Earlier this year I decided I wanted to up my roast capability. I love my HotTop, but I was tired of standing over the roaster for two hours to get a couple pounds of coffee. I also had a fantasy that if I could just get a proper gas roaster so that I could REALLY control my roasts and get the ROR I wanted, everything would be all better. Well, no. At least not right away.

It's easy to assume that the big roaster in the crate with all the probes and phidget, etc. will just make it easier to roast coffee. I'm not saying it doesn't. However, I had Lord only knows how many roasts under my belt in my Hottop. Temp probe not working? No problem. I still knew exactly what was going on based on the built in temperature probe. I just kind of knew what to do. It was pretty simple and easy to not screw up (after hundreds of roasts).

Enter the Mill City 500g roaster. That darn thing was exactly what I was looking for. I liked the fact that it was set up the way I wanted out of the box, as compared to some of the other competing roasters (YMMV). Then I roasted on it. It's been written on this and other forums, but I don't think you can understand it without doing it. The difference in sensitivity is, as a famous politician would say, huge (or maybe tremendous). After you screw up a roast or two, you realize that on a hottop you lose around 200g of coffee (at least that's what I roasted). Now I'm chucking 500g. That hurts. And I'm definitely going through more coffee.

On the Hottop, I know where to put the air and the heat setting to get the roast to do what I want. Now I'm running around adjusting air and gas pressure all while telling myself not to deviate too much from my standard. Did I up the air flow too much, or turn down the heat? If I turn down the gas, how much do I turn it down to without stalling the roast? You get that with logging and experience, but when you get a new roaster, you ain't got logs and you ain't got experience on that roaster.

So the grass being greener, I saved the cash up and I bought the roaster. The roaster is awesome. My skills, however, require improvement. Now I need to go catch up on some Youtube videos from Mill City.

This is interesting; I'll look forward to hearing the responses. I just upgraded from a Hottop to a Proaster 500g. I used artisan with the hottop, and was able to achieve nice profiles. I still had issues, though, of getting a bit too much convective energy, and getting uniform roasting (without surface scorching).
My Proaster uses Cropster, and I am working to set this up. I have taken several almost blind runs (ie I don't have the cropster working yet) with the Proaster using the supplied minimal instructions and the roasting temp dislpy on the machine.
All three roasts have come out much better than I ever achieved with the Hottop. My system has a Damper, with an active fan in the cyclone. I'm getting shorter times to first crack with very uniform roasting.
I'm assuming my beginner luck may have something to do with the drum construction? Or just fewer variables to muck up?

Use the videos to come up to speed.

#4 - Airflow. Joe demonstrates the cigarette lighter to learn settings for low, medium, and high.
http://www.youtube.com/watch?v=TjVas7jbOUI

Learn your three phases of roasting: drying, caramelization, and development.
Use the relative fan speeds of low, medium, and high which correspond with them. As you become more experienced, use high setting on fan 30 seconds before first.

Use Artisan to roast. Use a band of 35-40* rate of rise for two minutes and then descend to 5-7* ROR at the end of the roast.

On the 500g roaster, I add micro amounts of BTUs, bit by bit, to build up to the energy needed to achieve that 35-40* crest ... keeping it in that band until about 3:30 min of the roast.

See our website for additional guidance on seasoning the drum, roasting 101 and roasting 102. Quick, down and dirty blogs to get you started.

I went from a GeneCafe to a Huky500 and I can certainly relate to your story. There is a lot to learn, my personal journey to acceptable coffee took a few months, as I was stubborn and wanted to drink most of the coffee I roasted.
Do use BoldJava's advice and besides that get cheap beans to learn the roaster with. Really, the more beans that you can practice with, the better. Once you've found a good pattern (i.e control pattern with Air and Gas settings) for the day, you can end the session with trying out a "good roast" with some high quality beans.
As you mention that you're using full capacity charges, do not deviate from that path, just continue with cheaper beans. It's important that you start your learning experience from that end (and not having to re-learn it once you've practiced it with small charges).

This one of those "been there, done that" going from a Behmor/Hottop to a professional level gas roaster.

One suggestion from a senior member here is to find a balance point where the gas/air setting stabilizes the BT with the drum empty. It's good practice especially for warming up the machine while doing other chores although things change when charging greens.

