So I was faced with this problem. I am the only person In our house that drinks coffee. The Keurig at work has exposed me to the K-cup coffee selection. Along with this I don't really drink enough coffee outside of work to justify spending $60 for a single brew pot. So while up with our newborn I started to experiment with K-cups and various sundry items to try and create device to make K-cup coffee.
Step 1: Mark 1 Test Prototype
Like any good tinker nearly as soon as I brewed my first K-cup I proceeded to dissect the spent canister to unlock its secrets. Of course it's just a single use filter pack sealed in a plastic cup. This along with tearing apart a brewer in my Keurig problems instructable, I had a several good ideas on DIY brewers. But I never moved forward with them. Then I thought of our last camping trip and the coffee we had to drink. Not the greatest thing. So how could you make K-cup coffee while camping; with no power? Really just need a water tank that can seal to the top of the K-cup. Is there anything off the shelf that might work or get me in the ball park?
This led me to the plumbing supply store...
My first build (seen above) came to me while thinking on this while roaming the hardware store with a K-cup inserting it into various pipes and fittings. ( It did draw some interest.) I found that a 1.5" PVC repair union was the exact size needed to capture a K-cup.
Simply cut out the inner lip ID from the non O-ringed side of the union to accept the K-cup. For ease of testing I hot glued the O-ring into its groove (kept falling out) in the upper half. The threaded ring was also glued allong the outside surface holding it to the ''lower' section making assembly easier.
Once clamped poke holes in the top and bottom of the K-cup package and pour boiling water in the 'top' section. It's a slow process but works pretty well.
Although this design works the PVC imparted that new PVC taste to the coffee. This may have faded with use but more importantly I had concerns about chemical leaching from the PVC plastic with prolonged use with boiling water.
This led me to Mark 2.
Step 2: Mark II
Mark II came to me while I was up in the middle of the night between newborn feedings.
I discovered that the standard baby bottle mouth is the right dia to capture a K-cup also. And baby bottles are BPA free / can take boiling liquid with no issues and with a little trimming of the nipple they come with their own food safe gasket.
So lets get started!
Step 3: Gather Materials and Pick a Baby Bottle
For this build you will need
- 1 Baby Bottle
- Knife and or dremel with sanding drum or the like for cutting/trimming
- Scissors or knife to trim the nipple
Picking a Bottle:
There a lot of bottle styles out there. I settled on using a Phillips Avent bottle seen above for several reasons.
1: It will hold around 5oz of water (this is just right for the size / strength of coffee I usually drink.)
2: In test fitting the mouth design of this bottle with its oversized clamp ring made getting the K-cup passed though the thread area easier.
3: the most important reason is the baby doesn't like these bottles and I won't get in trouble for destroying one.
If you are going to have buy a bottle for this build other bottles should work fine. The thread designs seem to vary from brand to brand but the critical mouth dia. seems to be standard.
Keep in mind also if buying a bottle (spoiler alert) the bottom will have to cut off to complete this build. There are bottle styles that have detachable bottoms for easier cleaning. Also the liner drop in styles usually do not have a bottom at all.
--- Food for thought on the later option.----
Drop in bottles tend to have holes in the cylinder pay attention when shopping also because the liner bottles 'container' does not actually contact its contents they are thinner walled and potentially molded in lesser grade plastics etc..
Step 4: Trim the Nipple Ring
Now lets start disassembly and trimming:
Simply unthread the ring from the bottle and then remove the nipple.
With your cutting utility, carefully, remove material from the inside diameter of the ring until the K-cup will fit inside as seen.
This oversized inner ring threads I trimmed material from also giving me more room to seat the K-cup.
Step 5: Trim the Nipple
The clamp ring part or our micro brewer is done. Now make the gasket.
Basically cut the center section from the nipple so you are left with a just a sealing ring.
Scissors were the easiest thing to use for me. Again be careful .
This gasket will be placed on the top of the K-cup after it is inserted as seen in the last pic.
Step 6: Remove the Bottle Bottom
We have a clamp ring and a gasket all we need is a way to get boiling water in our unit.
The last step, to cut the bottom from the body of the bottle is pretty straight forward. This will create our water vessel.
If you don't have the means to do this or just want a short cut as mentioned earlier some bottle designs have a bottom that unscrews for easy cleaning. And some take drop in liners and have no bottom at all.
If you use one of these you can skip this step, assemble and use.
Ideally I'd use a drill motor and hole saw for this but at the build time I didn't have one with me. I started the hole by boring a knife through to make a starting point. to save a bit of time i finished with a dremel with a cutting bit and drum wheel.
You could melt out the hole with a soldering iron (be sure to do this one in a well vented area. Or just hack the bottom off with a coping saw.
However you get it done be safe.
Step 7: Assemble and Make Some Joe
With the bottom out of the bottle assemble the unit will look as seen above.
Poke a hole in the top of the K-cup foil.
Then either poke multiple holes in the bottom (don't go too deep you will puncture the filter)
Or cut the rim off the bottom of the K-cup as I did. The later for the bottom will make your coffee faster.
Now just boil or heat some water and pour it in while holding the brewer over your cup. (The separator in the pic holding the unit over the mug is just a piece of plastic from an old notebook binder with a hole in it)
Drink coffee to test quality.
Always rinse/clean your unit between uses.
Now you have a portable K-cup brewer that can be made for less than $5.
Step 8: Closing Notes
There you have it. Go hiking and camping and take all the fancy coffee you like.
It should be said that this unit being gravity fed will take a bit longer to brew than your Keirig machine. But for $5 I'm not complaining.
The tea bag style drink packets can also be used with this unit. You will just need something to keep the bag from falling out of ring mouth course. A spent K-cup with contents removed would do nicely. The reusable K-cup fixtures should work with this unit too though I've not tested to confirm.
I am working on a stand for countertop use I will post an update if / when I get it to my liking.
Thanks for tuning in!
Megan House made it!