Home Coffee Roasting

[melkor]

I suppose I could, but since my vacuum is a roomba and I don't own a blow dryer I'd have to buy something. I'm thinking I'll build a stand for a box fan so it blows air up, and a screen bottomed box that will sit on the fan to hold the beans. I just need to get around to buying the fan.

[phaelon56]

One of the guys who posts regularly on the Sweet Maria's Home Roaster mailing list is now selling a stainless steel drum with internal vanes, ready for use on a rotisserie and gas grill but IMHO it's really pricey at $210

Ron Kyle's Roasting Drum

Ron's roasts 1/2 lb up to 4 lbs but I usually want to roast anywhere from 1/4 lb up to 1 lb. I'm limited to 1/2 lb with my Alp and it's tricky to roast smaller amounts as the roasting time changes dramatically. I have tried adding ceramic pie weights to a smaller batch so that total weight is still 1/2 lb and it seems to work well. When doing binary espresso blends, it's really helpful to be able to roast smaller amounts (binary blend are those in which beans of slower or faster roasting varieties are roasted separately and then blended, rather than just roasting them all together). I'm a solo user and 1/2 lb seems to be about the amount I can use up in 5 - 10 days before beans start to go flat.

Melkor's design looks like a far better choice for us smaller quantity roasters, not to mention the pasrts are avilable cheaply enough. It's worth noting that the internal vanes on Melkor's drum (they appear to be made of angle iron?) are crucial in the design - they provide agitation for the beans. Now that I will finally be in a house of my own rather than an apartment I think I'll try this.

[MGLloyd]

Noting that the drum is made of wire mesh pencil cups from an office supply store, my old chemistry and healthcare background prompts me to ask if you know what the mesh and the coating is made of?

My only concern is if the materials are food-safe and most particularly if the coating of the wire mesh does not degrade with heat and agitation to release toxic byproducts.

[MGLloyd]

Noting that the drum is made of wire mesh pencil cups from an office supply store, my old chemistry and healthcare background prompts me to ask if you know what the mesh and the coating is made of?

My only concern is if the materials are food-safe and most particularly if the coating of the wire mesh does not degrade with heat and agitation to release toxic byproducts which would end up in the coffee and subsequently in you.

[melkor]

The mesh is powdercoated aluminum, I tried burning the coating off but it wasn't interested in coming off so my clearly questionable scientific conclusion is that it's safe. I've been using one of the cups for the past year or so and its in the same shape as the second cup I added six or so batches ago.

[Msk]

Well, you all have done it to me. I have gone ahead and ordered a Freshroast and a couple of different types of beans. I am going to stick with my drip maker and crappy grinder for the moment, but if my drip coffee improves with the fresh roasted beans like I expect it to, I will likely add a press pot and Burr grinder to equation.

Thanks to all for the information and education.

Msk

[melkor]

Well, you all have done it to me. I have gone ahead and ordered a Freshroast and a couple of different types of beans. I am going to stick with my drip maker and crappy grinder for the moment, but if my drip coffee improves with the fresh roasted beans like I expect it to, I will likely add a press pot and Burr grinder to equation.

Thanks to all for the information and education.

Msk

Congrats! Let us know how things go.

[MGLloyd]

Over on coffeegeek.com, there has been a lot of experimentation lately to resurrect an older method of coffee roasting. Yes, you too can roast your own coffee quickly and cheaply with some very basic tools: a heatgun and a steel dogbowl. This method is probably the cheapest method available to the homeroasting community to produce significant quantities in a short amount of time.

I have written a primer for the coffeegeek community and also post it here for the eGullet community. Unfortunately, the pretty pictures did not paste over, so this is the text only version. This does presume some basic roasting experience, such as first crack and the like. If you don't have that experience, try it anyway and see how it works for you.

If anyone has any questions or comments, please post here and I will be happy to help. Happy roasting!

Regards,

Michael Lloyd

__________________________________________________

__________________________________________________

Heatgun\dogbowl roasting 101

Pros: Entry costs are low

Excellent control over roast

Capable of large batch sizes (5 to 16 oz.)

