Re: Another Caxambu Failure
Hi Paolo
I have used the HT for quite awhile and find it a fine machine.
A couple of points that might be of interest.
The HT temperature sensor is weird as it is neither measures bean mass temp or chamber temp. If you have done many roasts have a look at the rear bulkhead where the sensor is attached. You will probably see a clear discoloration mark which crosses the sensor, which to me, indicates that the sensor itself sits hakf in and half out of the bean mass which possibly gives a reading which may be meaningless.
Also the probe is directly attached to the rear bulkhead and there is a significant lag in response to actual changes in the real environmental chamber temperature as it takes time to heat that rear bulkhead. The following data is from my records. The left hand values are from a thermocouple measuring chamber temp and those on the right are what the HT shows on its screen. A large discrepancy, which indicates the heating lag of the rear bulkhead. However when you get to the 200+ they might be reasonably close.
21.6 18
22.9
24.3
26.2
28.7
30.8
33.9 21
37.1
40.1
44.1
48.1
52.6
57.1 31
61.8
66.3
70.7
75.6
80.1
84.7 47
I find I have less control of the resultant roast with starting weights greater than 250g. Sure it will handle 250-300 but I find the end result quite variable.
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Re: Another Caxambu Failure
Thanks for your feedback, Mal.
My Hottop has a preset roast profile which to date has worked beautifully for every other origin and type of bean that I have thrown its way.
The odd thing is that maybe a quarter of the roast is overdone...whilst maybe a quarter is underdone. The rest is ok. It is as if there is a mix of several types of bean in there that each brequire different roasting conditions.
The temperatures that I quoted are not actual bean temperatures but roast chamber temperatures, which serve as a reference point from one roast to the next.
I might resurrect my Coretto for these beans and give it a go....or simply use them as compost!
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Re: Another Caxambu Failure
Gday Paolo,
I have never even seen a HotTop in the flesh, let alone used one so Im unsure about how flexible they are to use with various bean types.
From your description, it sounds as though the Brazilian Caxambu beans you have are a pretty hard bean and might need a different approach to your normal roasts. Is it possible to raise the roast temperature on the HotTop another 10-15 degrees or so in an effort to soak more heat into the beans? Youll have to keep an eye on them throughout the roast though to ensure that they dont get overdone but somehow or another, you need to get more heat into them.
See how you go and report back,
Mal.
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Another Caxambu Failure
HELP!!!!
I have nearly 10kg of green Brazilian Caxambu that I just cannot roast evenly. I bought them in August 2006 and have had maybe 8-10 attempts in an Imex and a Hottop. I had resigned myself to throw them out until today....I thought that I would give it one more try. I loaded the usual 280gm and did the roast just as I always do.
Let me point out that I have roasted over 300 batches in the Imex and 140 batches now in the Hottop and these are the only beans that have turned out revolting... every time.
First crack in the Hottop is always between 191-199C...no matter what the bean..yet the Caxambu today started at 203C.
I always dump the roast with all other beans between 204 and 208C...at the point when first crack has finished and the rough sections on the flat surface of the beans have just smoothed-out. This morning the roast was timed-out at the Hottops maximum, 24:10 which equated to 209C. I let it go this long because many of the beans looked underdone. With this mornings effort there are some beans that are too dark and others are still light.
I will let the beans outgas for a few days but my instincts tell me with an uneven roast such as this, it will be another Caxambu stinker!!
What am I doing wrong?
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