Coffee roasting really is simply an art form. Nothing is more true of this than when you roast on the RK. The reason for this is that you don’t have any computer controls or any automation to roast for you. With this form of roasting, you will become a true expert of the trade very quickly as we roast entirely with sights, smells, sounds, temperatures and times. What I will document here is what works for us and what seems to work really well for most of our customers. Undoubtedly there will be someone who will say that roasting should be done this way or that and you’ll get better roasts if you do this or that.
That is simply the beauty of coffee roasting. Every coffee roasts differently, has an ideal roast temperature, and even a roast time. The quality of the coffee you choose will determine the ultimate perfection of a coffee. Conversely, you can ruin a near perfect green coffee by roasting it incorrectly.
A Colombian coffee may have an optimum roast at Full City and a particular Salvadoran coffee may not be too great at Full City, but begins to really shine at Full City +.
So if you truly wish to master the art of coffee roasting, then you really should study each individual coffee that you buy, and understand to what degree the coffee should be roasted in order to achieve maximum flavor in that given coffee. Tom Owen at Sweetmarias.com has a database of coffees and what their ideal roast should be and should serve as an excellent reference as to what you should try for on your roasts.
I, personally, have only scratched the surface in obtaining excellence in coffee roasting. And will always be learning. I once had a conversation with someone whom I consider an expert in coffee and he told me that even after 20 years, he is still learning new things about coffee every day…
I suppose I have a long way to go and a lot to learn even now.
There are many true artisans and roast masters out there that wouldn’t be happy with my position that I take when I roast. I suppose I am a bit of a practicalist and frankly have entirely more to do on a daily basis than what the average person should have. I basically run 3 businesses and have a family too. As much as I would like, I just don’t have the time in the day to be ultra-focused on the art of roasting like some folks do. I’ll just settle for happy customers, repeat orders and real good coffee.
If you have the time to become a top-notch expert on roasting, then I am truly envious of your skill and dedication and sincerely, we need people like you to teach the rest of us how to roast better and to perfect the art and tradition of excellence in coffee roasting.
Personally, however, I find that just about no matter how I roast, or for that matter, what coffee I roast, my customers are just flat out obsessed with the coffee that I give them.
I suppose that is a testament to the excellence of Ron’s drum design. It just works very well on any coffee, and roasts as well, or better, than the really expensive commercial roasters.
The reason that I tell you this, is that particularly if you are new to coffee roasting, then you simply don’t need to be afraid of roasting, or producing bad coffee. The system is very forgiving and in my opinion, you actually have to work at it to make bad coffee.
In my experience, the vast majority of Americans are simply accustomed to drinking Folgers and other low quality brands. They drink it because it is cheap. Even the national brand that you see hocking $4 cups of coffee on every street corner in every major city nationwide is peddling terrible dark sludge in a cup that supposedly is the public standard for good coffee.
Quite simply, most Americans have no concept of what fresh roasted coffee is. Even to the point of people saying “I don’t like coffee, it’s too bitter.”
People don’t know that good coffee simply isn’t bitter!
So for that reason my tips to the new roaster would be:
Don’t spend a whole lot of money on a Ultra High Quality coffee.- My experience tells me that no matter what bottom-rung moderately fresh coffee I choose to roast, my customers are falling over themselves trying to get at it. When you are starting out, your technique wont be perfected for some time, so start out with a cheap coffee, your customers will love it regardless.
Don’t obsess about perfection and micromanagement of your roasts- You will find that very small fluctuations in roast temperature and time really won’t make that much of a difference in the end result. Your customers are going to love it anyway if you follow some basic guidelines. It’s not hard to win when you average customer is used to drinking a cup of dirt each morning. 🙂
Your average customer will never be able to tell the difference between the Nutty-Chocolaty Guatemalan and your Citrusy Colombian, but they will sure know good coffee when it hits them.
When you get the general hang of it, you can start learning more and take your skills to perfection.
Coffee is ideally 10%-14% water weight. In my work in Green Coffee in Colombia, we would strive to ship coffee as high as 16% so that it would arrive at the customer at that magic 14% moisture mark.
During the roast process you can expect to lose up to 20% of the weight of the coffee due to moisture loss and burning of oils and other interior pergamino skins in the form of evaporation, smoke and chaff.
So for every pound of finished coffee that you require, add 3.2OZ or 20% extra coffee to your drum. I found that this number works well for pulling the roast at second crack. So use this following table as a rough guide. Every coffee is different so use this as only a rule of thumb. If you roast well into 2nd crack, you will lose even more weight. So, in general, the longer or darker you roast, the more and more coffee you will have to provide to complete the volume (12OZ or 16OZ) that you intend to sell.
To restate, a vienna/french roast will take more or less 1/3 more beans to make 1 pound of coffee as compared to a full city. Plus, it will cost you more gas to get you to that point. So, in order to reduce cost per pound keep your roast times shorter and less dark if you have the choice.
Finished Roast Volume
1Lb 3.2 OZ
2Lb 6.4 OZ
3Lb 9.6 OZ
4Lb 12.8 OZ
7Lb 3.2 OZ
8Lb 6.4 OZ
9Lb 9.6 OZ
While were on the subject of green loads, the 4, 6, 8 and 12 pound drums are best rated for 4, 6, 8 and 12 pounds of green coffee, not finished coffee. That said, I have, the drums have been rated with a MAX load, that you can attempt if you have extra heat. With this method you will get decent, albeit possiblyslightly uneven roasts by adding a few degrees of temperature to my standard roast profile.
***PLEASE NOTE THAT THESE SHOULD BE CONSIDERED ROUGH RULES OF THUMB, EVERY GRILL, COFFEE, AND PERSON WILL ROAST DIFFERENTLY. USE THESE NUMBERS AS A STARTING POINT AND LEARN WHAT BEST WORKS FOR YOU AND YOUR COFFEE.***