Horizontal vs vertical airflow dehydrators

How air moves in each design

In a horizontal airflow dehydrator, the fan and heater sit at the back of a box. Warm air blows forward across each tray side by side, so every shelf gets air at roughly the same temperature at the same time. The Excalibur listing calls this Horizontal Parallex Air Flow, the Cosori listing describes a rear fan, and the LEM BigBite 16-tray in our catalog lists dual rear-mounted fans with rear venting.

In a vertical airflow dehydrator, round trays stack on a base, and the fan and heater sit in the base or the lid. Air travels up or down through the stack, passing over one tray before reaching the next. Classic stackable units often need trays swapped partway through so the ones farthest from the fan catch up. Some makers address this with ducted designs: the NESCO FD-1018A listing describes a top-mounted fan with a Converga-Flow system that it says dries evenly without tray rotation.

Three dehydrators side by side

Evenness and tray rotation

Because every tray in a box unit gets air straight from the rear fan, horizontal designs are generally the more even of the two. Food near the back of each tray can still dry a little faster than food at the front, so turning trays front to back once during a long run is a cheap habit that helps any box unit.

Vertical units vary more by model. A basic stackable dehydrator with the fan in the base can leave top trays wetter than bottom ones. Better designs such as the NESCO with its top fan and ducted airflow aim to reduce this. With any stackable unit, check pieces from the top, middle and bottom trays before you call a batch done. Our dehydrator drying unevenly page lists the causes and fixes for both types.

Flavor mixing, capacity and tall items

Flavor mixing. Strong smells such as onions, garlic and jerky marinades travel with the air. In a vertical unit the air passes from tray to tray, so drying onions under apples is a reliable way to get onion-flavored apples. A box unit shares air within one cabinet too, but because air crosses each tray separately before exhausting, mixing tends to be less pronounced. In either type, dry strong foods in their own batch.

Capacity. Box units have a fixed number of trays. The Excalibur and Cosori both list 10 trays and about 16 sq ft. Stackable units can grow: the NESCO listing says it expands from 8 to 30 trays, though more trays means more distance from the fan.

Tall items. In a box you can slide out trays to make room for jars of yogurt, bread proofing or thick items. Stackable trays sit at a fixed spacing unless you buy extra rings or spacers.

Price, materials and safety

Stackable round dehydrators are usually the cheaper way in; the NESCO is listed at $176.99 against $269.99 and $379.99 for the two box units. Box units in our catalog commonly come with stainless steel trays, while many stackable units use BPA-free plastic trays, as the NESCO does.

For jerky, temperature matters more than airflow direction. USDA advises heating meat to 160 F and poultry to 165 F before drying, then drying at a steady temperature. All three units list a maximum of 160 to 165 F. See how to make jerky in a dehydrator and the dehydrator temperature chart.

Note.Home dried jerky keeps about 1 to 2 months at room temperature according to USDA FSIS. Most home dried fruits keep about 1 year at 60 F per NCHFP. Store dried foods airtight, cool and dark.

See the best dehydrators for jerky →

Which design to buy

For the wider field, see the best food dehydrators and the best Excalibur dehydrators. Still weighing other machines? Read food dehydrator vs air fryer or freeze dryer vs dehydrator.

• Buy horizontal if you dry jerky often, run mixed loads, want stainless trays, or need room for tall items.
• Buy vertical if you want the lowest price, expandable capacity, or a lighter unit you can store away.
• Buy a large horizontal unit for big batches; see the best commercial dehydrators.

Frequently asked questions

Do I need to rotate trays in a horizontal dehydrator? Usually not between shelves, and the Excalibur listing says no rotation is needed. Turning trays front to back once on long runs can still help.

Why is the top tray of my stackable dehydrator still wet? It is farthest from a base-mounted fan, or the stack is too tall. Swap trays partway through or dry fewer trays at once.

Can I dry onions and fruit together? It is best not to in either type, and especially not in a stackable unit where air passes through every tray.

Why is my dried fruit still sticky? It usually needs more time or thinner slices. See dehydrated fruit still sticky.