Coffee Roasting

Coffee Roasting

Coffee Coffee. How did we discover that a seed grown at high altitudes, and then fermented, dried, milled, roasted to varying degrees, ground, and brewed, would be so satisfying to drink in the morning? I wonder this almost every time I make myself a cup.

What doesn't require a machine (yet, at the most basic level), is roasting my own beans. This blog post will hold my findings and statistics as I learn to roast my own beans at home, and as I attempt to become a small batch coffee roaster! I know I will need to learn a lot, but I am excited to perfect the process. I can't wait to share my roasts with friends (if they are any good), and start learning the science and terminology behind the profession.

Currently, I brew my coffee in an AeroPress or a Hario V60 setup. I just recently purchased a temperature controlled kettle, the Fellow Stagg, to make sure the water temperature is just right and to easily control the water flow when making a pour over. I also use the Rhinowares grinder to freshly grind the coffee right before brewing (clearly, I bought it because it fits the rhino theme). I like to keep my setup as simple as possible, with just the two main brewing methods as my options. This does not allow me to create a true espresso or steamed milk, however, so that will be something I may invest in in the future.

Stay tuned for updates to my Instagram and this blog! If there is anything that requires a video I may also publish something to the YouTube channel.

The beans I am using today are Costa Rica SHB. SHB stands for strictly hard bean, which is coffee that is grown above 3,900 ft. GHB (good hard bean) is grown at 3,300 to 3,900 ft, and MHB (medium hard bean) is grown at 1,600 to 3,300 ft. From my understanding, the higher altitude beans are usually more consistent in flavor.

I purchased a 5lb bag of green beans from a seller on eBay to start experimenting with. I'm not entirely sure if these are high-quality beans, but they are inexpensive and accessible. Sourcing high-quality beans may be the trickiest part of the business. For now, I will be roasting roughly 100 grams at a time.

06/27/18 First Attempt Roasting Coffee


  • 101.5 grams of coffee going in.
  • Starting at 13:18 with 3.5 heat (electric stovetop).
  • Preheated pan.
  • Total time: 9:48.5 on heat / off heat (lifting up pan occasionally).
  • Constant stirring with a small whisk.
  • 86.2g left after roasting, but dropped a couple beans.

Result: Waited 48 hours before drinking for off-gassing to take place. Doesn't smell particularly strong or delicious. TERRIBLE, HA! Sour. Both bitter and acidic. Red color. Low aromatics.

Findings: I didn't roast them long enough. After roasting, beans lose about 20% of their weight.

06/29/18 Second Attempt Roasting Coffee


  • 100.3g of coffee going in.
  • Starting at 12:42 with 3.5 heat.
  • Preheated pan.
  • Total time 11:14.
  • 83.6g left after roasting.

Result: Tried cupping for the first time two days after roasting. It didn't taste very good, and I wasn't sure if I followed the cupping method correctly. Tried the coffee again on July 5th using an AeroPress. Still smells bitter. The color looks a little better with less red. It tastes a little bit more like coffee! Not sure I would want to drink the entire cup, but it's not so bad that I want to spit it out.

Findings: Stovetop may simply be too inconsistent to be able to roast coffee. Some beans look a little burnt while some aren't roasted enough. I might try roasting them with lower heat next time. If I could figure out a way to keep the beans in rotation without using a whisk they might turn out better.

07/31/18 Third Attempt Roasting Coffee


  • 224.9 grams of coffee going in.
  • Starting at 11:30 with 3.5 heat.
  • Preheated cookie sheet and Whirley Pop.
  • Total time 25-27 minutes (didn't get a super accurate number on this). This seems a bit long. Probably going to turn up the heat a bit on my next try.
  • 188.7 grams left after roasting.
  • 16.1% moisture loss / bean weight loss


A month flew by! In that time I did some more research on how to roast coffee at home. I found a Whirley Pop Popcorn Popper for $10 locally, which is another method to home roasting that is popular. A Whirley Pop has a built in metal arm with a hand crank that allows you to keep the beans constantly moving. If this works out well I might figure out a way to attach a small electric motor to spin it for me. (This might be a bit lazy, but the roast will only be more consistent because of it...)

This time I started with more than twice the amount of beans as before, 224.9 grams. I tried adding a bean to get a perfect 225 grams, but it went up to 225.1 grams. That bothered me.

Because of the fact that I was using the Whirley Pop instead of a frying pan, I kept the heat the same at 3.5. The Whirley Pop model that I have is the aluminum version instead of the stainless steel version. I didn't want to pay $50 for that model, so I used a cookie sheet to help distribute the heat more evenly.

Findings: While the consistent color was promising the coffee was not appealing to drink. It had too much body, and no cocoa or raw sugar notes coming through that I'd expect from a Costa Rica bean. It may be that the beans are bad, but I think the electric stovetop might not be providing enough heat. Our kitchen has recently been updated to an induction stovetop so I will try again at a higher heat setting to see if I can get the roast to complete faster.

By Nathaniel Hirschler

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