications in Food Processing

In food processing, high humidity levels often occur in areas where cleaning, cooling, rinsing, production, or packaging take place. Environmental conditions can change rapidly, especially in production and wet areas: Humidity and temperature conditions during operation differ from those after cleaning, cooling, or downtime.

Typical applications include:

  • Production facilities with high ambient humidity
  • Wet Areas and Cleaning Zones
  • Cooling and Transition Zones
  • Packaging and Processing Areas
  • Ventilation and Air Conditioning Ducts in Production Facilities

For operators, this means that humidity measurement must function not only under stable, continuous operating conditions, but also under changing conditions. Only when humidity and temperature are reliably measured can ventilation, cooling, and dehumidification be properly controlled.

Why Humidity Measurement Is So Important in Production and Wet Areas

In food processing facilities, relative humidity affects several areas simultaneously: product quality, hygiene conditions, equipment availability, and energy efficiency. High humidity can promote condensation on cold surfaces, pipes, ceilings, walls, or equipment components. This is not only a measurement issue but can also affect the production process.

If humidity is not reliably measured, the control system may react too late or respond to inaccurate readings. This can result in unnecessary ventilation or dehumidification cycles, unstable indoor conditions, or unclear causes of humidity problems.

Reliable humidity and temperature measurements help identify critical conditions early on and control the indoor or process air more effectively.

Typical challenges: cleaning, moisture exposure, and temperature fluctuations

In food processing, the most challenging conditions often arise not during steady-state production, but during fluctuating operating conditions.

Typical influencing factors include:

  • Wet cleaning: After cleaning cycles, the humidity level in the room often rises significantly.
  • Temperature changes: Cold surfaces and warm, humid air increase the risk of condensation.
  • Production and Downtime Phases: When switching between operation, cleaning, and downtime, humidity and temperature often change rapidly.
  • Ventilation and Airflow: Supply and exhaust air, recirculation systems, and dehumidification affect local humidity distribution.
  • Spray mist and wet surfaces: Localized moisture spikes can affect measurement readings if the measurement point is chosen poorly.

Conventional humidity sensors can reach their limits in such situations. If condensation forms on the sensor element, this often results in sluggish readings, longer recovery times, or inaccurate control signals. Condensation-protected humidity and temperature sensors reduce this risk and help ensure more stable readings during critical periods of high humidity.

What metrics are relevant in food processing?

When it comes to climate control in production and wet areas, it is not just individual measurement values that are crucial, but how they interact. Temperature fluctuations and high humidity levels, in particular, can cause the relative humidity to change rapidly.

Key metrics include:

  • Relative humidity—a key control variable for indoor and process air
  • Temperature – directly affects how much moisture the air can hold
  • Dew Point – Helps Assess Condensation Risks
  • Absolute humidity – indicates the actual water content of the air
  • Mixing Ratio – Helps Evaluate Ventilation and Dehumidification Processes

The AFTF-35 and KFTF-35 measure humidity and temperature and can provide additional calculated parameters for building management systems (BMS), distributed control systems (DCS), programmable logic controllers (PLCs), or process automation.

AFTF-35 or KFTF-35—which model is best suited for food processing?

Depending on the system, both surface-mounted sensors and duct sensors can be used in food processing. The key factor is where the measured value is needed for control purposes.

AFTF-35 as a surface-mounted sensor

  • Wall mounting in production, technical, or auxiliary areas
  • Direct measurement of indoor air
  • Suitable for areas with high humidity and dynamic operating conditions

The AFTF-35 is suitable for situations where humidity and temperature need to be measured directly in the room—for example, in production areas, packaging zones, or technical utility rooms.

KFTF-35 as a duct sensor

  • Installation in ventilation and air conditioning ducts
  • Measurements in Supply or Exhaust Air Ducts
  • Suitable for HVAC systems, recirculating air systems, and central air handling systems

The KFTF-35 is useful when humidity and temperature need to be measured in the air ductwork, for example, to control supply and exhaust air, dehumidification, or central air conditioning.

