I have gone from an air popper to a Huky 500. Lots of learning to do!

Solid drum, dimmer switch on fan, IR burner.

1. What is Bean Temp and what is Environment Temp?
- My understanding is that BT cannot be accurately measured (how could you measure the inside of each bean?!), and ET is the drum temperature?

2. What is the probe measuring and what is the gauge on the Huky measuring?
- I have a TMD-56, so I'll be running Artisan. I would think that the gauge on the Huky is measuring the drum (ET?). So I won't be able to graph that information in Artisan?

3. Charge temps, sample roasting, etc.?
- What is a good temp to charge at? I know this depends on every individual coffee origin and elevation, but I cannot find a list of suggestions. Is there a resource out there that covers this?

- Will keeping the damper closed help reach that charge temp quicker?

- Opening the damper should allow me to elongate specific points in the roast where I want to emphasize that point's characteristics, correct? (BTW, where is the air intake located? Bottom? Would placing a fan near this help to elongate those even more?)

- How should I control the fan during roasting and cooling?


I understand that this is a lot to go over, but I have spent quite a few days on this, and haven't really been able to put together anything real discernible.

Thank you!

Welcome, David! Nice job on the move from popper to Huky!

Let's start with the terminology. For basic logging of roasts we generally look at BT (Bean Temp) and ET (Environmental Temp).
Other metric that some use are: MET (Maximum Environmental Temp-generally based on the temp of the surface of the drum to gauge conductive heating), exhaust temp (mostly for air roasters) and ambient temp (as outside air is utilized for airflow through the roaster and can impact how much burner needs to be applied to overcome cooler external temperatures.

While you are correct in the fact that it would be extremely difficult to get the internal temperature of the bean, BT is as good of an approximation as we can get. It is based on the combination of external bean temperature and the air that is in close proximity to these beans.
ET is just what it means, the general temperature of the air inside the roasting chamber.

The analog gauge is placed to measure ET (in celsius) and the thermocouple located under the trier is for BT.

For general charge temps, I keep them in the 350F range. If the drying phase is taking too long, or I feel I have to add too much burner to keep the roast progressing: it might be a good indicator to use a higher charge temp (or fewer beans!)

Regarding the damper. I find it just about useless. Since you stated that you have a dimmer for the fan: double-useless. Airflow is a point to which will take much experimentation. Best would be to run the roaster empty with at a set burner level until the internal temp stabilizes (approx. 10-15min.) Then watch the effect varying levels of fan effect the temps. Watch the burners too. Sometimes an increase in fan speed feeds more air to the propane/butane mix.

Buy a large amount of cheaper beans of the same variety so it will be easier to see the differences changes in your profiles make.

Most of all: have fun. It is just coffee, after all!

Thanks, Bryan! Just ran the first batch, and boy did it burn...

First of all, my Amprobe is way off, I think. When I was using the popper, one of the probes ended up burning somehow, despite being a K-Type. I think this messed up the thermometer as well. See the attached image for why I think that...

I really couldn't keep up with how fast the roast was going, because it wasn't making much sense. Also, I feel a bit overwhelmed. Should I control the heat at the blue valve or the black one? (On the IR burner.)

I attempted to follow Kfir's suggestions here, but it just went way too fast... I never wanted to hit 1C. Rather, I would have liked to have dropped around 410°F (210°C). But with the Amprobe going bonkers, and not knowing how the ET related to the BT, I wasn't sure what to do, especially trying to juggle two different heat controllers.

OK, well something is certainly amiss. Not sure what it might be though.

Let's look at it logically. First crack normally occurs in the vacinity of 400f. So we'll add the offset of +140F to every guidepost.

Charge temp now becomes 440F. Your Turn around point (where the freshly charged beans stop decreasing the BT and begin to climb-generally somewhere in the 180-230F range) is now 320F.

First crack happens at (adjusted BT of) 400F @ ~6min. VERY FAST.
Second crack happens at (adjustedBT of) 440F @ ~9min again, VERY FAST.
Drop temp would be around 460F: darksville. Not surprized you used the term "burn".


By my logic, the temps are off by about 140F. The average Rate of Rise from the Turn around Point (TP) to End of Roast (EoR) is around 20/min, which is quite common and a rather good ramp.

I'm not familliar with the IR burner or it's available power levels, but with my open-flame burner, I rarely have to go above 50% of it's available range.

