Journey to the end of humidity


When it comes to smoking, humidity plays a decisive role. But depending on the product, depending on the system, depending on the recipe, the humidity has towork differently.

Meat is a natural product. From pork to salami or from beef to cider crumbs, it is a complex process with many different steps. In this article, we have  written a reference work for humidity:

How humidity works in a (smoking) system and what different methods there are for moisture regulation.


Humidity measurement with two probes

Humidity measurement electric


Dehumidifying with flaps

Dehumidifying with cooling

Dehumidifying with pause

pH value-controlled dehumidification

Cooking – baking with dehumidification


Cooking and humidity

Climate with humidity spreading

Humidity curve during smoking: open

Moisture curve during smoking: closed

Humidity measurement with two probes

The measurement of humidity in a smoking plant is carried out with the help of a humidity measuring point, which works according to the principle of psychrometry. This site typically has two temperature sensors. One probe in the dry (room temperature) and one in the wet, with a damp flap hanging in the water.

Psychrometric measuring point

Due to the air flow that sweeps over the measuring point (at least 2m/s), the water evaporates at the humidity sensor. As a result, the humidity sensor measures a lower value than the dry sensor, depending on the moisture content of the air. Due to  the temperature difference  between the humidity and the dry sensor, the relative humidity can be calculated using a proportional formula. This calculation makes the controller automatically.

If the system is poorly calibrated, an error of even 1°C can result in a deviation of up to 7% relative humidity.

Molton rags

Humidity measurement electric

In a room without tar (without smoke generators), the humidity can also be calculated electrically. A small box is installed in the chamber and this sends the relative humidity back to the controller as an electrical signal. The controller then no longer has to calculate anything itself – the calibration has already been done in advance. There is no need to top up with water or change damp cloths.

Electronic temperatureand humidity sensor


Drying is the most classic of all steps. Flaps for fresh air and exhaust air are open, air is sucked into the chamber. The air goes around the product and absorbs the moisture. And then the air is removed again by the exhaust air. The product becomes steadily drier.

Dehumidification with flaps

If the product is too dry, it can seal and release moisture with difficulty. For this reason, a minimum humidity can be set during a drying step. For example, 40%. If the humidity drops below 40% - then the fresh air and exhaust air flap close. The product does not get new, dry air and can release moisture on its own. The humidity automatically rises again until the selected humidity value is exceeded, then the flaps open again. In this way, the moisture can be optimally removed.

Dehumidification with cooling

In the cold smoke area, the moisture can also be removed with cooling. The moisture does not escape via the fresh and exhaust air flaps, but circulates between the cooling and heating coils and the chamber. If the humidity is too high, the cooling is switched on. Warm air condenses as it passes through the cooling system, and the water drains off underneath the cooling system. The product loses moisture – and weight.

Dehumidification with pause

A product that is constantly treated with air can seal its surface and be dry on the outside and still quite fleshy on the inside. If there is no possibility of precise moisture measurement,  drying + pause in the interval can also be used to dry down to the core of the product. You dry the goods and then take a break. During the break there is no heating, no circulating air and no cooling. The flaps are closed. During the break, the product recovers and the moisture is carried from the inside to the outside.

pH-controlled dehumidification

Especially in the production of salami, the pH value plays an important role. Salami must first be sweated before it is dried in the climate step. Only when the  pH value has reached its isoelectric point of approx. 5.3 to 5.2 pH is dehumidification optimal. The pH sensor can be plugged into the product. This process first requires sweating the product to lower the pH and allow moisture to be released.

pH electrode

Cooking - Baking with dehumidification

If, for example, meat loaf is baked in the system, all flaps are closed. The product itself loses water – which turns into steam at high temperatures. Due to the increasing humidity, the process changes from baking to cooking. To prevent this from happening, the exhaust air flap must open at regular intervals during cooking so that the accumulated moisture escapes and the popular crust can form.


There are also variants of adding moisture to the system – which should not come from the product. Moisture control can be done in a number of ways. One option is to artificially humidify the air in the system, for example by injecting water. As described in "Dehumidification with flaps", the natural moisture of the product can also be used to increase the humidity in the system.

Cooking and humidity

If you want to cook your product, you need moisture. The higher the humidity in a chamber, the better the temperature transfer. Moisture is usually added over a cycle – until the desired, set humidity has been reached. Cooking usually has a relative humidity of over 90%. If there is no moisture, the product (boiled sausage) tends to become "shriveled".

Climate with humidity spread

Climate processes are defined with a humidity band.

For example, the relative humidity must be 72% +3% and -6%.

This means that the system only humidifies or dehumidifies when the humidity rises below 66% or above 75%. Within the set moisture band, the product has time to build up moisture and then remove it again.

Humidity tapecontrolled process with the EB1 controller

Moisture profile during smoking: open

In an open system, the fresh air damper is slightly open during a smoke step. The new air dries the product further – it is important that the humidity is not too low when the smoking process starts. Because then it may be that the smoke is no longer absorbed by the dry intestine.

Humidity curve during smoking: closed

In a closed system, the humidity increases steadily during the smoking process. The smoke is moist and since there is no fresh air, the intestine absorbs the moisture and becomes smoke-permeable. The smoke gets under the skin and creates a smoke rim. It is important that the product is evenly dried before the smoke step.

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