HomeRoast Digest


Topic: I think I hit the sweet spot! (3 msgs / 98 lines)
1) From: Scot Murphy
Just got done roasting, and I decided to do things a little different  
this time. You may recall that I use a SC/TO, and that I have a  
digital thermometer which probe sits between the beans and the TO.  
That means I am not measuring the ambient temp of the beans but the  
air, which I take into account. Now, usually, most of my roasts I'll  
let climb to 400 before I hold for a minute, sometimes holding for a  
minute at 350. I just do this by turning the switch on and off. I log  
the temperature rise in 5-degree increments, adding the beans at 250  
(after which the temp dips to around 200), and after some recovery,  
the temps usually rise at about 4 to 6 seconds (roughly) per 5  
degrees. Sometimes a little more, and that rate slows as the  
temperature passes 400, usually. I used to get to around 400 in 4  
minutes, but changed that in order to try to avoid the baker's- 
chocolate-powder smell of my ground coffee.
On thing I had noticed in my roasts of the Dulce and the India  
Matadakad was that the cracks were quiet and sparse. The beans were  
cracking, all right, the seam splitting with cracks at the ends, but  
I wasn't getting anywhere near the dramatic cracks I used to with my  
old Poppery. Most of my roasts are like that, and I understand that a  
slower roast means a more protracted crack, but all my roasts seemed  
quieter and slower than they should have been.
So today I tried the very, very last (sniff!) of my Brazil Fazenda  
Ipanema Dulce, but did this: I let the temp climb up to 350 and  
decided to hold it for two minutes. After that I let it climb to 400,  
then held it for 2 minutes again. When I did this, I got a slightly  
earlier 1st crack in terms of temperature (around 430, rather than  
450), but surprisingly, the crack was much louder--and more rapid! I  
got a fairly continuous 1st, which I hadn't been for that bean. The  
crack also seemed to last longer, about two minutes longer than  
usual, so I thought, I must be on to something. So I tried my India 
(na) Matadakad and did the same thing: 2 minute hold at 350, 2 minute  
hold at 400. Not only did I get a similar response in the crack--a  
little earlier, louder, and more protracted--but at about 9 minutes,  
I got the most *wonderful* smell.
That's why I wonder if I hit the sweet spot! This aroma came from my  
SC/TO that, for about half a minute (during 1st), that seemed simply  
perfect: perfectly sweet, perfectly nutty, perfectly toasty,  
perfectly coffee-like. And now I have to wait a couple of days to try  
it--maybe four days for that perfect rest period. I want to try it  
NOW!!! I'll content myself, in the meantime, with an adult beverage  
or two. :)
Dang, this is why I love home roasting!!
Scot "beer's no substitute" Murphy

2) From: Greg C. Rose
Scot,
I use a SC/TO as well, and I've noticed that the cracks are usually quite
subdued too.  I also found that my TO isn't hot enough to roast the beans
up to 2nd crack well.  (I had the heating unit of the SC disconnected.) 
So now I've rewired the SC and have its heating unit on a toggle switch. 
This way I give the roast an additional boost when I feel its lagging.  I
find that the cracks are more pronounced now because of the faster heating
time.  I believe that the cracks were soft before as a result of most of
the water escaping before the bean temperature reached 1st crack.  
Congrats on finding the sweet spot.  The real test comes now to see if it
is repeatable with a different bean.
Greg
Firin' up the SC/TO right after work

3) From: Peter Zulkowski
Hi Greg,
You may need to adjust the thermostat in your TO, or better yet connect 
it to a toggle switch also.
The element on mine is now controlled with a standard wall switch (house 
kind) that I mounted in a electrical box.
Actually, I used heavier gage wire to the element and put an electrical 
plug on the end of it. This plugs into the box and is controlled by the 
switch.
This set up lends itself easily to control with a PID also.
Best,
Happily camping, here in Gloucester, MA.
Greg C. Rose wrote:
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