A food dehydrator is a simple machine that dries food to preserve it for later use.
The food dehydrator trays are the platforms in which the warmed air passes over to accomplish the task at hand.
Trays and machines come in two sub groups: round and square or rectangle and air passage by vertical or horizontal movement.
That is the sum total.
One other consideration is the construction of the unit itself.
This is normally plastic, but stainless steel is an option.
Also, the round units tend to be less expensive.
This does not mean that they are cheaper, therefore poorer quality.
Round: These are the ones seen almost everywhere from big box stores to the local hardware store.
These are the entry level machines, great to get started with.
The trays are less productive as the layout of foods to dry sometimes does not match up well with the round tray.
An American harvest food dehydrator FD1010 is a perfect example of this type of unit.
Square or Rectangle:? This type of tray increases the efficiency of the home food dehydrator.
When making a product like food dehydrator jerky, square corners are best.
An example of this type is an L equip food dehydrator FilterPro.
Air Circulation Vertical: This can be critical to a quality result.
Vertical air flow has a tendency to mix aromas and flavors in the unit.
By doing one type of drying at a time, like apple or then cherries or a load of jerky will work just fine.
However, I would not mix different items to be dried at one time.
Air Circulation Horizontal: This style of dehydrator trays drys ultimately the best.
Load different products and the horizontal air flow will do the trick.
An Excalibur 9 tray food dehydrator is the absolute best example for this type of unit.
Ask Santa for your dehydrator now, do not wait till Christmas! Happy drying and happy nutrition, Mary Dahlberg