- Roasting is fun. It's as easy as you want to make it, or as exacting and technical as you care to be. Pay attention to the process, especially toward the end of the roast. The roasting process unfolds slowly at first as the coffee loses moisture and turns to a yellow, then tan color. But later in the roast, each few seconds that pass have a large influence on the flavors in the cup. You can roast too dark, burn the coffee and damage the roaster, so always be present while the machine is in use!
- Coffee roasting produces a wonderful fragrance, unobtrusive with light roasts but smokier if you roast dark. Operating any type of stove hood fan helps if the smoke is too intense for you. You can roast on a porch or near a partially open window weather permitting. But cold temperatures will severely effect the roast, and may make the roast stall completely.
- Roasting produces chaff. Chaff is a fine skin that detaches from the bean as your roast is agitated. Your roaster collects the chaff, but expect a little to escape. Empty the chaff collector between every roast and brush it out to get perfectly consistent results. For safety, the roaster will not start if the roast chamber is not rotated into the locked position by turning the roast chamber clockwise on the base.
- Built-up coffee oils in the roaster are of no real consequence until they impede visibility or become a fire hazard. (In fact, a professional drum roaster requires hours of roasting initially to properly "season" the drum.) Empty chaff between each roast- and SOAK THE ENTIRE CHAFF COLLECTOR ASSEMBLY IN DEGREASER PERIODICALLY TO REMOVE BUILT UP OILS- REDUCED AIR FLOW CAN OVER HEAT ANY ROASTER AND KILL IT.
- Batch size is critical in any roast process; if the amount of coffee you put into the roaster varies, the roast will vary too. Ideally, it is best to roast by weight, not volume. We currently offer an accurate digital scale for this purpose. I have been using 130 to 150 grams per batch or basically 6 ounces by volume. This is not the same as what Hearthware recommends! So you might try both and see what you like.
- The i-Roast comes with two pre-set programs. USE THE PRESETS FIRST as you get to know the machine. You can customize the roast times on either pre-set - You can add time to a roast that seems to be finishing too light (you can only add time in Stage 3 of the process), and of course you can always hit to COOL button to stop a roast early. To get the exact degree of roast, it is always preferred to manually stop the roast (by hitting the Cool button) when you see, hear & smell the signs of that roast you prefer! Trust your ears and senses to get best results. Start out by setting long roast times and stopping the roast manually to get a feel for how the roaster is operating on your specific household voltage. (Yes, it makes a difference! Household voltage varies greatly from 106 to 130 in the U.S.)
- I prefer to dump the coffee into a stainless mesh colander after the cooling cycle completes, just to get the coffee away from the warm metal/glass surfaces. When the coffee is room temp. I transfer it to canning jars. Coffee is better after 4 hours of "resting", which allows the CO2 to de-gas from the coffee. It is at its flavor peak at 12-72 hours. When you open the jar, you will know what I mean!
- This machine is for HOME USE ONLY - Hearthware makes that very clear in the instructions. You have to also wait for the roaster to cool between batches - the manual says at least 20 minutes - though some customers have told us longer.
Program Tips for the Hearthware i-Roast ver.6/04
Understanding the Program Temperatures and the Onboard Thermometer Readings: The i-Roast is truly a next-generation home coffee roaster because you can create your own roast programs. Use the pre-sets to get used to the machine function, and remember that you can customize the overall roast time on each of the pre-sets. To find out how to use the custom program function and to adjust the roast times on the pre-sets, see the i-Roast manual.
There's a trick to using the custom program: the temperatures you program are not the temperatures you are going to read on the thermometer during the roast. This is going to take some getting used to, but after a few trials you will see the correlation. The actual onboard thermo temperature seems to be about 40-50 degrees lower than what you program. So when you set warm-up max temperature and you want to see 380, you will have to program in 430, roughly. But the other factor is the air flow pattern - if the roaster uses a high velocity air flow to maintain the program temperature you choose, it will tend to lower the overall roast chamber temperature. I like this for the first stage because it aids in even roast development. In fact, the i-Roast is the most even roaster I have seen for the early warmup stages, aside from $4000 professional sample roasters! I am still playing with the programs and seeing how different time & temperature combinations affect the roasters behavior in terms of onboard temperature readings and air movement.
***Please note - It seems that with later versions of the i-Roast 2 the on-board temperature and the programmed temperatures more closely match. So the information about seeing a temperature differential may not apply.
In general, programmed temperatures of 320-400 degrees are good for your warmup period and are not going to get the coffee into the first crack. Settings of 450-470 degrees are going to slowly get the coffee into the first crack range. (First crack occurs with onboard thermometer readings of around 375-380 on my test roaster). If you can avoid using the highest temperatures, 480 to 485, do so ... but if you need them to get the kind of roast you are looking for then they are there to use! If these conflicting temperature settings/readings seems odd, remember that the numbers are not the important thing ... what you want is for a coffee seed to progress evenly and steadily through the roast stages, not too fast or too slow. The i-Roast does that extremely well with the pre-sets, and with the custom programs you can truly get one-of-a-kind roast results. Don't program a roast that has the seed advance to a stage of roast (such as the medium brown color the coffee achieves just before 1st crack) and then just stall there for a long period of time. Using your program, keep the coffee moving, slowly and steadily, through the roast stages. With darker roasts, try to have a "controlled" end of roast, which is indicated by a defined pause between the end of the "first crack" and the beginning of the "second crack." (Another indicator is a slow and controlled sound of second crack, not a super-rapid, out-of-control snapping.)
