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need help on using mastech ms6514
tigertictac
Hi,

I just got my new mastech ms6514 and I am using to roast on my local made homeroaster.

My roaster look like in the picture.
It is a stainless steel local made hand-rolling drum roaster, using picnic stove as a heat source.
The temperature probe i was using is type-k TC putting in the lower part of the drum.

I've got problem with my roasting profile.
Roasting temperature always get too high, in spite of using the same gas setting.

I roasted 4 batches of 200g and coffee wouldn't dry even with 200C
I marked the dry ending when the beans all turn yellow.
And the first crack arrived at around 270C.
I attached my yesterday roast profile below.

Before I got the mastech ms6514
I logged the temperature with my normal meat thermometer, writing data into google sheets,
Never had problem before, I can dry end around 180c, first crack around 200c, maxROR around 25 with the same gas setting.

Need Help!
Thanks.
tigertictac attached the following images:
img-0899resize.jpg img-0903resize.jpg 2_24.jpg 1_20.jpg

Edited by tigertictac on 03/05/2021 7:00 PM
 
renatoa
Welcome ! And nice roaster ! BBQ grill

The tip of the probe, at least 2 cm, have to be immersed in the beans mass, else little chance to measure something relevant, imo.
Dry end at 180 C is an example of suspicios reading even with the meat thermometer.

Did you tried to compare Mastech and meat thermo calibration, by measuring boiled water side by side ?
 
tigertictac

Quote

renatoa wrote:

Welcome ! And nice roaster ! BBQ grill

The tip of the probe, at least 2 cm, have to be immersed in the beans mass, else little chance to measure something relevant, imo.
Dry end at 180 C is an example of suspicios reading even with the meat thermometer.

Did you tried to compare Mastech and meat thermo calibration, by measuring boiled water side by side ?



Haven?t try that yet. I will try next time

Thanks
 
renatoa
Temperature of DryEnd is less important, you decide the moment of DE based on the senses, look/smell, more than on temperature... but the time matters.
Drying should end in the 3-6 minutes range, with a sweet spot in the 4-5 minutes.

Regarding FC, they started before your markings on graph, but probably were silent.
Look at those bumps on the graph, starting in the minute before marked FC, those moments are the real start of FC.
Again, temperature is not relevant, could be anywhere between 185 and 210, depending on probe placement.
What's more important is the moment, ideal in the window from min 8 to 10. And the evolution after FC, avoid brutal drop or increase of RoR.
 
allenb
My suggestion for anyone wanting to pick an indication method for a consistent determination of "end of drying" is when the beans go from pale green to yellow or yellow/tan. Find the temperature where this happens fairly consistently and use this temperature. As Ren stated, if this happens past 6 minutes then you are not pushing the roast along fast enough and need to apply more heat up front.

Regarding the dip just prior to audible pops of 1C, this will normally happen up to 10 to 15 seconds prior to hearing 1C. If you aren't hearing 1C then you may not have enough energy going into 1C or you may have a rare bean that just doesn't produce much cracking sound. I would make sure your rate of rise just prior to start of 1C is at least 15 degrees per minute. Also, don't base start of 1C from 1 or 2 pops which can happen early on but listen for when a few pops happen together.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
renatoa
15 degrees rate of rise allenb wrote above are very probably Fahrenheit degrees, i.e. about 8 Celsius degrees.
 
allenb

Quote

renatoa wrote:

15 degrees rate of rise allenb wrote above are very probably Fahrenheit degrees, i.e. about 8 Celsius degrees.


Yes, I was referring to 15F/m. Thanks for the clarification. I'm glad we don't have english/metric versions of time units yet.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
tigertictac
After 2 months of not having enough time to try roasting, I finally figured it out. The problem is I didn't set the correct type of the temperature probes. I have type-K probes but the device recognized it as a type-N, that's where all the error came from.

Hope this information will help anyone who didn't read the manual like me. :(

Thank everyone for helping. Looking forward in continuing my roasting journey.
 
renatoa
Tiger, tyger, burning bright... Grin
 
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