Food dehydrators were once found just in the homes of hunters and gardeners who sought to extend the shelf life of abundant fresh food, but dehydrators now are becoming more popular.

The virtues of these drying machines are many, particularly for people who keep close tabs on where their food comes from. Dehydrators let gardeners easily preserve peak-of-season herbs, fruits and vegetables for later use, and snacks like fruit roll-ups and jerky can be made cheaper and more flavorful than store-bought versions. Pet treats are easy to make in dehydrators too.

Many models are compact enough to sit on a countertop, making them useful for the most space-compromised apartment dweller. More efficient than ovens, the dehydrators can dry a lot of food at one time and do so quicker while locking in nutrients.

I tested four popular food dehydrators to see how easy they were to use. I tested drying herbs, mushrooms, citrus fruits, cherry tomatoes, peppers, bananas and beef jerky. How long it takes to desiccate certain foods depends on the thickness of the item, but, generally, herbs and mushrooms dried in one to three hours, jerky took about four to five hours, while more water-dense fruits and vegetables took up to 12 hours.

All models but the Excalibur have stackable trays. The Excalibur has sliding shelves.

Oster 4-Tray Electric Food Dehydrator

This was the most basic model tested, with just an on/off switch and four trays. Dryer is in the base. An entry-level machine, this is best for occasional use. Did fine with jerky, mushrooms and pepper slices, but citrus, tomatoes and bananas were a bit tricky, as they would sometimes "case harden," meaning the outside would be dry, but the inside was still soft, perhaps because there was no way to adjust the temperature. Temperatures were a bit too high for drying delicate or aromatic herbs. The lack of a screen means small items like thyme leaves had to be left on the stem. Loudest model tested, but noise level was not an issue. $50 at amazon.com

Waring Pro Food Dehydrator

This model had the smallest footprint of all four models; good for small kitchens. Its five trays held about the same amount of food as the four-tray Oster, but less than the five-tray Nesco model. Dryer is in the base. Has four temperature settings (fan, low, medium, high), which made it easier to dry delicate items like herbs. I used the supplied fruit roll-up sheet for small leaves to avoid having them fall into the base. Uniform drying. Did fine on all products tested, but generally took a bit longer to dry than other machines with temperature controls. Additional stackable trays available for purchase to expand footage. Quiet operation. $69.95 at waringpro.com

Nesco Snackmaster Pro Food Dehydrator

Nesco makes several models. I tried the five-tray Snackmaster Pro model. It has the fan at the top versus the base, which prevents food from falling into the dryer and makes it easier to clean. It was speedier than the Waring model and offered more uniform drying than the Oster. It did fine with all products tested. Benefits to this model were seven precise temperature settings (95 to 160 degrees Fahrenheit), with temperature suggestions for different products on the cover. One downside is there is no on/off switch, so I had to unplug it to stop the machine. Came with two jerky seasonings/cures, two fruit roll-up sheets, two small-item screens and a detailed dehydrating guide. Additional stackable trays available for purchase to expand footage. Quiet operation. $69.99 at nesco.com

Excalibur 5-Tray Food Dehydrator

Excalibur makes several models; I tested the five-tray with a 26-hour timer. This was the biggest of the four tested. It just fit on my countertop, but I used a small tray table to hold it. Because of its larger size, it held the most food, and its boxlike frame construction had the dryer in the back, which prevents accidental contact with food. Like the Nesco, it had a dial with precise temperature settings (105 to 165 degrees Fahrenheit) and suggested levels for various products on the machine, drying at the same rate. Drying was uniform and fine on all products. The timer was a nice addition. Because it has a frame with removable trays, you can use it for other purposes, such as making yogurt or raising bread. Comes with a detailed dehydrating guide. $249.95 at excaliburdehydrator.com