Hottop Manual Roast Controls (for Digital Model)

[yoma]

Re: Hottop Manual Roast Controls (for Digital Mode

Hey JavaB

I have added couple of TCs into the bean mass and agree its a very worthwhile investment.

I may one day boost the power - it may depend on the what element I need / can find.   In my experience it would make that crucial difference to get through 250+g size batches (dont want to push it too far and get a meltdown.

Greg, I will post the circuit details and anything else I can do to assist - just need to find my original notes.

[JavaB]

Re: Hottop Manual Roast Controls (for Digital Mode

Progress report....

Well prior to fitting the PID control I thought I would try manual control to see what was possible....

Using a triac control (the same could be done with Yomas circuit) I controlled the heater between off and 100% power - this was done since I will be using a SSR to connect directly to the element and not via the main board when I fit the PID.

I used the CS roast monitor - which is excellent as it give a rate of change of temperature display - and a thermocouple in the bean mass to detect the temperature.....

The HT controlled the fan as per usual and beans were loaded on the beep - also as per usual.

The heaters were on 100% until FC - which with 250g of beans arrived at 11 minutes 40 seconds..... The heater was then switched off for a minute until the rate of change dropped to about +2 degrees per minute and then the heaters returned to about 50-60% to maintain about +2 deg per minute..... with a slightly higher value towards the end. SC started at 15min 50 seconds and the beans were dumped... They are of very uniform colour..... but the proof will be in the cup.

The time between FC and SC could easily be made longer if desired. The cracks were louder than with the normal roast and FC really got rolling within 30 seconds from the first crack..... there was also a good gap between the end of FC and the first cracks of second....

So far very pleased. The HT has plenty of heater power but in normal mode this is only used at about 60% from the time the beans are loaded until they are dumped..... using the full power of the heater allows the roast time to FC to be reduced to about 3/5 ths of the normal time.... and with some form of heater control the time between FC and SC can be made MUCH longer.

[yoma]

Re: Hottop Manual Roast Controls (for Digital Mode

Hi JavaB,

Curious to know how your tasting went.
Also, do you plan to try any further manual roasts?
If so, you may like to consider the following diffs.
- Drop in the beans 2mins after the beeps...
   Hottop temp approx. 137C, TC temp approx, 230C
- Use around 220 to 225g green.
This gets to FC in approx. 10min.
Eject approx. 3 to 4min. later.
Ive found getting to FC sooner, allows more time to SC, to develop the flavour without cooking off the oils.

Regards,
yoma.

[JavaB]

Re: Hottop Manual Roast Controls (for Digital Mode

yoma,

That roast was using Malibar which requires at least 7 days resting so Ill be tasting it soon. The inspiration for this was that Malibar needs a lengthy FC to SC gap for best flavour (based on Corretto experience) and a standard HT just wont do that.......

Yes, Ill be doing more manual roasts. Greg Pullman and I will be exchanging more HT and Gene roasts to see how the results compare. Ill give your suggestion a try - but not with the Malibar as it also benefits from a slow ramp to FC..... however I have many other SO where your method would give better results.....

The HT appears to be a very flexible roaster.... but not as it comes "out of the box"

[A_M]

Re: Hottop Manual Roast Controls (for Digital Model)

BIG Heads up for Yoma [smiley=tekst-toppie.gif]


1: After much mucking about and lost transport... Finally got it home.

2: Studied teh cct and was able to piece back together the bread board which had taken the odd tango step or two during its travels...

3: Have a thermistor that might just replace teh standard HT one (same temp response profile) but can sit into teh bean mass. Existing one in the lid was Open cct.

4: Re set teh unit to standard and tested... Alll OK

5: Stripped all removable bits for soaking and cleaning.

Special insulation for between the walls in progress.

Box with Vero Board x 2 (Fan and Heater) with master slide switch to enable external or standard HT controls on teh drawing board.

[emckissock]

Re: Hottop Manual Roast Controls (for Digital Model)

1: After much mucking about and lost transport...  Finally got it home.

2: Studied the cct and was able to piece back together the bread board which had taken the odd tango step or two during its travels...

Glad you got it, I was about to ask how things were going.

the circuit board stuff ups were probably my doing, only had a brief glance at it before shoving components back in place and I suspect most fell out when I braked suddenly and it took a dive off the back seat. Sorry about that.

Special insulation for between the walls in progress.

What are you using for insulation? Sounds like a good idea.

[A_M]

Re: Hottop Manual Roast Controls (for Digital Model)

ALL is good.

Helps to look and understand what is going on rather than just accepting things...

Fire blanket from Bunnings is a good start... Just need to think about what air flow and where is best placed.

L/H side to insulate and reduce losses from teh elements is the first step...

Keep going with yours and many thanks to Yoma once again...

[emckissock]

Re: Hottop Manual Roast Controls (for Digital Model)

ALL is good.

Helps to look and understand what is going on rather than just accepting things...

Yeah, with a bit more time Id have done that, but wanted to get it to you quickly, had anyone known what was about to hit QLD, things would have been very different...

Fire blanket from Bunnings is a good start...  Just need to think about what air flow and where is best placed.

L/H side to insulate and reduce losses from teh elements is the first step...

Keep going with yours and many thanks to Yoma  once again...

Maybe not from bunnings, but great thought should fit nicely.

And once again, huge thanks to yoma. It will be sooooo much fun learning how to tweak this so I can manually roast to the profile I want.

[emckissock]

Re: Hottop Manual Roast Controls (for Digital Model)

Very brief update. My hottop has an interim manual heat control and fan still under hottop control.
16 min roast is now easy (could go faster). One side insulated with a silicone pot holder as I didnt want to block air vents on other side.

Next stage will be to try an arduino microcontroller and add multi thermocouples.
I will shortly be buying a TC4 shield for the interface to thermocouples.
If any other snobs are interested in playing with arduino/catuai/bourbon etc, or are already doing so and want to share experience, parts etc. Let me know. Doesnt need to be on a hottop, could be popper, behmor, coretto, I-coffee, TO,...