In larger facilities, it may be useful to combine both measurement points: The duct sensor indicates which air is being supplied or exhausted. The room sensor indicates the actual conditions in the production area.

Installation and Measurement Points in Production Areas

The measurement location should be chosen so that it captures the actual room or process conditions as accurately as possible. For the AFTF-35, we recommend a readily accessible location with sufficient air movement—not directly next to doors, not immediately in the airflow from vents or fans, and not in areas heavily affected by spray water, cleaning, or local humidity spikes.

The KFTF-35 is installed as a duct sensor in ventilation or air-conditioning ducts using the mounting flange provided. Before installation, ensure that the measurement range, installation length, duct dimensions, flow velocity, and protection class are suitable for the application.

Important: The AFTF-35 and KFTF-35 are designed for high-humidity environments, but are intended only for use with non-polluted, non-condensing air and without positive or negative pressure at the sensor element. Installation and commissioning must be performed only by qualified personnel. For specific installation, always follow the instructions in the operating and installation manual.

Select the right humidity sensors for food processing now

In food processing, high humidity, cleaning processes, temperature fluctuations, and changing production phases place special demands on measurement technology. The AFTF-35 and KFTF-35 are designed for such high-humidity applications and provide stable measurements of humidity, temperature, and additional humidity parameters.

For you, this means:

  • reliable measurements during critical high-humidity phases
  • a better foundation for ventilation, cooling, and dehumidification
  • Easy integration into building management systems (GLT), DDC, PLCs, or process automation
  • Greater certainty in assessing condensation risks
  • Support for stable production and environmental conditions

Depending on the installation situation, choose the appropriate model: AFTF-35 for direct ambient air measurement or KFTF-35 for installation in ventilation and HVAC ducts.

Discover sensors for high humidity in food processing now

Bestseller AFTF-35 / KFTF-35

HYGRASGARD® AFTF-35-I/W
°C
%RH

On-wall humidity and temperature sensors

HYGRASGARD® AFTF-35-I/W

790,69 €
790,69 €
HYGRASGARD® AFTF-35-U/W
°C
%RH

On-wall humidity and temperature sensors

HYGRASGARD® AFTF-35-U/W

790,69 €
790,69 €
HYGRASGARD® KFTF-35-U/W LCD
°C
%RH

Duct humidity and temperature sensor

HYGRASGARD® KFTF-35-U/W LCD

903,63 €
903,63 €
HYGRASGARD® KFTF-35-U/W
°C
%RH

Duct humidity and temperature sensor

HYGRASGARD® KFTF-35-U/W

790,69 €
790,69 €
HYGRASGARD® KFTF-35-I/W LCD
°C
%RH

Duct humidity and temperature sensor

HYGRASGARD® KFTF-35-I/W LCD

903,63 €
903,63 €
HYGRASGARD® KFTF-35-I/W
°C
%RH

Duct humidity and temperature sensors

HYGRASGARD® KFTF-35-I/W

790,69 €
790,69 €
HYGRASGARD® AFTF-35-U/W LCD
°C
%RH

On-wall humidity and temperature sensors

HYGRASGARD® AFTF-35-U/W LCD

903,63 €
903,63 €
HYGRASGARD® AFTF-35-I/W LCD
°C
%RH

On-wall humidity and temperature sensors

HYGRASGARD® AFTF-35-I/W LCD

903,63 €
903,63 €

FAQ

Which moisture sensors are suitable for food processing?

Condensation-protected humidity and temperature sensors, such as the AFTF-35 and KFTF-35, are suitable for production areas, wet areas, and ventilation systems with high humidity.

Why is humidity measurement challenging in wet areas?

Cleaning, spray mist, cold surfaces, and temperature fluctuations can lead to spikes in humidity and an increased risk of condensation. This places greater demands on the sensors and the measurement point.

When is the AFTF-35 a good choice?

The AFTF-35 is suitable for direct ambient air measurement in production, technical, or auxiliary areas.

When is the KFTF-35 a good choice?

The KFTF-35 is suitable for installation in ventilation and air-conditioning ducts, for example, for measurements in supply or exhaust air ducts.