Necessary equipment is simple and robust

Easy to monitor the roast

Able to immediately halt roast at any point

Can roast 2-3 lbs. per hour

Even roasting

Quality of results dependent on operator technique

Rapid learning curve

Allows user to determine a range of fluid bed (hot air) to drum roasting conditions and results by varying airflow and length of roast

Easy to roast small amounts for blending

Cons: Must be done outside due to smoke and chaff

Not a ‘set and forget’ method

More difficult to precisely reproduce results at every roast

Requires separate cooling method

Difficult to monitor roast temperature

Requires holding the heatgun and stirring for 10-15 minutes

Quality of results dependent on operator technique

Basic equipment needed: Heatgun

Roasting vessel

Stirring utensil

Metal colander or other cooling method

The earliest mentions of using a heatgun and a roasting vessel to roast coffee go back to the early 1990’s on the Net and in the alt.coffee Usenet newsgroup. Attaching a roasting chamber filled with coffee beans to a heatgun muzzle goes back even further. This technique, developed by Michael Sivetz to roast coffee samples, uses the Wagner HT 775/Milwaukee 750 heatgun still available today.

Since the last quarter of 2003, this older method has become more popular. Why the sudden upsurge in interest over the heatgun? Theories abound, but one possible reason is a backlash against expensive and unreliable roasting appliances that often do not work well out of the box and can require juryrigging to obtain good results. By contrast, the heatgun method has low entry costs and the equipment is simple and robust, producing a significant throughput of a quality roast. It combines elements of both an air fluid-bed and conduction roast. Roast times can be controlled to produce a quicker, brighter roast or a slower, fuller roast. Thus one simple and inexpensive equipment setup can replicate either an air roast or drum roast. This method is probably the cheapest means of producing significant batch sizes at nominal costs. The closest competitors are the HotTop at $ 600 and roasting nine ounces, the AlpenRost at $ 290 and roasting eight ounces and BBQ grill roasting drums at $ 125-210 and capable of roasting up to four pounds on your existing gas BBQ grill.

Through the efforts of an intrepid group of experimenters at Coffeegeek.com, to include Martin Lipton, Jim Liedeka and Michael Lloyd as the early adopters, the heatgun method has recently undergone a great deal of refinement and some recommendations are presented here on equipment and technique. Michael Lloyd is the originator and author of this primer and any mistakes are entirely his. As with all methods of coffee roasting, the heatgun method involves high temperatures and care should be taken to avoid personal injury and property damage.

Equipment

The heatgun

The most important piece of equipment for this method is the heatgun. For those unsure of what a heatgun is, think of a handheld hair dryer capable of reaching temperatures of 250-1100 degrees and powered by electricity. Heatguns are commonly used for stripping paint, bending plastic, plumbing, electronics assembly, arts and crafts and can be found in the paint department of most hardware stores. Heatgun prices typically range from $ 25 for light-duty home use models to $ 175 for industrial models.

Work is still ongoing to find which models of heatgun are suitable for coffee roasting. Preliminary data from user reports indicates that the heatgun should be capable of at least 500 degrees Fahrenheit and have an air velocity of at least 14 cubic feet per minute (CFM) in order to achieve sufficient heat transfer to reach roasting temperatures. The higher the wattage of the heatgun, the more efficient it is for roasting. Some users report that an adjustable temperature allows them to better ramp the roasts. A cool setting may be useful to both cool the beans and prolong the life of the heating element.

At this time, the following models have been used with success:

Makita 1100

250-1100 degrees

8-14 CFM

1500 watts

$ 75

Wagner HT775/Milwaukee 750

500-750 degrees

19-23 CFM

1680 watts

$ 60

Wagner HT 1000

750-1000 degrees

CFM unknown

1200 watts

$ 30

PitBull CHIGH0012

700-920 degrees

CFM unknown

1500 watts

$ 15

Milwaukee 1220HS

750-1200 degrees

CFM unknown

1200 watts

$ 25

One user felt that the Porter-Cable heavy duty heatgun had too high an air velocity (27 CFM) which blew too many beans out of the roasting vessel.

The roasting vessel

The original roasting vessel used in this method is a stainless steel dogbowl, but other bowls and containers are used as well. Other potential roasting vessels are mixing bowls, saucepans or a round cake pan.

The most commonly-used type of dogbowl (the classic) looks like this in cross-section: \_____/. Here are some pictures of classic dogbowls:

Another type of dogbowl (the non-tip or non-skid version) looks like this in cross-section: /\_______/\. This type of dogbowl is recommended if you use a BBQ grill as a supplemental heat source. This is described later in the primer. Here is a picture of a non-tip\non-skid dogbowl:

A key element of success in this roasting method is to match the size of the vessel with the batch size. If the vessel is too small, the depth of the bean mass will be too great, and an uneven roast and spillage will occur. If the vessel is too large, the depth of the bean mass will be too shallow, and the surface area of the bean mass too large, leading to difficulty in reaching roasting temperatures, overly-long roasts and uneven roasts. There is a ‘sweet spot’ of bean mass surface area and depth that will retain heat to sustain an endothermic reaction and reach first and second crack in an appropriate amount of time. No matter what diameter is the roasting vessel, it should be at least 2.5-3.0 inches deep to avoid blowing the beans out of the vessel. The recommended shape is round, so that beans do not get trapped into corners and roast unevenly.

