Everyone has already asked the question: "How does a dehydrator work" or "What makes a dehydrator". To answer this question, we will have a closer look to 2 dehydrator, the Rosenstein and Söhne and the Excalibur 9 trays with timer, detailing all their elements.

The overall shape

The majority of dryers are:

• eighter shaped as a rectangular box like the Excalibur: trays are sliding drawers and because of the box, the number of tray is fixed and cannot be expanded.
• eigther round with a trays stack like the Rosenstein and Söhne. It consists of a base that contains the electronics (power supply, fan and heater), the trays and a lid.

Trays

Their shape follows the general shape of the dehydrator. Excalibur trays are square and slide into the cage. Trays are most often plastic but for example Stöckli propose metal trays which have a smaller mesh perfect for drying herbs.

The heater and the fan

The primary purpose of a food dryer is to blow hot air over the trays and the fruit pieces. The hot air is heated by an electronic resistance and then blown by a fan.

In most electric dryer, the heater is only a wire shaped like a spring. The wire gets hot when powered and heats the air around it. Dehydrators can have a thermostat like the Excalibur which can adjust the drying temperature by adjusting the current flow in the wire.

To increase the efficiency of hot air, a fan is used to blow that air. Excalibur models have a big enough fan to be considered as ventilated dryers. On the other side cheap models such the Rosenstein & Söhne have only a small fan which is not optimal.

Settings

All dryers have at least a On/Off button. The more advanced models have either a thermostat, a timer or both.  The thermostat controls the drying temperature. Models without a thermostat have a fixed temperature.

Timer is usefull to stop the dryer after some hours.

Additional photos

Excalibur:

Rosenstein & Söhne: