January 11, 2014

An Ideal Coffee Roaster for Me/私には理想的なコーヒー焙煎機

I previously used a 26-cm diameter shallow, alumite pot to try to roast 200 g of coffee beans, but I failed, as I described here. After much thought, I decided to give the pot another try, but this time after making some holes at the bottom.
ここに書いた通り、以前、直径26 cmの浅いアルマイト鍋を使って、コーヒー豆を200 g焙煎しようとしましたが、失敗しました。いろいろ考えた結果、その鍋をもう一度試すことにしました。今回は底に穴を開けてからです。
300 g (not 200 g) of Brazilian coffee beans:
コーヒー豆(ブラジル)、300 g(200 gではなく): 
For the first 10 minutes, I placed this semicircular lid on the top.
After 15.5 min. roasting:
The beans are now 250 g in weight.
豆は重さ250 gになりました。 
16.7% weight reduction. Sounds perfect!
I know I need to refine my pot roaster slightly so that I can shake it more easily, but I'm pretty sure this is going to be an ideal coffee roaster for me.


Fräulein Trude said...

The pot reminds me a lot of an aluminium sieve I inheritated from my grandmother. I think the sieve is stored somewhere in the basement. Must search for it to run a coffee roasting test.

Hiroyuki said...

Kiki: Do give it a try and report on your findings in your blog!

I think that with a sieve, you need to control the heat more carefully because it has more openings.

Think of coffee roasting as a two-phase process: Drying phase (first 10-12 min.) and chemical reaction phase.

Make sure that chaff starts to come off in 3-4 min. If it does earlier, say, 2 min., you have to lower the heat.
If the beans start to crack at, say 9 min., you have to lower the heat.
When the beans are fully dried in 10-12 min., turn the heat to maximum to cause chemical reactions. That is, let the beans crack and expand fully! 1st crack last for 1-2 min. I usually stop after 1st crack. You can bring them to 2nd crack if you want bitter coffee.

I will write more about coffee roasting, together with the features of my three roasters (milk can, kettle, and shallow pot) in the near future.

Hiroyuki said...

Kiki: Forgot to tell you about one more thing: With a sieve, you will need to place a lid or something similar on the top for the first 10 minutes to keep the humidity inside the sieve high.
Nakagawa-san explains why in this weekly video, starting at around 1:27.
He uses a fan-like object to cover the top of the net.

Fräulein Trude said...

Thanks for your advices. First I will have to buy a cheap gas cooker and order some green beans online. Husband is totatally against home roasts but we will see (he is the coffee geek, laugh)

Hiroyuki said...

Kiki: Was the explanation of Nakagawa-san clear to you?
You must keep the humidity inside the "te-ami" (lit. hand net) high in the first 10 minutes of roasting to let the moisture out of the beans (but keep the flavors in) by placing a lid on top. Otherwise, your coffee beans would likely to be tasteless.

Depending on the size of your sieve, you may want to buy a cyclone type gas burner. For my 26-cm diameter pot, a common portable gas burner (flames directing outward) works fine. And, because of its large diameter, I don't shake it vertically but horizontally.

The smoke and chaff generated during roasting can be off-putting. You can reduce the amount of chaff generated considerably by rinsing in water to remove chaff before roasting. In that case, you have to dry the wet beans with dry cloth.

Hiroyuki said...

Kiki: I know how your husband feels about home roasting. I know of all other home roasting methods, like popcorn popper, hot air gun, and fry pan (watched them all on YouTube). None of them appeals to me.

The milk can roaster is a great invention of Nakagawa-san, and I must add that my shallow pot is even better (laugh).

One more caution:
Even professionals can make inappropriate suggestions. See how this guy roasts coffee:
The roaster is not in direct contact with the flame but is 20 cm above it. With this way of roasting, the beauty of direct-flame roasting is completely lost!
Do you believe that this roaster is sold for 4,500 yen?