2 different Kenya profiles

[chrisdodson]

So, I was minding my own business, charging 350g into my HUKY, when out of the blue, my wife calls me for the second or third time in a row (I've learned to not ignore those calls). As I am giving her directions for an alternate driving route, I'm doing all of my usual checks and "events" that I do just after I charge my beans. And of course, in the midst of doing two things at once, I forget to reopen my air damper. I normally close it just for the moment where the beans are sinking into the drum so that none of them get sucked into the pipe.

The result was that my RoR was not very good until the third minute when I realized why my ET readings were weird. Upon opening the damper up, the fan started doing its job, and my RoR increased (55 setting on my variac if anyone wanted to know). What was weird for me was that I hit First Crack at 375F (190.5C) as opposed to 385/395 like some other coffees I've roasted. I thought to myself, ok, I guess this Kenya cracks early. What ever!

This mishap resulted in a long drying phase. When I compensated by trying to rush the rest of the roast, I didn't coast very well from First Crack to drop. You'll see on the graph that my RoR was kind of aggressive for that late in a roast.

I then roasted the second batch (same coffee, same charge weight, 350g), and roasted with my usual baseline. With my usual baseline, I ended up hitting First Crack at 385F (196.1C), which is more normal for how I've been roasting.

So I'm actually pretty excited to see the difference between the two roasts. My guess is that the first batch cracked earlier because the longer drying phase resulted in an earlier inner-bean development, thus cracking earlier(?).

Any guesses what the differences will be when I cup?

I'll post results when I cup later this evening!

[SusanJoM]

Chris, I'm really interested to know what you do before and right after charge, in other words, how do you warm up (heat and fan) , and what heat and fan settings do you use as soon as you charge.
I ask because we have the same configuration and use the same charge weight (350 gm), but I'll be doggoned if I can get the temperature to turn around before it drops to below 200.
Here is the part of the profile I'm curious about:

[chrisdodson]

Chris, I'm really interested to know what you do before and right after charge, in other words, how do you warm up (heat and fan) , and what heat and fan settings do you use as soon as you charge.
I ask because we have the same configuration and use the same charge weight (350 gm), but I'll be doggoned if I can get the temperature to turn around before it drops to below 200.
Here is the part of the profile I'm curious about:

Susan, that's quite interesting

I start everything up, and heat up using the lowest flame setting. It takes a long time, but I just like the idea of a nice, thorough, slow heat up. Sometimes I'll turn the burner a bit higher if I'm sick of waiting. Once the ET gets about 40-50 degrees above my desired charge temp, I turn the fan damper off (no air flow), and turn the flame to the absolute lowest setting before the flame cuts off. It slowly drops (maybe 2-5 degrees/minute). Once I get to charge temp., I charge, and about 30-45 seconds in, I turn my flame up to desired kpa (generally 3.25-3.75). My fan always starts around 55 on my variac.

I'm still very new to my HUKY, and roasting in general, but I'm getting clean and sweet cups of coffee.

I by no means am totally sold on the way I'm going about things, though.

Are you hoping to get your turn around point a little bit higher?

[SusanJoM]

Well, yes and no.  I read somewhere/sometime??? that any time spent below 200 was basically "wasted", so I've been keeping an eye on that.  Mine always turns around somewhere around 190.  I still get to 300 in a perfectly reasonable time, but....it has seemed odd.

I warm up for the first 5 minutes at 1.5 kPa and then drop down to .5.  I keep the fan at about 50% the whole time.  When I charge I put the kPa up to 3.5.  I have just always wondered why my temperatures cruise so low before getting a grip and turning around...:-))))   

Well, I lied, because I looked and this roast turned at 215.  I'll be darned if I can remember what I did differently though. 
Oh yes, I do remember, this is one of the two roasts I did with the solid drum.
Looking back, all of my perforated drum roasts dip below that 200 degree mark.  I really don't know if I care;  I just wonder about it...

[SusanJoM]

This is much more what my profiles look like

[chrisdodson]

This is much more what my profiles look like

Minus a few differences, our roast curves look similar.

I'm wondering why your temperature gradient between your BT and ET is so much greater than mine. Do you use BT or ET for "drop temp"?

[SusanJoM]

The only temperature I actually look at while I'm roasting is BT.  I use all three to be sure the roaster is warmed up the way I want it to be, but once I drop the beans it's all about the BT.

[chrisdodson]

The only temperature I actually look at while I'm roasting is BT.  I use all three to be sure the roaster is warmed up the way I want it to be, but once I drop the beans it's all about the BT.

Sorry, what I meant to say was charge temp. Do you charge when your ET/BT are at a certain temp?