Hello everyone,

I am relatively new to using a drum roaster, and I'm curious what your philosophies are on how to maximize maillard/yellow without baking or stalling the coffee.

The coffee I'm roasting now is a Rwanda Miko Remera #58 from Nordic Approach, which is a quite dense washed Bourbon that has characteristics between Kenya and Ethiopian washed coffees.

My first Roast was a medium charge with heat added gently at the turn. The yellow started a bit late and I had to rush through the Maillard to ensure that my roast doesn't go for too long. Heat was increased slightly at 7 minutes until I heard a rolling FC around 8:20. Then I dialed it back down a bit to allow a slow down during FC. This was a 700g batch on a Buckeye 2kg roaster. Drum speed at 5, fan speed at 5/10 until 7:30, at which point I raised to 7/10. FC ended about 15 secs before I dropped.

This coffee cupped 24 hours after roasting had a sharp citric acidity & sugarcane sweetness up front with a rather hollow middle but a long, syrupy finish that was wonderful albeit a little smoky (not roasty!) from being so fresh. I'm wondering if this coffee will open up quite a bit in 2-3 days to release more aromatics and balance out in acidity/sweetness due to a more efficient extraction.



***The Omron probe reads are lot of the faceplate and environment temperature, which results in the readings looking weird. For all intents and purposes, the absolute temp reading is a relative indicator of the profile and not an exact temp measurement of the beans. The wonkiness in the RoR curve comes from the times when I opened the trier to check the bean color.

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For the next batch, I am thinking of adding more heat at the turn with 6/10 airflow to get through dry a bit faster. At 3 minutes, I will slowly lower the heat so that it will maintain a slower, yet steady momentum to drag out yellow while still hitting FC quite hard. I am aiming for 8-8:30 FC and 18-22% DTR. I want to keep this coffee very light in order to highlight its rosehip florals and sugarcane sweetness. I'd simply prefer a bit more pronounced sweetness & body and a little less citric/acetic acidity to bring out a better balance. I would use this in filter preparations & aeropress, and possibly a lower pressure (7-8 bar), longer espresso shot (~40 sec).

Any advice would be greatly appreciated!

Cheers,
-David

Sugars are converted to acetic acid after about 200C and then break down at darker roasts. Decreasing acid and keeping the roast light can be achieved by stretching FC duration (e.g. to 3 or so minutes) and decreasing temp rise past FC. I assume rushing to keep roast duration shorter would contribute to this. Why did you need to keep roast duration shorter?

Sounds like you are on the right track. To draw out maillard flavors and get a light but developed finish, charge hotter and add more energy during drying to establish more initial momentum, than feather down the gas progressively during the maillard phase to lengthen it and enter the development phase more gently (but with enough momentum to avoid a stall). I like to bump up the air a bit at the start of the maillard phase as well.

Let us know how it goes!

All interesting info. I am learning a new roaster and finding the answers right on target with what I am finding.

Going from a Quest to a gas roaster is a big leap in learning but things are more controllable now. I can slow down the roast much more easily with gas and air flow.

I have had much success with charging at lower temp, having my TP in the 70C range. (Adjust to taste... ) Around TP I hit the burner quite hard. This approach builds up a good momentum in the drying phase and makes it easy to adjust the following stages. (My RoR during the drying phase hits around 18-20C/min and I try to have my RoR at around 14 at TP, aiming for 8-10 when going into 1C.) The drying phase really does nothing when it comes to taste, but it's the place where you build up and prepare for Maillard (which builds up for development...).
As you are roasting a high quality coffee (I know Nordic Approach coffees quite well...), it should react quite nice to this approach.

Thank you all for your insightful replies!

From my most recent roasts, I am understanding that much of the roast's profiling is initially setup by the charge temp & how much heat I apply at the turning point. A successful dry sets up slow but steady yellow into a powerful, fully developing FC. These are absolutely key elements for maximizing coffee flavor, much more so than looking simply at DTR.

In other words, I previously thought that most of the coffee's development happened post FC, but actually there's more to it than that. post FC is merely a finalizing of what's happened in the previous processes of the roast.

Well said.
This is why the terms "drying" "yellowing" "maillard" "development" phase are misleading. these things all happen throughout the whole roast.
Yes certain things happen above and below certain temperatures, but these phases are probably not the best way to split up a roast plan.
Phases, ROR, DTR, ect. are all tools to help execute a successful roast. But none of them solely guarantee a successful roast.

I would note that heat shouldn't all ways be added at the turn. It could be before or after, depending on the coffee/equipment.

treq10 wrote: From my most recent roasts, I am understanding that much of the roast's profiling is initially setup by the charge temp & how much heat I apply at the turning point. A successful dry sets up slow but steady yellow into a powerful, fully developing FC. These are absolutely key elements for maximizing coffee flavor, much more so than looking simply at DTR.

In other words, I previously thought that most of the coffee's development happened post FC, but actually there's more to it than that. post FC is merely a finalizing of what's happened in the previous processes of the roast.