Yirga Senior Member Joined: 3 Feb 2006 Posts: 659 Location: Big Bend Expertise: Just starting
Posted Mon Aug 7, 2006, 5:21am Subject: Microwave Roasting?
Anybody have microwave oven coffee roasting experience they'd like to share? I get the idea it's lower in the coffeegeek heiarchy than instant coffee, moka pot and whirly blade, but I've had some interesting results just trying to explore the possible reasons it's scorned so much. I like to swim upstream and after years of orthodox cooking I took on the challenge of microwave cooking after years of using the thing mostly like most people do -- reheating left-overs, popcorn, and heating water. It actually can do stuff like, saute aromatics, very well and fast if one spends a few moments thinking about the physics involved.
For me, coffee roasting is a lot like the principles involved in flavor enhancement achieved in cooking -- browning, toasting, roasting, grilling and concentrating flavors, and especially, caramelization of sugars. All involve the application of heat to reduce moisture and raise the temperature of food above the boiling point of water (way short of burning and charring). Microwave ovens are good at heating the water in food items to the point boiling occurs and the fans in them pull a slight vacuum and speed up moisture loss which at some point the absorption of microwave energy is concentrated to raise the temperature of any oils present (oils actually absorb microwave energy better than water) and achieve the higher heat associated with flavor enhancement.
But, back to microwave coffee roasting. Any, thrill of victory or disaster of defeat? (I take no meds or abuse no alcohol or drugs -- so forget about those wise cracks! -- but if it makes you feel better, sock it to me!).
Posted Mon Aug 7, 2006, 6:13pm Subject: Re: Microwave Roasting?
"I seem to remember someone selling coffee beans in a bag like microwave popcorn."
That sounds like a great idea .. if it worked. The smoke is what throws a wrench in the works .. unless quantities are small. Interestingly .. some months ago I adopted a old microwave ... for no good reason .. to put in my gardening lab in the garage ... I have some small bags of left over beans .. I think I'll give it a try.
Posted Mon Aug 7, 2006, 7:16pm Subject: Re: Microwave Roasting?
"Anybody have microwave oven coffee roasting experience they'd like to share? "
HOLY COOooooW !!! Four ounces of Brasil Santos up in smoke !! Two minutes with the beans in a glass bowl not a good method apparently !
A nice demo though of a microwave cooking from the inside out ... the beans in the center of the glass bowl were all VERY black ... made Starbuck's look light roasted ... filled the bloody house with smoke ... the fastest french roast in roasting history.
I suppose one could agitate the beans and reduce the power but not sure what good that will do .. could not hurt ofcourse .. the whole house stinks like burnt pop corn.
As a master roaster said to me " When you roast you are the master of your own fate ". I'm a bit stymied on this one ... What next ?
Posted Mon Aug 7, 2006, 8:37pm Subject: Re: Microwave Roasting?
I just purchased Ken Davids book in home roasting. He talks about microwave roasting.
One method is i guess re-roasting coffee.
It says.."Be advised that the microwave packets currently distributed by an organazation called Smiles Coffee do not result in home-roasted coffee. The beans in the microwave pouches are already roasted when sold. All you do is heat them up"
The other method is using a cone called the Wave-Roast. you load the beans in a cone place them in a microwave and it rolls around. I guess it roasts very un evenly.
itinerant Senior Member Joined: 1 Sep 2005 Posts: 901 Location: Vancouver Expertise: I live coffee
Posted Tue Aug 8, 2006, 1:41am Subject: Re: Microwave Roasting?
It's hard to imagine that a microwave would be effective at roasting coffee. A microwave does not heat by adding thermal energy like a conventional oven. Microwaves cause water molecules to vibrate & generate heat. Foods with low water content do not microwave well. You will also notice that meat does not brown in a microwave, as the microwave never attains temperatures that a cooktop or oven does. So it's going to be hard to get a decent temperature profile to roast your coffee beans.
I suppose you could use a microwave to indirectly heat the beans. This is the idea behind a microwave popcorn type bowl. The bowl has embedded metal which heats to a higher temperature, then radiates heat to the popcorn (or bean mass). But this would still be marginal, at best.
Yirga Senior Member Joined: 3 Feb 2006 Posts: 659 Location: Big Bend Expertise: Just starting
Posted Tue Aug 8, 2006, 5:08am Subject: Re: Microwave Roasting?
DarkMajestic Said:
"Anybody have microwave oven coffee roasting experience they'd like to share? "
HOLY COOooooW !!! Four ounces of Brasil Santos up in smoke !! Two minutes with the beans in a glass bowl not a good method apparently !
A nice demo though of a microwave cooking from the inside out ... the beans in the center of the glass bowl were all VERY black ... made Starbuck's look light roasted ... filled the bloody house with smoke ... the fastest french roast in roasting history.