What you are doing with the programmed temperatures is essentially lowering the fan speed so that less air moves past the coffee and it gets hotter as the roast progresses. A slower fan speed later in the roast is okay in some ways too - because the beans are less dense and moves better with a weaker fan.
Presets for i-Roast #2:
Preset #1: total roast time 10 :00 min: 450 degrees for 10 min - This is the hotter setting - and I always stop the program early. There is a note in the I-Roast 2 manual stating that this program is designed to be used with half a batch - 70 grams. You can use a full batch, but be careful to stand by to hit cool.
Preset #2: total roast time : 11:30 min Stage 1: 455F for 6:00min; Stage 2: 400F for 4:00; Stage 3: 435F for 1:30
Sample Roast Curves for Specific Coffees:
Here's the roast curve that I use for almost all samples to get a City or City plus roast (which is considered a cupping roast I know and is probably lighter than most folks like):
Total roast time: 9:30 min
- Stage 1: 350 F for 2:00 min
- Stage 2: 400 F for 3:00 min
- Stage 3: 460 F for 4:30 min
Island Coffees: Coffees from Jamaica, Hawaii, and to a lesser degree Puerto Rico, have a lower bean density because these island coffees do not have the altitudes of such origins as Kenya. They benefit from a lower initial temperature during the warmup time. Here is the program I am currently using for a City roast:
- Stage 1: 350 degrees f for 3 min. ( = 310 f onboard thermometer reading)
- Stage 2: 400 degrees f for 3 min. ( = 360 f onboard thermometer reading)
- Stage 3: 450 degrees f for 3 min. ( = 375-390 f onboard thermometer reading) (It might be wise to make the last stage 3-4 minutes, then simply stop the roast manually when you reach the "degree of roast" you like - this is always the best method to target an exact degree of roast.)
Brazil Coffees for Espresso: Like the Island coffees, Brazils come from lower elevations. They benefit from a slower warmup and a longer overall roast. For Northern Italian Espresso I like this program, and you can use it for other light espresso roasts too:
- Stage 1: 350 degrees f for 3 min. ( = 310 f onboard thermometer reading)
- Stage 2: 460 degrees f for 3 min. ( = 370 f onboard thermometer reading)
- Stage 3: 470 degrees f for 4 min. ( = 390 f onboard thermometer reading)
Some additional thoughts:
A basic profile I am using is my lower-heat warmup profile. It benefits all coffees, and only causes problems with really dense seeds that need a higher initial temperature. Basically it is
- 340 for 2 minutes --this will give you a high speed air pattern to aid in really even initial heat distribution
- 390 or 400 for 3 minutes -- this raises the temperature right to the verge of first crack
- 450 for 4 to 6 minutes -- with most coffees, 4 minutes will give you a City Roast, 5 a Full City, and 6 gets you to the door of 2nd crack.
I think the best way to use the curves in the i-Roast is to regulate initial heat distribution. Air roasters, even the professional Sivetz air roasters, have never allowed a slower warm-up "ramp" and this is where you can cup quality by letting the coffee accept and distribute heat according to its physical limits, not forcing the heat on too quickly. Once heat is distributed from the core to the exterior of the bean evenly, then a higher roast temperature that allows the coffee to pass through the cracks can be applied. If this temperature is not too excessive, the cracks will happen in a slow and controlled way, with a clearly delineated pause between 1st crack and 2nd crack.
At first I thought I would be using the stages of the i-Roast program to regulate the finish of the roast, but realized through trial and error (and cupping) that this doesn't make sense. The fantastic thing about programming a temperature over a period of time is to get the batch on the right "track" for the final finish roast temperature. As I said, no air roaster has offered this before, and despite the fact that the buttons and programming technique on the i-Roast is ...well ... lame, and despite the fact that the temperature you program is not the temperature you read on the onboard thermometer, the i-Roast is still a "next step" in air roasting because of this feature.
One last thought ... don't get hung up on overall roast times. 8 minutes, 11 minutes, 14 minutes ... it DOES NOT matter! Roast times are only relative to the method of transferring heat to the coffee. Air roasts are not supposed to be as long as drum roasts because they have the ability to transfer heat rapidly in a high velocity air stream. A drum has to conduct and convect heat to coffee much slower to avoid scorching. With the i-Roast, let the coffee be your guide in programming curves. Watch what the coffee is doing, and adjust your curves to what you observe. If you blast it with hot air, and 1st and second crack blur together. make adjustments. If you stall it, and the coffee just sits there, not developing but being exposed to heat, then you are baking it ... make a change. But a particular roast time is not a goal, and a 10 minute roast in one machine has not relevance to a 10 minute roast in another machine, not in terms of degree of roast, quality of roast, or cup quality. I hope this helps a bit... Tom
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