Roast Your Coffee In Two Stages – Now With OpenCV Tricks

http://blog.chewxy.com/2014/02/13/you-should-double-roast-your-coffee-and-opencv-tricks/

by boyter • 12 years ago

35 27 12 years ago

blog.chewxy.com

why is uneven roasting bad? if you want complexity in the coffee wouldn't a variety of roasts give variety / depth of flavours? is there some technical reason while all beans should be roasted the same?

cpenner4617• 12 years ago

I've never really thought about this per se, but the first thing that comes to mind is that if things are uneven, it's generally more like some beans are burned and/or some aren't roasted enough. Either of those scenarios are going to produce undesirable flavors. I think the more common way to capitalize on a variety and depth like you mention is to roast different types of beans separately and then mix them. That said, there's a lot of complexity and variety just in single bean (or, single origin) roasts, differing levels of roasting bring out different flavors.

mertd• 12 years ago

Would you like half of your steak well done and the other half rare?

standeven• 12 years ago

If you were to blend the entire steak together, would you notice?

cema• 12 years ago

Steak is normally not ground, unlike roasted coffee beans. So there is no mixing. On the other hand, I know at least one coffee company that sells a mix of dark and light ground coffee (Melitta, in the US).

cpenner4617• 12 years ago

I've been roasting my own beans off and on for several years, the quality is far better than anything you can get at the supermarket and even most coffee shops (unless they are doing their own roasting). Buying green beans is quite a bit cheaper as well, so you get the best coffee possible at the best price - win win!

The air popper in the article is a popular low cost way to get into home roasting, but I started with just a heavy pot and lots of stirring, hard to keep things even. After a short while I built something pretty close to this: http://biobug.org/coffee/turbo-crazy/ Still a lot cheaper than something like the Behmor, but able to easily roast 1/2 lb at a time.

What I love the most about this is the analysis of the roast with opencv, will definitely be trying that for my next roast!

chewxy4• 12 years ago

author here - boyter informed me that this was front page on HN.

I'm actually seriously contemplating building a rig. I have 3 spare flashes for my camera and my table is a frosted glass table. It should be able to give uniform lighting to the beans for visual analysis.

cpenner4617• 12 years ago

Nice. Trying to think through that - would you be shooting the flash through the frosted glass to diffuse the light evenly?

bradly• 12 years ago

Do you know any good resources for buying raw beans online?

fallinghawks• 12 years ago

sweetmarias.com has a huge variety of beans and many pages of how-to with photos.

ScottWhigham3• 12 years ago

As another home roaster, I often see people talking about how much cheaper buying green coffee beans is vs. buying roasted beans. I thought the same before I really got into home roasting.

My perspective is that, if you only consider "price" as your differentiator, yes the green coffee beans are cheaper. If you look at the Sweet Maria's site, they are selling just-roasted Rwandan coffee for $15 per pound [0]. They sell the exact same green beans for $6.35 per pound [1]. But that's deceptive because (a) Sweet Maria's has a $15 minimum purchase (so you can't buy just 1lb), and (2) the $15 roasted coffee includes shipping. I just checked and, to ship 3lbs of coffee (minimum order of green), would cost $11.30. So my "out the door" price for 3lbs of green is $30 which makes it $10 per pound. If you compare that to the $15 "out the door" price for their roasted, I'm saving $5 per pound. Sweet.

But how long will it take you to roast those beans? Two adults probably go through one pound a week. So you saved $5 by buying online, but it takes me about an hour a week to roast a pound of coffee using my Behmor. Even if it only took me 30 minutes, would I trade 30 minutes of my leisure time for $5? That's the part that people don't consider enough, I think. At this point in my life, I am enjoying trying all the different coffees and learning about the various roasts - so the Behmor stays for now. In five years though once I've learned all that I can learn and have become more "refined" in my tastes", I wonder though whether I'll still want to be spending an hour a week roasting beans...

[0] http://www.sweetmarias.com/sweetmarias/roasted-coffee.html

[1] http://www.sweetmarias.com/sweetmarias/rwanda-kivu-kanzu-1-l...

cornellwright• 12 years ago

I tried roasting my own beans once and it was a ton of work and made a lot of smoke. I just buy 5 lbs at a time from a place on the internet which roasts when I order and ships the same day. It tastes great and I don't have to deal with roasting.

chewxy4• 12 years ago

Do you finish said 5 pounds (2.5kg) in about a fortnight or so? Just curious

pinko• 12 years ago

Link?

