Milk Can Coffee Roasting/ミルク缶コーヒー焙煎

Japanese Coffee Japanese Food
In Japan, today is the last day of three consecutive national holidays, and I finally got around to trying to roast some coffee beans with my milk can roaster.
A milk can roaster is no joke. Nakagawa-san of Flavor Coffee sells it for 5,000 yen (including 1-kg green beans). He claims that it can roast coffee beans just like a commercial roaster.
If you ever decide to make one by yourself, refer to the thread that I started on eGullet a long time ago.
Note that the milk can is 13 cm in diameter and 18 cm in height. The roaster is designed so that first crack occurs in 12-14 minutes when used with a 2,500 kcal portable gas stove. The size and the number of the holes at the bottom determine the roasting time. The height of the can is also important.
ミルク缶は直径13 cmで、高さ18 cmです。この焙煎機は2,500 kcalの携帯用ガスコンロで12~14分で1はぜが起きるように設計されています。底部の穴の大きさと数が焙煎時間を決めます。缶の高さも重要です。 
I decided to do the roasting in the garage.
The roaster is capable of roasting up to 200 g of green beans at a time, but Nakagawa-san recommends roasting 150 g so you won’t get tired from shaking the roaster. You need to shake the roaster constantly once per second for 14-16 minutes.
この焙煎機は生豆を一度に200 gまで焙煎できますが、中川さんは焙煎機を振り続けて疲れないよう、150 g焙煎することを薦めています。1秒に一回コンスタントに14~16分も振り続ける必要があります。
165 g of green beans:
生豆165 g: 
The gas stove has 2,600 kcal/h. I started with the heat set to high. The chaff started to come off 2 minutes later. Bad sign! It should start to come off in 3 minutes. I lowered the heat to medium. You have to reduce the moisture inside the beans for the initial ten minutes.
Ten minutes later, I turned the heat to high, and the beans started to crack immediately. I reduced the heat to medium again. Twelve minutes later, I turned the heat to high again. Fifteen minutes later, I stopped roasting, before second crack.  
ガスコンロは2,600 kcal/hです。火力は高にして始めました。チャフが2分後に飛び始めました。悪いサインです!チャフは3分後に飛び始めるようにしないといけません。火力を中に下げました。最初の10分間で豆の中の水分を抜く必要があります。
I immediately cooled the beans. I have a cooler, given to me by Nakagawa-san.
Coffee beans, roasted for 15 minutes:
I then transferred to a metal sieve.
Weight: 145 g
重さ:145 g 
Compare the beans (right) with the Mocha beans bought from Flavor Coffee:
I ground some of the just roasted coffee beans.
Naturally, the coffee grounds bloomed remarkably.
More gas coming out as I poured water.
End of brewing.
I used a Matsuya wire-frame dripper, but brewed coffee like the Melitta/Kalita way.
Resultant coffee:
I drank a cup,
and found it was good although a little bitter.

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