Please see linked post if you want to know what I am talking about.
This ended up being a much more complicated blog post so I have split this up into two parts. I hope you enjoy.
I am going to discuss my approach to roasting coffee. This is what I’d call my “default” roast. But to set the stage, let’s take a step back in my life to talk about the best roasting course that I’ve attended.
I am talking about the Karl Staub course that he gives, if you don’t know who he is, you should look him up, he is the inventor of the Agtron after all.
First some science: Within his course he talks about developing complex carbohydrate chains, in particular he focused on Polysaccharides. It seems that early on in the roast is where Polysaccharides are broken down to Monosaccharides and it is these that we want to make sure we have a foundation of.
Why? Because this is the foundation of sweetness in coffee. (That’s why I remember this so many years later.)
Monosaccharides, in this case are helping us build a foundation of fructose sweetness. From experience this is done from the moment we see the chlorophyll start to break down or disappear from the bean. It is at this point that you want to slow your rate of temperature rise. The marker that I use 300F/ 148C at 5 mins (this is my “default” roast remember?)
If you have set up your charge temperature correctly and the amount of energy you are applying to the roast, this slow down should just happen as the beans lose moisture and become less conductive to heat (Think about grabbing a hot pan handle with a wet towel instead of a dry one. Ouch. The moisture in the towel transmits the heat straight to your hand. This same effect impacts how coffee roasts, because it starts out with more moisture and loses it as time passes.)
This is a very important moment in the roast. From 5 mins to 7.30mins in the roast you see your coffee turn yellow then orange. When you hit around 355F/ 179C caramelisation or as I like to call it cannibalization (Why? Think of eating a raw apple and its intense acidity and sweetness, now compare that to a baked apple that has gone through a caramelisation, the acidity has lessened as well as the inherent sweetness. It’s as though the heat is eating up some of the sugars and acid as it develops other flavors.)
When you hit this point moisture in the bean is starting to get forcefully driven out and a cooling of the drum can happen by expelling gasses and a change in bean mass.
It is important to race through the next stage as quick as you can because, this cannibalization of monosaccharides and fructose is rampant, think of this guy eating all the hard work you have put into the roast thus far. (insert pacman eating fructose)
Now this is where I have to pause with my explanation of my default roast. In recent times there has been a big push in roasting in a manner that actually ignores this important development of monosaccharides.
A popular profile says to charge your coffee at a temp and with enough energy that you have a high turn time and temp and for the whole roast you are actually backing off on the gas for the entire roast for the sake of this post I will call it profile “S”.
I have seen this in action and it baffled me when I watched the colors of the bean change from green, skipping the yellow colour that I was so used to seeing and heading straight to the colour orange or the cannibalization phase.
What happened out there that had people trying this style of roast? I had no idea.
Enter Ryan Wanslow, you will most likely know of him now as the East Coast La Marzocco tech guy. Or you may know him from his Ritual days in SF. I know him as the guy who came into my world for the sole purpose to challenge everything I knew about coffee, beer, wine and popular culture.
We would have so many heated discussions about roasting and coffee on a daily basis that our working relationship almost did not work. Then, one day, for whatever reason that I don’t even remember, we clicked. We ended up setting up coffee programs together that rivaled any other company out there.
With Ryan on the tools and with a passion for exploration, together we started down a path to understand what was on trend and what was trad.
We chose a particularly sweet coffee that we could do multiple roasts on if memory serves me correctly I think it was a Yirgacheffe. Ryan roasted my default roast and the more modern roast profile which you are always backing of in gas to slow the roast down.
I’ll discuss what we found in Part 2.
With cupping as our only measure, we did two types of cuppings. A traditional cupping, using the current Q Grader cupping protocols and we also did a side by side minute to minute cupping. A minute to minute cupping is taking a sample every roast minute from the tryer as the coffee develops.