Recommended sizes depend upon the batch size and the diameter and depth of the roasting vessel. A good rule of thumb would be to use a vessel with a capacity at least four times the volume of green beans used. Using a classic dogbowl as a typical example, a 32 oz. bowl accommodates one cup of beans by volume; a 64 oz. bowl accommodates two cups; and a 96 oz. bowl accommodates three cups. Although weight per cup is only approximate and depends upon the specific bean type, a good approximation is one level cup by volume weighs on average 5-5.3 oz., two cups by volume weighs on average 10-11 oz., and three cups by volume weighs on average 15-16 oz.

The material of the vessel is important too. It has to be heat-resistant, have a smooth interior surface, easy to clean and not subtract too much thermal energy from the bean mass. Using cast-iron, heavy-gauge metal cookware or cookware with a clad or sandwich metal-core bottom can create hot and cold spots. The mass of the metal acts as a thermal sponge to absorb heat unevenly resulting in prolonged and uneven roasts. It is not known at this time if a glass, Pyrex or ceramic vessel would give satisfactory results or be safe to use. Stainless or carbon steel or aluminum would be good materials for a roasting vessel. If you are using a saucepan or cake pan, make sure the pan is uncoated, since some non-stick materials will not tolerate the high heat of a heatgun and may release toxic fumes.

For all of these reasons, and cost, a stainless steel dogbowl, mixing bowl, cake pan or saucepan is recommended. These items may already be in your home or can be purchased very cheaply at thrift, discount, pet or department stores. As an example, at a national chain of pet stores, a 32 oz. dogbowl sold for $ 5.49, a 64 oz. dogbowl sold for $ 6.99 and a 96 oz. dogbowl sold for $ 8.99.

Stirring utensil

A heatproof stirring utensil can be used to stir the bean mass throughout the roast. A long wooden or metal spoon or length of doweling works well.

Technique

A sample roast is presented here using a Wagner HT 775 heatgun and a 64 oz. classic dogbowl. Of course, other types of heatguns and roasting vessels can work equally well. This description presumes you have some experience with roasting.

Begin by assembling all the equipment and pour two cups (by volume, approximately 10-11 oz. by weight) green coffee beans into the bowl.

The sample roast shown here is Liquid Amber from SweetMaria’s.

Outside the house or in a covered and very well-ventilated area (this method does produce copious amounts of chaff and roasting smoke), put the dogbowl on a heatproof surface, start up the heatgun on the low setting (side louvers open at 500 degrees), and holding the muzzle of the gun approximately 1.0 -1.5 inches from the surface of the beans, begin playing the heated air evenly over the surface of the beans.  

If the airflow of the heatgun is not sufficient to stir the beans, then periodically stir the beans with a heatproof utensil while continuing to play the heatgun over the surface of the beans.  After approximately four to six minutes, the beans will begin to smell grassy and turn a light tan in color.  

Close the side louvers of the heatgun (changing the temperature to 750 degrees) and move the heatgun muzzle to within approximately 0.5 to 1.0 inches from the surface of the beans and continue playing the heated air over the surface of the bean mass.  As the roast progresses and the beans become lighter, you will often be able to stir the beans solely by the airflow of the heatgun.  Be sure to stir the beans throughout the roast.  Do not be alarmed if chaff blows off the surface of the beans and catches fire.  It will quickly self-extinguish.  Move the muzzle closer or further from the surface of the bean mass as dictated by how fast the roast is progressing.

At approximately 8 minutes or so, you should reach first crack, and second crack at about 9 minutes.   When the roast is complete to your liking, quickly dump the beans into a metal colander or cool the beans in the usual fashion.  This technique should give you approximately three cups by volume of roasted beans.  If the heatgun has a 'cool' setting, turn the heatgun to cool and let it run for a few minutes until it is cool to the touch.  This will extend the life of the heating element in the heatgun.  

The time to complete a roast also varies by volume; a one cup roast typically takes about seven minutes, a two cup roast typically takes about ten minutes and a three cup roast typically takes about 13-15 minutes (these times do not include cooling).  These times are also a function of this author’s roasting experience and preference: I like a slower and ramped roast to replicate a drum roast profile.  Other people who prefer a brighter roast, like those produced by poppers or the FreshRoast, may like to do a two cup roast in five or six minutes.  Decaf coffees will generally roast in less time for the same volume of coffee.

