A Brief and Biased History of Roasting
Some time around 1200 AD, coffee was roasted in a firepit in the region of Ras al-Khaimah along the Arabian Gulf. It's the oldest roasted coffee bean ever found, and predates the previous estimate by 200 years. Since it was discovered far from the areas of Harar in Ethiopia where coffee was first discovered growing wild, it is clear that the dried seeds from the plant were traded between Arabic peoples ... and its influence spread rapidly both among the religious who first used coffee to stay awake during long prayer rituals and the common folk.
The coffee cherry was eaten directly for its sweet and stimulating pulp. The pulp was also fermented from the seed and used to create the beverage kishir. But what the heck could anyone do with those seeds? I suppose the impetus to find a use for every part of every food item, and the knowledge that dense or unpleasant seeds could be put in the ashes of a fire to soften them or reduce unpleasant flavors led to the discovery that roasted coffee was indeed palatable. And infusing a beverage from the crushed roasted seed was a way to extract the flavor and avoid the woody residue of the bean in the mouth (try eating 20-30 roasted beans ... you'll see what I mean!)
Roasting was always part of the coffee service ritual since the green dried seed was easy to store, and did not deteriorate over time. It was dense and could not be crushed in transit. Since all the coffee was essentially burned to a crisp in a flat pan with a long handle that was held over the fire, it was indeed fragile after roasting. It made sense to roast coffee just for the group of people who were about to indulge in it... and it was not until the late 1700's that larger scale roasting apparatus was required.
The first commercial roasters were often arranged in a battery, set into brick kilns that would hold and contain heat from the wood-fired source. Cast iron drum roasters were also used. In either case these roasters, like the humble pan held over the fire, relied on conductive heat transfer almost exclusively to roast the coffee. The coffee gained heat by its direct contact with the hot metal surfaces of the roaster.
Roasting of this type offered little control. Coffee was often roasted quite dark, and was very uneven in the degree of roast from bean to bean, since all the coffee could not possibly have the same amount of contact with the hot metal surfaces of the roaster.
Jabez Burns invented a different type of roaster in the 1870's. It used a perforated metal drum that allowed the chaff to separate from the coffee, and convective air flows to circulate around the batch of beans. The volume of hot convective air heated the coffee, and some supplementary heat was provided by radiant heat from the burners and hot metal of the roaster. Coffee could be roasted evenly, and also much lighter. The benefit of roasting lighter was that the coffee lost less weight in the roasting process, and more salable product emerged from the drum than was possible before.
The new convective system also allowed a longer roast time and better control of the degree of roast. An experienced operator could produce the same roast time and time again, effectively dumping the batch into a stationary cooling bin with an agitator, whereas previous roasters dumped coffee into moving cooling bins wheeled about the factory with no agitation.
Not a lot has changed from that time until the present. Small batch drum coffee roasters have either solid drums with control of convective air flow passing through them, or perforated drums. No roaster relies primarily on conduction as the heat source. For some the romance and craft of roasting is in the simple equipment we use. There are better flame controls and thermocoupled temperature monitoring, but basically the progression of the roast is built into the equipment, determined by the metals used, the burners installed, and the cooling system. Sure, I could scorch a batch of coffee in 4 minutes in my 12 Kilo Diedrich roaster, or bake it for 40 minutes, but my preferred roast time/temperatures (around 11-12.5 minutes for a City Roast) offer little choice in exactly how the coffee will reach that exact roast degree. It just so happens to be quite good though.
What's this all about? Why have I chosen to write all this in a home roasting newsletter? It's to let you know that roasting coffee is still a very simple act, perhaps far behind the technological possibilities of the present. Roasting is a set of extremely complex reactions induced by temperature that involve a dizzying array of beginning, middle and final compounds whose exact interrelationship is difficult to specify. At center stage are the Malliard reactions that involve many of the key coffee flavors as well as the browning color of the coffee. A perfect roast technology would maximize all the key components needed for roast reactions such as the Malliard during the stage in which the coffee gains heat, ensure that the roast reactions occur properly, and thus result in the that the maximum quantity of flavor compounds after the roast reactions have concluded. We are a long way from this kind of roast apparatus!
What most shop roasters are doing is roasting to a specific degree for a specific coffee ... the "art" of roasting is determining that exact degree and dumping the batch into the cooling bin in then 15 second window that the coffee is at its target point. And that's what the home roaster is doing too. The air or drum roasters we use at home have the basic roast curve set, and we try to roast to that exact time and temperature that we prefer, either to maximize the "original flavors" in the coffee, or to roast it darker and imbue it with "roast flavors".
I might be understating the difficulty and skill of professional roasting here, summing it up too briefly. But I want home roasters to understand that just because a coffee is professionally roasted, means very little. The skill in professional roasting does not lay in the part of the shop where the roasting machine sits. It is over at the table where the roaster cups the samples, carefully chooses the green coffee to buy, tests it at varying degrees of roast, and finds the best way to bring out the most in the coffee's "original flavors" or to create a stylized darker roast of it.
Yes, new technology that makes true "profile roasting" possible may change this ... a roaster that can determine bean temperature points in the roast process, perhaps determining key roast chemicals like trigonelline or chlorogenic acids on the fly, and making adjustments to allow the operator great control of the process. Until then, we have our own sensible palates to guide us. With that, we can enjoy great coffee. Without it, big batch or small, we're just burning a dried seed.