I suppose one could agitate the beans and reduce the power but not sure what good that will do .. could not hurt ofcourse .. the whole house stinks like burnt pop corn.
As a master roaster said to me " When you roast you are the master of your own fate ". I'm a bit stymied on this one ... What next ?
I'd say you're in the, agony of defeat, category! Four ounces in a glass bowl, eh? For how long? What was the dimension of the smallest thickness of beans?
I can tell you paint with the, broad stroke! Hold my beer and watch this! Outside, using a 12"-14" turntable MW with ~1200 W of power, load one pound of greens on the TT (~1" thick). With full power and timer set for 20 min., nuke for 3 min., pause, stir beans gently (several turns with a chopstick) then level beans with a flat object, continue nuking in the same fashion until ~20 min. or until color/oil sheen matches the profile you want. If you are filming yourself and want to sell it to, Jackass, just do like you mentioned you did before (or even longer) and the flames should melt down the MW and maybe even finish off with an explosion!
I already know the coffeegeek roasting mind set is to load beans, turn on a roasting device, then have the device turn itself off or time it for so many minutes and manually turn off the device. What I was hoping for was for maybe a few, out of the box, types who'd messed around with MW coffee roasting, survived it short of 3rd degree burns or death, and had gotten better results than I have, so far! Not, the case with your experience although you had the good sense to pull the plug before the fire and explosion!
For those who've never experimented with MW roasting on your own, my advice is not to try it as the result of my inquiry! Only those with a history of such dangerous undertakings need reply! Thanks! And stay, safe!
Yirga Senior Member Joined: 3 Feb 2006 Posts: 659 Location: Big Bend Expertise: Just starting
Posted Tue Aug 8, 2006, 5:32am Subject: Re: Microwave Roasting?
itinerant Said:
It's hard to imagine that a microwave would be effective at roasting coffee. A microwave does not heat by adding thermal energy like a conventional oven. Microwaves cause water molecules to vibrate & generate heat. Foods with low water content do not microwave well. You will also notice that meat does not brown in a microwave, as the microwave never attains temperatures that a cooktop or oven does. So it's going to be hard to get a decent temperature profile to roast your coffee beans.
I suppose you could use a microwave to indirectly heat the beans. This is the idea behind a microwave popcorn type bowl. The bowl has embedded metal which heats to a higher temperature, then radiates heat to the popcorn (or bean mass). But this would still be marginal, at best.
You'd be surprised how even MW's roast coffee in a max depth ~1 inch roasts, even without stirring much! Stirring around every 3 min. will help even roasting moreso, but I've only done it with one pound batches, so maybe smaller ones could get one into the fire and explosion twilight zone! Don't let me tempt you to try MW roasting if you've never done it on your own! I'm interested only in those who've done it already (and have lived through it -- still alive)!
Also, you've left out how oils absorb microwaves and generate heat, also! Your example of MW's not, browining, food is not a good one since food is never cooked like coffee is roasted. You ever eaten a steak cooked to the level of a coffee bean, in a MW oven? Hmmmmm? Steak, espresso?
Posted Tue Aug 8, 2006, 2:23pm Subject: Re: Microwave Roasting?
Last night I found a few Panama Organic Berlina Beans left in the bag. There appeared to be about enough for a couple double shots. Roasted in The Z&D this was OK coffee. I sure wasn't about to take a chance on ruining a lot of beans.
I got a glass bowl and dumped the beans into it. I used an old GE 700 Watt microwave oven. It did not come with a turntable. I have an old Nordic-ware windup turntable which I used.
I put the bowl on the turntable, set the machine for about ten minutes and started it. I had a wooden spoon in my hand for stirring. The default is full power (all 700 Watts of it). In about 1 minute 30 seconds I started getting about the loudest 1st cracks I ever heard. I opened the door and stirred, then started the machine at a lower power setting. I watch thru the glass with a big flashlight. Every minute i would stop and stir. I found it hard to keep the beans evenly spred on the bottom of the bowl so I abanded the spoon and grabbed my welding gloves. Periododically I would stop the machine and pick up the bowl and shake it. The beans seemed to be roasting very unevenly but I discovered that it was that chaff remained on some beans and was shed on others. After the cracks subsided (about 10 minutes) I just continued untill I thought the beans were dark enough. I never heard a second crack. I dumped the beans into a sauce pan and cooled them by dumping from one pan to another. By the way you may want to do this out side as the microwave does not have a catylitic converter.
This morning I pulled a double shot and actually drank it. It may have been as good as my first attempt in a poppery several years ago, but I'm not putting my Z&D or my HWP up for sale just yet.
The beans had rested about 6 hours when I tried them. I have enough left for at least one more double.
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