DIY coffee roasting [Part two: roaster designs]

Coffee roasting; how complicated could that be? Just heat some beans until they turn brown, and you’re good to go. I recently found some local green coffee suppliers and realized I can buy small quantities for a fairly reasonable price. So I decided I would build my own coffee roasting setup. This is my journal.

While it was appealing to build my own roaster, if a company had a low-priced, good looking unit I figured it might not be worth going through all the effort designing something…

Retail roasters

There are many home roasting options, but in general I thought they were either expensive and not good quality, or extremely expensive and of very good quality. Common recommendations are the FreshRoast series, the Behmor 1600, or a Hottop; I’ve listed them below with a few comments:

Screenshot 2019-04-05 at 10.22.08
The FreshRoast series appears to be a glorified popcorn popper, with a roast size of just a few hundred grams. The price on is much higher than you typically see. A used one should run you about $200 CAD
Screenshot 2019-04-05 at 10.21.24
The Behmor 1600 is a drum roaster and comes with fairly good reviews from amateur roasters. It can typically roast close to a pound at a time, but is difficult to achieve reproducible results (reviews state this, I’m not totally sure why). This seems like a good option, except the price listed above is in USD and is a big initial investment.
Screenshot 2019-04-05 at 10.19.02
The Hottop seems to be the holy grail of home roasting equipment. It allows for extremely reproducible results, has a cooling tray, and offers a lot of control etc. Clearly $1-2 k is out of the question, but if home roasting became a very serious thing, I would consider jumping directly to this and skipping the Behmor-level gear.

Essentially what I found was that no commercially available roaster fit my needs and budget. Apparently there is a significant number of people who feel the same way. So many, that there is a subReddit almost exclusively for us.

DIY roasters

The r/roasting page is full of people who, like me, want to roast beans at home but not spend too much money. The most common solutions are “popcorn air popper” (so smart!) and to a lesser extent, bread machine + heat gun (uh-oh…)

The air popper solution is kind of perfect; the device gets to the proper temperature, and the fan agitates the beans, just like a fluid bed roaster. The major problem that people run into though, is controlling the temperature or batch size. As far as control, most air poppers don’t even have a temperature reading let alone temperature control. People on Reddit seem, for the most part, to be satisfied with letting the popper reach whatever temperature it reaches, and listening for the cracks.

I like the idea of the air popper, but the idea of having such little control over the process sounds terrible. Lucky for me, Mark Sanders already put together directions for adding a thermocouple and temperature control to any existing popcorn popper. Using a Raspberry Pi microcomputer and a few external components, he built a device that, based on the temperature reading from the thermocouple, will turn the heater on or off. He also wrote a program (in Python) that lets you record the temperature as a function of time save your roast profiles, and repeat profiles you liked. Effectively, this will turn your popcorn air popper into a FreshRoast SR500. Sign me up!Screenshot 2019-04-08 at 16.30.09

This got me so excited that I went ahead and ordered all the parts I was going to need including green beans, and picked over Value Village for a popper. From what I read, most popcorn poppers will work, though in some cases a popper may have trouble reaching a high enough temperature. Typically the older poppers will work better. I ended up finding a beautifully age-yellowed popper that was conspicuously clean and oil-free for a measly $5.00

This is going to be so much fun…

DIY coffee roasting [Part one: Louis-Camille Maillard]

Coffee roasting; how complicated could that be? Just heat some beans until they turn brown, and you’re good to go. I recently found some local green coffee suppliers and realized I can buy small quantities for a fairly reasonable price. So I decided I would build my own coffee roasting setup. This is my journal.

I understand coffee roasting on a superficial level. Beans come dried and unroasted (“green”). By heating the beans, they undergo some sort of browning reaction that makes them delicious. Along the way, the beans “crack”, a lot like popcorn would. There are two cracks that happen, and passing through the “second crack” results in an oily dark roast.

With a bit of research I learned the browning process is due to a specific chemical process called the Maillard reaction. Louis-Camille Maillard was a French scientist who first characterized the process while attempting to reproduce biological protein synthesis. In essence, this is a heat-initiated reaction between amino acids and sugars and is ubiquitous throughout cooking. The browning on steak? Maillard. Brown crust on bread? Maillard. And most importantly, roasted coffee; Maillard.

Clearly the resulting compounds of the Maillard reaction are not identical in all of the above examples. During the reaction, a cascade of molecules are created which depend on the specific amino acids present. The resulting molecules are what give these foods their distinct flavors and aromas, however, the exact collection of molecules that are created are very hard to predict and control. For this reason, I am going to assume most coffee roasting discussion will be more of an “art” than a “science”.

[Is “art” what happens when the science is too complicated? The art of coffee roasting, the art of winemaking, cooking as an art; there are countless examples. Is this admitting that heuristic approaches are required because a process is too hard to fully control? By simplifying details, making approximations, and losing exactness, are we admitting science has failed to describe the process? No. What science has allowed us to do is make informed decisions about how and what to simplify to create a working description that matches the tools we have to enact the process.]

From what I have read, coffee gets tasty between 150-230 C (300-450 F). Along the way there are chemical events that happen at specific temperatures. For right now, those details are unimportant. What is important is that the roaster can reach temperatures up to 230 C (450 F), and will provide even heating to all of the beans. Most commercial solutions seem to involve either a rotating drum which agitates the beans as they heat, or blowing hot air such that the air agitates the beans.