Sweet Maria's Green Coffee Offerings on 5/23/00
Coffee is a crop; it comes and goes! Our web page always has the latest list of offerings: www.sweetmarias.com
Central American 1 lb 2 lb 5 lb
Costa Rican Dota Conquistador 99-00 $5.60 $10.64 $24.36
Costa Rican Tarrazu La Minita 99-00 $6.95 $13.21 $30.23
Costa Rican La Pastora Tarrazu 99-00 $4.80 $9.12 $20.88
Guat. Organic-FairTrd. -El Quiche $5.50 $10.45 $23.93
Guatemala Huehuetenango -Dos Lagos $4.70 $8.93 $20.45
Guatemala Huehuetenango -Catinil $4.80 $9.12 $20.88
Guatemala Oriente -Tres Marias $4.75 $9.03 $20.66
Mexican Organic Pluma -Loxicha $5.00 $9.50 $21.75
Mexican San Pablo Tres Flechas $4.70 $8.93 $20.45
Nicaraguan SHG Gavilan Estate $4.60 $8.74 $20.01
Nicaraguan SHG La Illusion $4.70 $8.93 $20.45
Panama Hartmann Songbird 99-00 $4.75 $9.03 $20.66
Panama Lerida Estate 99-00 $4.90 $9.31 $21.32
South American 1 lb 2 lb 5 lb
Brazil Cerrado-Monte Carmelo $4.40 $8.36 $19.14
Brazil Cerrado-Oberon 17-18 $4.70 $8.93 $20.45
Brazil Serra Negra 17-18 $4.55 $8.65 $19.79
Colombian Ibague Nevado Supremo $4.80 $9.12 $20.88
Peru SHG Organic -Cuzco $4.95 $9.41 $21.53
African- Arabian 1 lb 2 lb 5 lb
Ethiopian Djimmah Gr 5 $4.80 $9.12 $20.88
Ethiopian Harar Gr5 Horse $5.50 $10.45 $23.93
Ethiopian Sidamo Gr.5 99-00 $5.00 $9.50 $21.75
Ethiopian Yirgacheffe Gr2 $5.50 $10.45 $23.93
Kenya AB Main Crop 98-99 $5.20 $9.88 $22.62
Kenya AA Kiunyu Estate 99-00 $5.80 $11.02 $25.23
Kenya AA Nyanja Estate 99-00 $5.60 $10.64 $24.36
Tanzanian Peaberry 99-00 $5.20 $9.88 $22.62
Yemen Mokha Ismaili $7.80 $14.82 $33.93
Yemen Mokha Mattari Al-Haj $7.00 $13.30 $30.45
Yemen Mokha Raimi 99-00 $6.90 $13.11 $30.02
Yemen Mokha Sana'ani -Saihi $6.90 $13.11 $30.02
Zimbabwe AAA Pinnacle $5.60 $10.64 $24.36
Indonesian- Indian 1 lb 2 lb 5 lb
Indian Monsooned Malabar AA $5.50 $10.45 $23.93
Indian -Pearl Mountain Estate $4.90 $9.31 $21.32
Java Aged Old Brown $6.20 $11.78 $26.97
Java Gvt. Estate -Kayumas $5.10 $9.69 $22.19
Myanmar Arabica -Rubyland $3.50 $6.65 $15.23
Papua New Guinea A Org-Shade $5.20 $9.88 $22.62
Papua New Guinea Purosa AA $5.60 $10.64 $24.36
Sulawesi Toraja-Boengie Fat Bean $5.70 $10.83 $24.80
Sulawesi Toraja Gr.1 99-00 $4.80 $9.12 $20.88
Sulawesi Rantapao (Monsooned) $6.10 $11.59 $26.54
Sumatra Mandheling Gr1 DP $5.00 $9.50 $21.75
Sumatra Mandheling-Triple Pick $5.20 $9.88 $22.62
Sumatra Organic Gayo Mtn.Gr1 $5.50 $10.45 $23.93
Sumatra Organic Gayoland.Gr1 $5.50 $10.45 $23.93
Sumatra Blue Lintong Gr1 $5.30 $10.07 $23.06
Timor Grade 1 -Aifu $5.00 $9.50 $21.75
Islands- Blends -Etc. 1 lb 2 lb 5 lb
Hawaii Kona Greenwell XtraFancy $15.20 $28.88 $66.12
Hawaii Kona- MorningGlory Peaberry $16.85 $32.02 $73.30
Isle of Saint Helena $21.20 $40.28 $92.22
SM's Moka Kadir Blend $5.80 $11.02 $25.23
SM's Espresso Monkey Blend $5.00 $9.50 $21.75
Sweet Maria's Fr.RoastBlend $5.50 $10.45 $23.93
Malabar Gold Espresso Blend $6.00 $11.40 $26.10
Decafs 1 lb 2 lb 5 lb
Brazil Santos SWP Decaf $5.40 $10.26 $23.49
Colombian Natural Decaf $5.20 $9.88 $22.62
Costa Rican SHB SWP Decaf $5.70 $10.83 $24.80
Ethiopian Sidamo Co2 Decaf $6.20 $11.78 $26.97
IndonesianOrg.KomodoBlend SWP D $6.20 $11.78 $26.97
MexicanEsmeralda Natural D $4.70 $8.93 $20.45
Papua New Guinea Org SWP D $6.00 $11.40 $26.10
Sumatra Org.GayoMtn SWP Decaf $6.30 $11.97 $27.41
Premium Robustas 1 lb 2 lb 5 lb
Indian Kaapi Royale Robusta $5.00 $9.50 $21.75
Indian Monsooned Robusta AA $5.20 $9.88 $22.62
PapuaNewGuinea Washed Robusta $3.90 $7.41 $16.97
Sweet Maria's Coffee Roastery
9 E. 2nd Ave. * Columbus Ohio 43201
ph/fx:614 294 1816 / 888.876 5917