DIY Coffee Maker for Outdoor Adventures

Being on an adventure in the outdoors shouldn’t mean you have to forego a decent coffee. In fact, the outdoors is a great place to enjoy a coffee, with it even being said that coffee tastes better outside. The problem with household coffee makers, like my stainless steel pour-over dripper or stovetop moka pot, is that they are bulky and/or heavy - not what you really want when hiking or bikepacking. There are a bunch of clever devices made for the outdoors, but these tend to have two drawbacks for me: the price, and the use of plastic*.

I got thinking about how I could make a pour-over coffee dripper that is lightweight, yet stable, packable, and still makes a good brew. It also needs to be relatively cheap and easy to make, ideally avoid the use of plastic, and offer a little more control (and less mess) than attaching a cloth to the top of my mug with a rubber band!

The result was a simple combination of an aluminum cup (such as a pudding mold) and some old bicycle spokes that fits easily into a mug for packability and weighs less than 30 grams (1 oz). This is a flat-bottomed dripper, similar in shape to the Kalita Wave. The trick to its packability is the retractable wire arms that slide inside the dripper when it’s not in use. But this isn’t their only function - they also hold the filter off the bottom of the dripper, allowing a better flow of coffee by keeping the drain holes uncovered.

It's also easy to make without any special equipment, materials, or skills - perfect for an Instructable.

And now, in the spirit of the outdoors, I’m going to show you how to make it outside!

* I can see why so many outdoors coffee makers are made of plastic, due to its durability and weight, and I know that some plastics are quite stable with hot water. But, for this project, I wanted to go plastic-free.

This may be a simple project, but there are a few things to consider before you rip into it. The first is slightly obvious, but ideally the coffee dripper should fit inside the mug you use on your outdoors adventures. This isn’t just to minimize the space it takes up in your pack; the wire arms have a tendency to pull out and snag on things otherwise. The second is to make sure the dripper cup fits your filters, preferably before you go out and buy them!

Materials 

1. Aluminum cup, such as a pudding mold, baking cup, or similar, to fit inside your coffee mug. I used the Daily Bake pudding mold, which has a top internal diameter of 70 mm and height of 60 mm.
2. Stainless steel wire: two lengths approximately 20 cm long and 1.5-2 mm in diameter (plus spares for trial and error). I used 1.8 mm diameter bicycle spokes from a wheel in the scrap bin of my local bike shop, which worked perfectly.
3. Coffee filters: I tried filters from Hario and Kalita, as well as cotton filter cloth. More details on these just a little further down.

Tools

1. Drill
2. Small drill bits (2-4 mm)
3. Pliers (with wire cutters)
4. Ruler and measuring tape
5. Marker pen
6. Fine metal file
7. Emery cloth (or sandpaper)
8. Clamps (optional)
9. Eye protection

Filter types

Here are some thoughts on a few different types of filters and what cup sizes they work with. These aren’t necessarily the dimensions of the actual drippers they’re made for; just what seems to fit from what I’ve seen. Using cups with both the heights and widths at the ends of the ranges I've given may not work as well.

Kalita Wave 155 (flat-bottomed): I see these filters working best with a cup with a top diameter of 75 mm (70 mm at a pinch) to 90 mm and a height of 50-70 mm.

Hario Pegasus size 01 (trapezoid): whilst not made for this shape of coffee maker, the bottom sides can be pinched out to make a flat base. These are a great option as they pack well and can be folded to fit different sizes of cup. I see these filters working best with cups with a top diameter of 65-90 mm and a height of 50-70 mm.

Cloth filters: just cut to the size you need! These should be made of cotton; the type used for making cheese is good, but there are plenty of other types that work, such as muslin. If you can get ready-made bags for making cheese, you can cut a corner off to make a conical shape that fits nicely into the cup.

For taste, I prefer the cloth filter, followed by the trapezoid filter and the flat-bottomed filter, although this could just be down to personal preference and/or the type and grind of beans I’m using, and there wasn't much in it. Cloth is great for avoiding waste but isn’t such a good option if you don’t have the opportunity to dry it out. 

The spacing of the holes, and therefore the wires, is a balance between the stability of the dripper and the filter being able to be held off the bottom of the cup. I went with 34 mm, which seems to work well. If anything, I would reduce this slightly next time.

I marked out the locations for the holes by running a flexible tape measure around the bottom of the cup, from which I could find the opposite points by taking any two points half the circumference from each other. I then measured an equal distance each side of these to get the locations for the holes.

The holes will be drilled a short distance from the bottom of the cup, but don’t worry about marking their height for now, that’s covered later.

I was originally going to simply say “drill the holes”, but this jig was so easy and made the process so much simpler than the inevitable battle of a spinning drill bit against a convex surface (even with a pilot hole) that I had to include it as its own step.

Find whatever scraps of wood, or other flat objects you have to hand, and lay the drill down on its side with a platform created slightly below the drill bit. Use clamps to hold the drill and wood in place. A willing helper with a steady hand would suffice in lieu of clamps.

The exact height of the holes above the bottom of the cup is a balance; holes further from the bottom will make the wire arms sit at a greater angle, holding the filter more off the bottom of the dripper and making the dripper less likely to slide around on the mug, but also making it hang further into the mug.

Now that you have a drilling jig, I can simply say “drill the holes!”

Make the holes for the arms only slightly larger than the wire - this helps stop the arms from flopping around while you set the dripper up.

You’ll also need to drill the drain holes in the bottom of the cup. I drilled two holes, close to the wires so that the filter is less likely to sit on and block them. I started out with 2.5 mm diameter holes, but increased these to 3.5 mm during use, to get a better flow.

Gently smooth off any rough edges with a file and emery cloth or sandpaper.

There are several ways to do this, and whilst a wire bender would make it easy, it isn’t necessary. I just used a pair of pliers and a flat work surface; a vice also works.

Don’t worry about where exactly to bend the wire for the first bend as you can trim it to length later. Just start approximately half the spacing of the holes from the centre.

The bending itself is quite straightforward: get a firm grip on the wire with the pliers, hold the wire on the end of your work surface with the pliers just off the end, and rotate the pliers whilst maintaining downward pressure on the wire. When the wire has bent enough for the pliers to be above the work surface, move them and the wire off the edge to make it easier to finish the bend through to 90 degrees.

The second bend is done in much the same way as the first, the key step being to get the spacing of the bends to match the spacing of the holes you’ve drilled. I found gripping the wire 1 mm beyond where I wanted the bend to end up worked well, but this did take some trial and error - hence I recommend having spare lengths of wire!

At this point you can insert the wire arms from the inside of the cup, before adding the finishing bends. These will help keep the arms with the dripper, so you don’t have to go looking for separate parts in the bottom of your pack, as well as help stopping it from sliding off the mug.

These last bends are a little trickier to make as you will have a cup attached to the end of the wire. You will either need to find a raised surface to bend the wire on or use a vice to hold it whilst you bend it.

Avoid the temptation to make the arms too long, which will mean they don’t fit inside your mug. Having them longer also makes them more likely to fall into a downwards position before you put the dripper on the cup.

After adding the final bends, cut the wires to length and smooth the ends off with a metal file.

There you have it, a coffee maker for your outdoors adventures! You can store flat filters and coffee tucked down in your mug under the coffee maker, with it held in place by a rubber band for a great packable unit.

I really hope this inspires you to make your own coffee maker and get out to the wild to enjoy it. I’m sure lots of you will have ideas to improve this concept, so please get tinkering and share how you’ve made yours.