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01/12/2021 6:15 PM
@Nomad As a general rule Roasting should not exceed 20 min to second crack You are describing is baking

12/31/2020 2:39 PM
I trying another 2 cups at 200 for 45 min

12/31/2020 2:38 PM
I have a questions.. im trying to experiment with riasting.. i roasted 3 cup of nicaraguan at 200 degrees for 1 hr and 30 min.. is that to long?

12/17/2020 11:16 AM
Snow again in NC.

12/13/2020 3:51 PM
I didn't realize snow was forecasted for this neck of the woods

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Coffee and Math
Hi All,

This is my first post. I'm joining as an avid roaster these days because I derived a very simple equation that helps me choose how long to roast my beans for. I'm a newbie, so I'm still roasting on the 1970's Harvest Gold Popaire 2 side air popper from my youth. It's a low 1050 watt machine that is very sensitive to ambient air temperature changes outside. So, my roast times can very from 9-16 minutes which makes it particularly challenging to nail a medium espresso roast.

I was about to get a drum roaster, but in my hesitation I decided to take the data and see if I could come up with an equation that would incorporate outside air temperature and humidity. After that I added bean mass and wattage, and then tested on my neighbors roaster, which was 1200 watts for comparison. With a slight modification to my equation I had two identical roast from two different machines, but my 1050 watter took 3 minutes longer.

The other issue I have with my roaster is that I can only roast a couple times a day, and small batches at that. After the machine heats up, the following roasts go too quickly and I get off flavors. So, I got into the habit of roasting every morning when I woke up until I had lots of beans built up. I pulled my equation into a web page using java script so I can type in air temperature and then calculate the roast time on my phone, and then start the timer and walk away. I don't have to listen for cracks or anything. It just works.

The reason I joined the forum is that I'm tickled with the results. I'd like to see if anyone else can benefit from the web page I put together, or the equation. So, I built two web pages. The first one I'll share has you input your roast information to determine your RoastMark, which is a number that determines how light or dark your roast is. Once you have that value you can use the other web page to determine your roast time for the day. And after that you can adjust things just be increasing or decreasing the RoastMark value.

Here are the two sites.

The font is really big so i can use it on my iphone. I have spent little time on the interface, so I just works and is really really basic. If anyone is interested I can share the equation and describe it in detail. Enjoy!

Edit - Made links clickable
Edited by Koffee Kosmo on 06/05/2013 5:58 PM
Nice work, and a novel approach.
1 pound electric sample roaster, 3 pound direct-flame roaster, both handmade; modified Mazzer Mini grinder, LaSpaziale Vivaldi II automatic espresso machine. When the electricity goes out I make vacpot coffee from beans ground on my Zassenhaus hand grinder, and heat the water with a teakettle on the gas range.
RoastMark Setting:

I was away for several months when this was posted, and have just now discovered the thread. Have any HRO members experimented with the novel RoastMark Setting concept?
Ciel... seeking Heaven in my cup with ................................................................................................................. EXPOBAR Brewtus II - MAZZER Mini E - MAHLK�NIG Vario - GeneCafe - RAF-1 Extreme (Modified B-2 HOTTOP) - BellaTaiwan XJ-101
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