2muchcoffeeman• 12 years ago

A unit like the Behmor comes with an after burner to burn the excess smoke. So you can home roast without the hassle these days.

A project like this is fun if you also enjoy the tinkering, but given the markup on roasted beans, spending money on an appliance is very economical.

ScottWhigham3• 12 years ago

From my comment in this thread:

If you go through a pound of coffee a week (which is likely for two adult coffee lovers), that means you'd have to spend almost an hour per week to roast your own coffee using the Behmor.

It just depends on what "economical" means to you, I suppose. One hour per week roasting/managing is significant to me. If I could find a place that would sell me just-roasted beans in 5lb or more bags, it might be worth it. I paid $300 for the Behmor and I pay about $8-$10 per pound shipped for green coffee. If you said, "Scott - here are some great tasting beans that we'll roast for you right before we ship them, and they are $12 per pound", I would sell my Behmor. At this point I've learned most of what I'll learn about roasting coffee - now it's just a matter of spending that hour a week. If I could pay a company $2 per week to reclaim that hour though...

tdicola• 12 years ago

There are lots of American small kitchen appliances that pull more than 1100 watts, including kettles. Most outlet circuits are rated for 15 amps so it's not uncommon for some appliances like toaster ovens or vacuums to use 1800 watts. I think the reason most Americans don't own an electric kettle is that tea isn't nearly as popular as coffee, and most folks use a dedicated drip or single serve coffee brewer.

chewxy4• 12 years ago

Yup. It's also 13A in UK. I'm using 10A as a rough guide - mainly to illustrate the power differences between AU and US. The post has now been updated to reflect your comment. Thanks

JasonCEC• 12 years ago

If anyone here is interested in improving their home roasting, check out our services for Quality Control and Flavor Profiling [1].

I'd be happy to set you up a free account as a home roaster, and I think feedback from the HN community would be really helpful!

[1] www.Gastrograph.com

ScottWhigham3• 12 years ago

I loved this - this is why I love HN. Although roasting the beans in my oven would terrify me - the chaffe could so easily catch fire, couldn't it?

I own the Behmor - I'm rather new to it (< 50 roasts). I'm happy with the purchase however I would caution anyone interested that (a) there's a massive learning curve (as OP points out), and that (b) even though it is marketed as being able to roast 1 pound of coffee, you will only really get a light-to-maybe-perhaps-kind-of-medium roast if you put a full pound of coffee in the drum. I only learned this after going through about 10 pounds of coffee (~20-30 roasts). I like a really dark roast - what I learned is that I can only roast 10 ounces at a time with the Behmor. Check out the top-rated review on Amazon - the guy says he can only roast 7-9 ounces at a time.

After looking at $800 roasters, I'd still buy the Behmor if I was new to this and wanted a roaster. But here's the thing: to roast 10 ounces of coffee takes about 35 minutes - you have a 15-22 minute roast followed by a 12-13 minute cooling cycle. If you go through a pound of coffee a week (which is likely for two adult coffee lovers), that means you'd have to spend almost an hour per week to roast your own coffee using the Behmor. And this roast - there's about a five minute time period in the latter/end part of the roast itself that has to be attended. So you start your roast, come back 10-12 minutes later, wait for the cues you need, and then you can go on with your life.

And you know what isn't great? The Behmor's temperature sensor will shut the unit down if it's cold outside (like below 30 degrees F). When it's cold, you'll have to get your roast prepared indoors, then take it outside, and start the roast. And that five minute period where you have to watch your roast? Let me tell you - it sucks to have to monitor a roast outside in 16 degree weather!

That said, after roasting my own, it's almost unfathomable to me at this point to want to quit using the Behmor and go back to someone else's roast. I've enjoyed the learning curve.

cpenner4617• 12 years ago

Wow that seems like a very long time (especially on the cooling side). Using my Turbo Crazy setup (see other comment here), I hit second crack in about 10m (which I'd like to get pushed out to about 12m I think, but the temp control on my convection oven is not very precise). For cooling I dump the beans into a 2 sided perforated oven pan (I can't find an exact link, but imagine 2 of these that attach together: http://www.amazon.com/dp/B002KE5OLY/) and shake it gently over a fan, they're cool in about 2-3 min. I figure on about 15m per half pound of coffee.

FWIW I've never had chaff catch on fire, and it seems to me that my setup is probably cranking a hotter/more direct heat than an oven would.

But yes - roasting in the cold stinks - and yet I still do it as well. :) On the plus side, that cooling time drops to a min or so when it's 30F!

Roast Your Coffee In Two Stages – Now With OpenCV Tricks

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