The total time is very dependent on volume, heatgun used, the roasting vessel used, ambient temperature and operator technique.  If you are roasting in very cold temperatures, the roast time may be prolonged or you may want to put the roasting vessel into a heatproof box or other container to help retain the heat. The best guide to the roasting process will be your eyes and ears as you monitor the roast.

Another technique adopted by some users is to use a gas-fueled BBQ grill to serve as another source of heat during the roast. A non-skid/non-tip dogbowl is commonly used since the skirt acts to retain heat under the bowl surface. The BBQ is lit, generally set on medium and allowed to pre-heat for a few minutes. The dogbowl with beans is set on the grill and the heatgun is used in the typical fashion. Proponents of this method feel that the grill allows for a more controlled roast and more reproducible results.

Conclusion:

Heatgun/dogbowl roasting is a quick, simple, and inexpensive way to produce quality roasted coffee. The entry costs are low and the method very forgiving. This is one of the most cost-effective ways to roast significant quantities of coffee for home use.

Further resources:

The Home Roasting Talk forum at www.coffeegeek.com and “Home Coffee Roasting” by Kenneth Davids are excellent sources of information on roasting coffee in general.

Contact the author:

If you have any suggestions or changes to this document, please contact the author, Michael Lloyd, at millcreek2010@yahoo.com.

Edited January 25, 2004 by MGLloyd (log)

[fresco]

To ease my way into this, I've been roasting beans (a combination of Ethiopian and Colombian, which is what's available where I shop) in a cast iron skillet, and have been pleased with the results.

I've never timed this, but it doesn't seem to take more than about 10 minutes, with the gas turned off about three-quarters of the way through. And I roast enough to last three or four days at a time.

Aside from convenience, what would be the advantages, if any, of buying an electric roaster? Also, any roasting tips/recommendations greatly appreciated.

[MsMelkor]

We used to roast with a Hearthware electric roaster, but it roasts really quickly, you can only roast 3 oz at a time, and you have very little control over the roasting process. So Melkor made a rotisserie roaster that works with our gas grill. We have infinite control over nearly every variable (including how long it takes) and we can roast much more at a time (the roasted beans fill a quart mason jar). We buy our beans from Sweet Maria's - they have a great selection and lots of information about roasting coffee. Of course, there's also Coffee Geek for roasting discussions.

[slkinsey]

Wait a while and get the new Hearthware iRoast. You can change the roast profile, timing, etc. I have never found the Hearthware Precision's small capacity problematic, because I find that I can roast all the beans I use in a typical week in three "sessions" and I prefer to drink coffee from beans <1 week old.

[phaelon56]

Getting an electric drum style roaster or an electric fluid bed (aka hot air) roaster will quite possibly add a convenience factor and if you ahve the right model, might let you use a longer roast time, which typically creates a mellower flavor profile. Simple hot air roasters typically have about a f to 6 minute maxiumum roast tiem and deliver a somewhat bright finish to the beans. Some folks prefer this, especially for particular varietals. Others among us prefer the flavor profile less of slower longer roasts, particularly for espresso blends.

Chaff removal is often simplified with commercial home roasting units but if you're satsified with the skillet method, it's not terribly inconvenient for you and the smoke/chaff is not an issue - chances are you wont see significantly better results from other methods.

Soem of the absolute best coffee I have ever consumed was in Ethiopian restaurants when they do the Coffee Ceremony. They typically roast it at the time you order the coffee and do it in a beat up old saucepan on the kitchen stove.

[MGLloyd]

Read the heatgun/dogbowl coffee roasting primer elsewhere in this forum, or for a version with pictures, go to Heatgun/dogbowl primer. This is an excellent method that you may want to investigate.

[bucktown_boffo]

consider getting an old popcorn popper. there's a wealth of information online about home roasting with these. i just got one last week and it works great. only certain models are safe for home roasting -- this has to do with the placement of the heating vents so that the chaff doesn't get in and start a fire -- but they are easy to find and buy. there are also modifications you can make to the poppers to improve the quality of the roasting. i got a modified west bend air poppery II off of ebay. definitely cheaper than a gourmet home roaster model!

[fresco]

Read the heatgun/dogbowl coffee roasting primer elsewhere in this forum, or for a version with pictures, go to Heatgun/dogbowl primer.  This is an excellent method that you may want to investigate.

I have tried the heatgun method after reading about it here, but, and it's probably because of a lack of patience, I found a skillet works better for me.

[BobL]

I've been using an Alpenrost for a couple of years now and after the learning curve, I've been roasting a pound or more a week. It's fairly easy to use and clean, the results are very good. The cost is high.

[phaelon56]

A recent thread discussing the new Hearthware I-Roast had many tangential discussions arising - most of them related to general issues surrounding home roasting of coffee beans.