Can I ask if you have the chance to test your probe in either some ice water or boiling water to see if it is reading properly? Is there potentialy some manner of conversion or offset that is being processed by the Amprobe?

It's a learning curve, for sure. Keep at it and take good notes. It's only a failure IF you don't learn from it...


Cheers!

Bryan

Good luck with the Huky, there's a lot to keep up with for sure. It might be worth a try to hand chart some roasts with heat, air, time, temps. Yes the damper does work just like all the other commercial roasters out there. The problem with it is 1. Too small 2. No visible settings. I've only done several roasts on the Huky but did run some air flow tests; and you can run up to drying with it closed (fan on). Then slightly cracked to just before 1C; adjust as necessary after that.

Both heat controls work, the stove have three settings with the added needle valve for fine tuning. It would be simpler to run on high and use the needle valve/pressure gauge. My gauge was marked with a sharpie by the previous owner; good idea.

My opinion is the Huky IS the ultimate gas hobby roaster; totally manual with all the control points the big boys have; at a much lower price point.

Also, please provide some data point for us so that we don't have to make assumptions.

How many grams did you charge?
What burner and/or fan adjustments were made during the roast?

Thank you.

I definitely plan on keeping notes once I am able to keep track of where I am in the roast more accurately. Much different than an air popper!

I'll be roasting on weekends on a Diedrich IR-3, so this is a great little sample roaster, and I can't wait to get a hang of both of them.

The Amprobe is probably the most difficult thing to deal with. Even when I had it going before, it was hard to use and sometimes it would get stuck in REC mode without my knowledge of how to get out of it. Testing the Amprobe with our Bonavita kettle right now. The kettle just clicked off and the Amprobe reads 210°FK (what the heck is FK?).

With the Huky, I think I realized what the issue was... I was using the blue-handled valve on the IR burner to adjust the flame. Umm... that adjusts fuel pressure. Haha! So, with some advice via email from someone who owns a Huky, I will be keeping the fuel pressure around 2 kPa (not sure what that means haha, but WAY lower than it was before).

edit: This roast shown above was 150g
Fan adjustments made were based on Kfir's suggestions of 6-7 seconds every minute. Personally, I don't know if that would work that well.

The needle valve (blue) knob on the Huky, is what I use to adjust the flame on my 800n and assume that is why Mr. Li installed it on his IR stove. My 800n gas gauge maxes out at 3kpa whereas the Huky goes to 7.5kpa. The stove knob appears to have only three settings; low, medium and high. Probably a good idea to operate the stove without the roaster on top to get a feel for controlling to heat. I am curious why Mr. Li installed a 7.5kpa gauge on the stove; that's a lot of gas for a small roaster.

The gauge goes that high, though the actual kPa is actually 5.25.

The last two roasts were much better! Weight retention at 83% and 81.8%, respectively. 83% was a washed Ethiopia Lomi Tasha, while the 81.8% was a honey-process El Sal. I have three small samples from an importer, so I don't want to burn through just one while I get used to this setup. I think I'm getting there.

Ethiopian ended at 24 minutes, while the El Sal ended at 14. While the Ethiopian was a lighter roast, it ended up baking in the drying phase. For the Ethiopian, I followed Kuanho's instructions on roasting (emailed him), and his suggestion for keeping the fan off and valve closed during the drying phase (up to 160°C) turned out to bake the coffee. With the El Sal, I had the valve open and fan on. Next time around, I will probably decrease the drying phase even more by increasing the heat delivery.

Hi David.

First of all I think that your Amprobe thermocouple settings are wrong, it's probably not set to read K-type.
Chris had a similar problem, its worth to check your meter:

HUKY 500 final specs and some Q's about dataloggers

Regarding the roast, if it's too fast just use less heat.
for a 150g batch try a 40-50% less heat and aim for a 4 min drying and 8-9 min FC.
You can experiment with a longer stretch after FC if you prefer more body, caramels and less acidity.

The roaster sweet spot is ~350g but it can do a great 150g or even 500g if you know how to control it and plan ahead.

Airflow can help you achieve a faster roast profile but to my opinion too much is not good, my previous recommendation works well for a relatively slow profile for espresso.
I recommend that you experiment a lot and see what works for you.

I can tell you that even after almost 2.5 years with my Huky I am still doing experiments and learning, you can do almost any roast profile imaginable if you know the roaster well enough.

Enjoy the journey...

Kfir.