If you use a very low air flow convection is decreased, more airflow increases convection, over the balance point decreases convection.

Another suggestion to try is finding an airflow setting somewhere between low or medium low and only adjust the gas.

Some machines can roast with a fixed gas setting and only adjust the air.

It's just a matter of learning how the air and gas work on your particular machine, practicing separately might work or help in some situations.

I feel your pain, so I'm going to share the way I approach every unfamiliar machine.

Preheat to 375F
Gas at 75%
air at minimum

Start the roast with a full charge and measure the green/yellow time and temp, first crack time and temp, and second crack time and temp.

Take those numbers and by only adjusting gas to maintain a relatively (not perfectly) smooth declining ROR, shoot for a 5 min green/yellow transition, a 10 minute first crack, and about 2:30 seconds of development after the start of first crack covering about 20-25F. In other words, if first crack starts at 390, you'll go from 410-415 in about 2:30 (where you expect to see second crack at around 420-425).

Once you've got a handle on that, repeat the same roast only this time after green/yellow transition, increase the air to medium (Bear Borton's lighter thing or BBLT) and adjust the gas to bring your declining ROR into line with your phase targets (green/yellow, first crack, and development). Next, bump the air again about 30 seconds prior to first crack (BBLT and probably about 10F or 380-385 if first crack starts around 390-395) and again, make any adjustment to the gas that is necessary to maintain a smoothly declining ROR.

Drop the roast at the same time and temp. Then cup the results. Too acidic? Maybe go a little longer and darker. Acrid scented grounds? Maybe reduce the charge temp. (You won't get that on your roaster unless you're over 400F or you're really heavy on the burners to compensate for excessive airflow.)

I know it can be frustrating, but for most of us the path to enlightenment is drinking the mistakes. I know I'm still drinking Dave's.

FWIW and seriously: Dave is a much better roaster than I am, but I get more fan mail from young girls.

Remember it's a process, not a destination. We're all learning. Get good greens, isolate the variables and you'll eventually get the hang of it.

hankua wrote:One suggestion from a senior member here is to find a balance point where the gas/air setting stabilizes the BT with the drum empty. It's good practice especially for warming up the machine while doing other chores although things change when charging greens.

At the HUKY forum it is referred to as The Henry Chang Challenge )))

millcityroasters wrote: FWIW and seriously: Dave is a much better roaster than I am, but I get more fan mail from young girls.

Remember it's a process, not a destination. We're all learning. Get good greens, isolate the variables and you'll eventually get the hang of it.

...and don't expect to be an artisan roaster after 12 roasts.
...and put more work into cupping than studying and perfecting graphs.
...and keep learning. 10 years of roasting and 2 on a drum roaster -- I tell Steve that unless I am learning something daily about coffee, he should fire me.

If you follow Dave and Steve's recommendations, you really won't screw up any roasts. Will it take a while to be able to drive your roaster like a pro? You bet! But the coffee will be imminently drinkable, and enjoyable along the way.

If you're having trouble in the beginning, leave the fan on low, drum speed on high, and just manage the gas. And know your roaster will be a bit different than anyone else's.

I've been roasting for a few months on the 500 gm roaster, and I wouldn't give anything for the experience of learning to roast with manual data logging and only a BT probe on my HG/BM roaster...I had to learn about the process of roasting coffee in general terms. Now, I'm learning to use a new machine, but the basics are still the same.

I generally drop at about 415, shooting for 20-25% dvt time after FCs, but decided I was going to play with some blends, and so decided to roast the El Salvador (FOTR #2) a bit darker than usual to blend with some other components. I added a bit too much heat to keep the momentum through FC, and before I knew it, I had rolled right in to rolling SC! Hadn't been THERE in a long time. But wouldn't you know it, with a short roast time (drop at about 10 mins at 428F), it still has plenty of nice acidity and is better than I expected...should be perfect for my planned blends.

Don't be afraid to experiment as you learn your roaster. Want to go a bit darker? Do it fast and see how you like it. Or, lengthen your roast and drop a bit lower. Don't sweat the graphs (as Dave said) and learn to trust your taste buds.