Analog Drum temperature and digital BT, first time roaster

[gintaras]

I am new to roasting, and I'm not sure what you call the drum temperature probe, DT?
I ordered my Huky with an additional digital probe, but I never specified where I would like it installed, and when I received it, it was installed above the drum, as far as I can tell, this is what is referred to as an MET probe. In hindsight, I would have had it installed to read the drum temperature instead.

My question is, because I want to get started right away, at least try roasting, should I just leave it as is? Or would it be beneficial to move the digital probe from the MET location to the drum location, basically swapping the analog and MET positions.

And I going to have enough data to go off of by just using a drum temperature (pre-drop), charge temperature, and bean temperature?

I feel like I am going to have to guess at the drum temperature once the beans are roasting, and I don't know what temperature to shoot for. 

Is the MET probe beneficial in the scenario where I don't have an accurate DT reading (due to the Celcius analog gauge)?

Sorry for all the newbie questions, but that is what I am, a complete newbie, I have never roasted coffee at all.  I have looked at the resources section here, but not really finding what I am looking for, such as what the drum temperature should be for your drop temp, and where to keep the bean temp during the roast..

I would love to sit in on a roasting session with someone if there is anyone in the Chicago area.

[jyalpert]

Hello,

At first, don't worry about the drum temperature (commonly referred to as ET, or Environment Temperature).  Just watch the Bean Temperature (BT) for now.

When planning out your roast, you want to watch a few markers:

- Charge temperature: start around 400F for a 250-300g roast on your solid drum
- Turning Point (TP): this is where the bean temperature stops falling and begins to rise.  Artisan can be set to automatically mark this for you.  Typical TP is around 1:30.  Beyond 1:45 is considered too slow.  You can adjust your TP be either charging at a higher temperature, or applying more heat at the start of the roast
- Dry end (DE): this where the beans pass about 300F and start to yellow.  Typical drying time is around 4:00.  More than 6:00 is considered very long.
- Ramp: the time between DE and First Crack start.  Typical times are 2-4 minutes or so.
- First crack start (FCs): where the beans start to pop like popcorn.  Arrives at about a BT of 390.  Most people mark the start of FC when the popping starts to pick up (there are always a few outliers that pop early) - say, when you hear 2-3 pops in as many seconds.
- First Crack end (FCe): when the popping subsides.  Typical total lengths for FC (FCe-FCs) are 1:30-2:00 or so.
- Drop: this is the temperature at which the beans are dumped from the drum into the cooling tray.  Any time after FCe is OK.

You can also roast up to second crack, but I never do.

Now, what you'll want to do is, after you charge the beans into the drum, keep some heat on (say 2.0 kPa), little or no fan, and let them reach TP.  From there, you will control the roast by watching your BT rate of rise (RoR).  Artisan will indicate this for you on the screen.  A RoR of about 25 degrees/minute will get you to DE in a reasonable amount of time, typically.  After DE, you'll want to keep your RoR fairly steady or slightly decreased, maybe say to 20-25 degrees/minute or so.  This will take you to FCs.  As you approach FCs, you'll want to lower the power to almost nothing.  The beans release their own heat during FC, and if you are adding heat as well, FC will happen very very quickly (which is bad).  After FCe, you can leave the power pretty low and cook the beans as long as you like.  BT drop temperatures of 425 or so are typical.

Things to note: when you first turn on the fan, it draws hot air into the drum and your BT will rise.  Some of that is real and some of that is your thermocouple seeing hot air.  Don't overdo it with the fan, it's a delicate balance.  Your goal as a new roaster is to simply see what happens as the roast progresses, practice trying to get control of the roast curve, and try not to start a fire.

[gintaras]

Excellent! Thank you for that very informative reply, this is exactly what I am looking for.

[gintaras]

OK, I have a lot to learn about heat source control and fan control.
I hit the TP at exactly 1:45, and then I guess I added too much heat.
FC was at 5:02, FCe was at 6:56
Drop was at 7:59.

I dropped in at 463, I had the leads for BT and ET switched, you would think that T1, which has the big display on the Center 301, would be BT in Artisan, but it is not.

So I was watching ET, thinking that it was BT, so the temps got too high.

I feel like I am having to delicately balance between adjusting flame and fan, but maybe I am over complicating it, and perhaps I can get by with just flame control while leaving the fan at 50% after I hit DE.
I believe I hit a Full City or Dark in 8 minutes. The beans smelled almost like burned popcorn, but not quite as bad. 

I have attached my Artisan log file, but again, since BT and ET leads were switched, it might not be of any help.

[gintaras]

Did another roast this afternoon, using 250g, and I didn't ramp up the heat too fast this time, the difference is amazing!
This is my second attempt ever at roasting, I think I need a little more heat for a bigger RoR though...  input anyone?

[hankua]

Looks nice, 2min RD and midway between 1st and 2nd crack. What kind of beans did you use?

And how did it taste?

[gintaras]

I used these Ethiopian Yirgacheffe beans.
http://www.ebay.com/itm/290950804222?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Unfortunately, I am unable to get an accurate tasting, I have a cold.  But my roommate says that it has that acidy lemony zest that made me choose an EY in the first place.