I wonder if I can do better…

Further reading and sources:

[1] The first place you should go (Wiki)

[2] Coffee and the Maillard reaction

[3] Coffee roasting and equipment


How to Brew the Best Office Coffee (Manual Edition)

We have gathered here today to brew the best coffee possible with limited time and resources. In a perfect world we would all have a personal barista pulling the cherriest of espresso shots right at our desk. Most of us can’t finance that, and that’s oh-kay. In this guide we will go through your options for brewing the best office coffee, manually. That means no electric moka pots, no Keurig cups, no generic office coffee pots. Just some good ole’ hands-on, DIY, pour-some-water-on-some-beans techniques today.

Note: The following links bring you to the Canadian Amazon, and by purchasing items through the links, I get a small cut. To be clear, I’ve tried to find the best offers available on Amazon, the cut comes out of Jeff Bezos’ pocket, and it helps support the site. However, if you’d like to support the site directly, consider joining our Coffee Club over on Patreon and letting us send you some great coffee.

The manual-brew office coffee guide summary

Screenshot 2019-02-12 at 10.46.56

The details

The intricacies of each process are fascinating and something we will cover in later articles. This guide will only briefly describe what goes into each technique, and propose a few “starter packs” to get you brewing right away. This review should help you to decide which best fits your needs.

French press ($25-$60, no disposable parts)

Simply drop your grounds in the press, add some water and wait. After four minutes, press the plunger to force the grounds to the bottom of the vessel. Pour and enjoy.

Bodom french press – a classic choice

I’ve attached a few links to some very reasonable french presses, though pretty much any you find locally will get the job done. I recommend a press with an easy to clean plunger and screen, since getting old coffee stuck in there will compromise your brew.

Le Creuset – far too fancy for a peasant like me

The major benefit of this devise is that it is one of the easiest processes to get right, and has no disposable filters. The downside is that it’s easy to get

the right water-coffee ratio without using a scale, and this can easily give you over or under-extracted coffee. Another downside is that it’s easy to accidentally leave your coffee steeping too long.

Note: I would recommend against products that combine cup and press, where you brew and drink in one cup. Yes, you press the grounds to the bottom, but your coffee is still in contact, and will slowly over-extract as you drink. No bueno.

Aeropress ($45, disposable paper filter but metal exist)

Like a tiny, thin french press, except when you push the plunger, you press the coffee into your cup, away from the grounds.

While it is easy to experiment with lots of brewing parameters, this method requires nearly constant attention, benefits greatly from the use of a scale, and if you use it as directed, brews only one cup at a time (stay tuned for my Aeropress guide, I have a work-around). On the other hand, the process is done in about 3 minutes.

The AeroPress

Note: the price of these devices seems to have gone up quite a bit since I last bought one. For what it’s worth, this is my personal favorite technique and would happily buy a replacement if I had to. That said, I find my pour-over devices a bit simpler, easier to clean, and less expensive.

Pour-over ($0 – $70, the most DIY, as sustainable as you’d like)

This category really ought to be subdivided, since there are an insane number of devices that are similar but distinct. For the purposes of this review, I will describe what I use at home (metal filter + vessel) and what I use at school (V60-style single-cup with paper filter).

Metal filter pour-over. It sits on top of your cup while you brew

In all cases, the grounds are placed in a basket above the vessel where you will collect the finished coffee. The basket has some sort of filter (some are reusable, most are paper), and the water is poured directly over the grounds. The water will work its way thought the grounds, pass through the filter, and drain into your serving vessel.

At home I use a metal filter I found at a local “this just fell off a truck” junk shop in Hamilton ($5) and a vase from the Dollar Store ($1.50). These were lucky finds, but an equivalent system would be something like the Chemex (which I lust after).

The very popular Hario V60

I like this for my home system because it allows for larger batches to be brewed than the Aeropress, and you don’t need a timer – it will pour through at its own pace. My metal filter and vase are also very easy to clean and produce no waste besides ground coffee. One thing to keep in mind is the size of the basket+filter where the grounds sit. You need to make sure it is large enough to accommodate the number of servings you hope to brew at a time.

Behold, the Chemex


At work, I opt for a smaller, single-cup style like the Hario V60 (featured above). I only brew for myself, and I only drink one cup at a time. This system lets me brew directly into my cup, and if I use a paper filter, the number of things I need to wash is exactly one. The V60 is a beautiful device, but there are also cheaper options. I would stay away from plastic or rubbery versions as those tend to be harder to clean and have the potential for leaching flavors.

As simple as the pour-over is, you still need to add water periodically as the coffee drains. The ideal technique is not to pour all of the water right away, but to add it a several intervals. This means the french press still wins in terms of simplicity.

“Cowboy” Coffee (rad as hell)

Imagine a french press, but you lost the plunger. This is by far the simplest method,  and seriously, a totally fine way of going about it. Just put some grounds in a pot and pour some boiling water. Wait a few minutes and slowly pour your coffee into a cup, trying to keep as much of the solid matter in the pot as possible. Or just drink out of the pot. You do you.

Maybe this sounds silly, but it’s actually pretty decent. Yes, you are going to be chewing your coffee, but you can still brew a delicious cup. I unexpectedly ran out of filters at the office recently**, and was pleasantly surprised. I even considered ditching the V60 and filters in favor of the rustic approach. At the very least, I can confidently say I preferred this to the ancient pot in the break room.

**I also didn’t have a pot to brew in, so I dug around in the break room and found an old flower vase. I cleaned out the dirt and have been using it since. So for those keeping score, I exclusively use vases for brewing my pour-over coffee.**

Concluding Remarks

There really is no right or wrong way to brew your coffee. I like manual techniques because they give me an opportunity to really take a break from work and focus on the task at hand. This isn’t what everyone is looking for from their meditation coffee practice, but it’s something I value. If you are looking for a more hands-off, efficient way to make your coffee, stay tuned for our guide to electric and automatic brew methods.