We have lots of home roasting expertise weighing in on this forum regularly - let's share some ideas, opinions and experiences.

Some worthwhile discussion points, sure to be expanded in this thread, might include:

• * Why do you roast your own coffee - is it cheaper, better or both?
  * What technique or machine is the best or most convenient?
  * Where do I get the green coffee beans?
  * What about smoke and mess - can I do this indoors?
  * Does it take lots of skill and also time to gain enough experience to produce good results?
  * My time is valuable (because I'm soooo important ) - is it really worth doing?
  

[MGLloyd]

* My time is valuable (because I'm soooo  important      ) - is it really worth doing?

←

Yes.

[scubadoo97]

Why do you roast your own coffee - is it cheaper, better or both? Both

What technique or machine is the best or most convenient? I use a heatgun/bowl method, thanks to MGLloyd and other heatgun mavericks

Where do I get the green coffee beans? There are many green bean sources around. I get my beans from the greencoffeecoop. Good coffee, good selection and good people!

What about smoke and mess - can I do this indoors? unless you have a commercial grade high CFM hood I would do it out doors.

Does it take lots of skill and also time to gain enough experience to produce good results? Anyone can do it. I roast a cup of green beans in about 10 min. and may spend 30-40 min a week on my coffee roasting.

My time is valuable (because I'm soooo important ) - is it really worth doing? Only if drinking awesome fresh roasted coffee is important to you.

Just do it!

[BrentKulman]

My wife is very particular about her AM coffee. Each morning, she grinds her Starbuck's French Roast beans (from Costco) in her Krups Fast Touch Grinder and pours the contents (I'm guessing about 6 teaspoons, but I could be off) into her Bodum french press. Her morning cup is probably about 12 oz.

I have to say that the coffee this produces is extremely muddy and bitter, with a fair amount of sediment at the bottom of the cup. But that's the way she likes it. I have bought her all kinds of beans but nothing satisfies her like Starbuck's French Roast.

I have been reading through the home roasting threads and am interested in buying her a home roasting system for her birthday. But I find myself somewhat confused and concerned that the end result will not be to her liking.

So, given what I have told you about her preferences, should I even consider introducing her to home roasting? If so, what equipment should I get her? From the research I have done, I don't think that French Roast is a type of bean but perhaps it is a style of roasting. Help me understand all this better as I don't generally drink coffee in the morning and this would be entirely her domain.

[hopkin]

Start by finding some better beans. From what you are using now it can only get better. Way better. Find a local roaster and get some fresh roasted beans.

French Roast is roast colour. Very dark "roasted" flavour, all of the more subtle "coffee" flavour have been roasted out. Try a medium-dark roast.

Then concentrate on brewing. press pot? coffeegeek guide to french press. your coffee will be very pleasant and aromatic, no bitterness. You might even like it.

[bigbear]

At the risk of ruining a birthday surprise, I would ask her if she is interested in trying the home roasting process and all it entails. You could wind up with another appliance, in a cardboard box, in a cabinet, somewhere.

[Abra]

We have a Fresh Roast from Sweet Maria's and like it a lot. It makes small batches, so you can do a lot of experimenting. Their green beans are super, too. One caution is that you either have to roast outdoors, or under a really good kitchen hood, as it creates a lot of smoke. But if that's no problem, roast on!

[missmaia]

My wife is very particular about her AM coffee.  I have to say that the coffee this produces is extremely muddy and bitter, with a fair amount of sediment at the bottom of the cup.  But that's the way she likes it.  I have bought her all kinds of beans but nothing satisfies her like Starbuck's French Roast.

←

Having said this, I think she may be pretty happy with what she likes. Instead of buying her a biggish appliance that *will* create a lot of smoke and carbon (being as French and Italian ~ the roast colors~ are as dark as it gets) why don't you instead cater to her likes? I'd start with a fancy new press ( I think Bonjour makes a nifty copper one), or maybe cup and saucer set with a tray, so she can carry it into whichever room she likes to take her coffee. While you're at it, you could also include a gift certificate to a local roastery/cafe... maybe she'll find another kind of coffee she likes that's local.

[Merritt]

We have a Fresh Roast from Sweet Maria's and like it a lot.  It makes small batches, so you can do a lot of experimenting.  Their green beans are super, too.  One caution is that you either have to roast outdoors, or under a really good kitchen hood, as it creates a lot of smoke.  But if that's no problem, roast on!

←

Can you recomend a specific model? I was on their website and I found quite a lot to choose from. I am interested in small amount roasting...roast the day-before for the next day, etc.

Thanks in adavance for any help.