DIY: Hops Dryer

Ovens and dehydrators can be too aggressive when it comes to drying hops. You can easily build your own drying rack instead, and we’ll show you how!

Jester Goldman Sep 30, 2016 - 8 min read

DIY: Hops Dryer Primary Image

Brewing with homegrown hops is as satisfying as cooking with food from your own garden. But while zucchini and tomatoes can go straight from harvest to kitchen, hops need to take a quick detour to be dried first. It’s true that you can skip the drying process if you’re making a wet-hopped beer, but once your hops take off and you have a big crop, you’ll likely surpass what you can use in a short time.

Fresh hops start out with a water content of about 80 percent, and your target is about 8–10 percent. The key is to remember that hops are literally a delicate flower. If you treat them roughly, they’ll suffer. You have to dry them out fairly quickly to minimize the impact of heat, light, and oxygen. You also need to be careful not to overdry them.

Several Approaches

Many people automatically think of using their oven to dry hops. The problem is that the lowest setting is likely 150°–170°F (65–77°C), and it’s important to keep the temperature below 140°F (60°C), with 100°F (38°C) being even better. If you leave the oven open and you’re careful to turn the hops regularly, this can work…but I don’t recommend it.

A better choice is to use a food dehydrator, but temperature can be an issue here, too. If your dehydrator doesn’t have a low enough setting to get into the right range, then you have to worry about driving off volatiles from your hops.


It’s best to rely on warm ambient temperature and airflow to do the job. You could just spread the hops on a screen and blow air across them, but that doesn’t scale well. Another low-effort option is to create a multi-tier sandwich of furnace air filters, with thin layers of hops as the filling. You can bungee and tape the whole collection—up to five layers—together and place it against a fan to drive the moisture off. If you go this route, remember to orient all the filters in the same direction for airflow, with the fan blowing into the intake side (air filters are usually labeled clearly).

With a little more work, you can scale up this idea to a more robust model by building screened boxes that stack together on top of a box fan. Read on for instructions on making a solid hop oast (hop dryer).


• Square box fan
• 4 ft (1.2 m) of 2 in x 4 in (5 cm x 10 cm) lumber to raise the fan off the ground
• Lid
o 4 ft (1.2 m) of 1 in x 4 in (25 mm x 10 cm) lumber
o 24 in x 24 in (30 cm x 30 cm) square piece of ¾ in (18 mm) plywood
o 1¼ in (3 cm) screws for the lid
• Trays
o 1 in x 4 in (25 mm x 10 cm) lumber (about 80 inches/2 m per tray)
o Aluminum screening
o Wood glue
o 3 in (8 cm) screws for trays
o Staples
• Tools
o Screw driver
o Staple gun
o Utility knife

The Build

  1. Measure the width of your box fan. For reference, mine was about 20 in (51 cm). You’ll build your trays with this measurement in mind.
  2. Build the trays. For each: a. Cut two lengths of 1 in x 4 in (25 mm x 10 cm) lumber to the length you measured. Then cut two lengths that are 1.5 in (4 cm) shorter. In our example, that’s two 20 in (51 cm) lengths and two 18.5 in (47 cm) lengths. b. Lay out the 4 pieces in a square pattern, with the same-length pieces opposite one another. They should form a box that’s about 4 in (10 cm) deep. c. Apply a thin layer of glue to the end of one of the short pieces, then align it at a 90° angle against the end of one of the longer pieces. Use wood screws to anchor it in place. d. Similarly, attach the second short piece to other end of the longer piece to make a U shape. e. Turn the U so the points face up and apply glue to the two ends. Put the fourth board on top to close the U and screw it in place. f. Spread the screen over the tray and staple it down on all four sides. g. Trim the edges of the screen from the tray.
  3. Cut the 2 in x 4 in (5 cm x 10 cm) lumber into a pair of 2 ft (60 cm) sections. These will form a base for the fan.
  4. Cut the 4 ft (1.2 m) length of 1 in x 4 in (25 mm x 10 cm) lumber into 2 pieces. Attach at parallel sides of the plywood sheet to form a lid with a spacer.

Assemble the Dryer

To use your hops oast, all you need to do is assemble the trays with the fan in a dark, warm place, such as your garage. Then you can run the fan on medium and start the drying process.

  1. Place the fan horizontally on top of the 2 in x 4 in (5 cm x 10 cm) lumber, positioned so that it blows upward.
  2. Put a layer of hops in each tray, piling the hops two or three cones deep.
  3. Stack one tray on top of the fan and stack any additional trays on top of that. You can easily stack a half dozen or so trays.
  4. Place the lid on top of the last tray.

Drying Details

The drying time will vary depending on your relative humidity and temperature, but you can expect to run the dryer for 1–3 days. It’s a very good idea to stir the hops periodically during this time and check them occasionally. The hops are dry enough when the central stem breaks when you fold a cone in half. If it springs back, it’s still too moist. Each pound (454 g) of fresh hops will likely yield about 3 ¼ oz (92 g) of dried hops. Once the hops are dry, divide them into 1 oz (28 g) packages to store in your freezer.

Get hopping!

From steeping specialty grains to extract and hops additions to pitching yeast and racking to secondary fermentation, as well as bottling your beer, CB&B’s DVD, Brewing Great Beer Start to Finish, will get you started down the road to making beer that rivals what you get at the local pub.