Guji Masina Natural G1 Roast Profile Dev Log

[Lorrie]

I'm back again, this time I'm roasting an Ethiopian Guji Masina G1 Natural.

If you remember last time, I was roasting a Columbian coffee, and I said that it would make a good base layer for a blend, well this coffee is going to be the high note of the blend!

When I create coffee blends I think about the structure of it in the following way:

1. A high note

2. Mid Palate satisfaction

3. A sweet/floral/fruity undertone

The washed Columbian Catura I roasted yesterday is the no.2 in this case, and a little bit of 3.

But I also think that coffees part of a blend should make sense and should be coffees that either enhance the star of the blend and the other coffees or make up for the weaknesses.

Every coffee has both strengths and weaknesses, and by identifying those weaknesses, and accepting those flaws, I will then try and pair it with other coffees, with similar taste profiles, to help make up for its weaknesses, whilst also enhancing the similar flavors between them all.

This Ethiopian Guji Masina, is the star of the blend, it's the high note, provides more sweetness, more brightness, and gives the coffee its complexity.

Whist the Washed Columbian Caturra will serve as a base note, the foundation, add to its body, and its depth. It's sort of like in music, how there are silent notes, or sounds that aren't obvious, but they add something that makes them feel more whole, more powerful.

Anyways enough with romance.

How I approached this coffee, is that it's a high dense coffee, small beans, natural processed coffee, Heirloom (so a variety of arabica species) and at about a 12 -11% water content wise give or take in either direction. So, unlike the washed Columbian Caturra, where I roasted rather aggressively and fast, for this coffee I wanted to be more delicate and gentler with it.

I want to retain as much sweetness as possible, so a shorter Maillard phase, a longer overall time, and a 203.5c or 204c drop, and a 22.3/5% DTR

I didn't achieve exactly that this first attempt, I hit my targets exactly, but for some reason the machine stopped the roast early, I think it's because it hit its recommended temp or maybe its because the RoR went to low, anyways I just increased my last point temperature by like.1 or. 2, so that it doesn't hit 0c exactly, but like 0.1c

When I was designing the roast profile I applied all the techniques I learnt yesterday. Each section of the coffee roast has a custom negative boost applied, I put this at the beginning and end of the three main sections in a roast, one at the start and end of green, one at the beginning and end of yellow to brown, and then one at the start of FC to end of roast.

For the first attempt I just set values across all zones to -1 as a starting point.

the preheat temp was also just a temp recommended by the software, the fan curve was based on density and weight, and also trying to get energy into FC, whilst also achieving my desired roast color. and also, how long I wanted Maillard to last.

And as a result, I nearly perfected the profile on the 1st attempt.

below I've attached the first attempt log.

As you can see it was a really solid attempt for a first try.

and now that I know what I know, I have applied the solution in the next version of the profile.

basically, the beginning section, which zone 1, all it needs is a lower pre-heat value, which will tighten it to the profile line, and will also tighten the RoR line, and also, I applied more negative boost in that zone.

for the other zones, which are basically perfect, I just made small micro adjustments, and added like 0.4 to the negative boost, which should tighten it a little more.

as for the results of V1

like I said it basically hit all the metrics perfectly, if it roasted just a few seconds longer it would of hit my DTR target and weight loss would have been 13.2/4%.

and whilst I was a little concerned at the beginning because some coffees were developing not completely in synced, when it did get into the Maillard phase, and the browning/FC phase, the color did resync and become uniform.

And upon inspection afterwards, the color was basically 96% uniform, only 3 or four beans were defective, and it was exactly how light I wanted it to be.

I think it's just because its and heirloom coffee, and also size difference, water content difference, species difference, because its a mixture of these things, and also being natural processed coffee, it's going to be out of sync here and there in the very early stages of the roast.

But that basically summarizes this first post.

Also, a side note, I usually wait 30+ minutes between each roast, just until it gets to 30c/28c ambient temperature, and the ambient temperature when beans are added (which I do 110g batches), is usually in the 24% ambient temp range.

I of course note this down and try and keep my roasts as consistent as possible, factor wise.

So now Ill roast this second attempt, and probably it's going to be near perfect with these adjustments made, I just got to pull out on time.

Ill update when I've finished roasting and assessing the log.

[Lorrie]

Okay, well everything went perfectly this time.

22.7% DTR, 203.3c drop, and look at this log.

if we ignore the first 2 minutes, because the PID is a bit wild at the beginning almost always, from 2:00 minutes onwards its perfect.

2 attempts and I've basically got it dialed in.

Its proof that I know how to both manipulate machine, and that I've learnt.

and that I understand the coffee.

This V2 batch was even better looking too, like 98.5% if not 99% completely uniform, and no defects.

I might just call it here honestly, cause the only thing I can change to slightly improve that first 2 minutes, is by lowering pre-heat power, which I did of course.

But honestly this just as perfect as my el avion profile I did yesterday.

and yesterday it took 7 - 10 batches to dial in, but here it only took 2.

I was just learning how to work the machine, how to dial in and manipulate the settings, and now I have significantly, hugely improved, sorry if it sounds like I'm stroking my ego, but goddamn, have I locked tf in.

every metric was hit, and everything was perfect this attempt.

22.7% DTR, 99% the same light roast color, everything else hit its target times. I'm so excited to taste this coffee you don't even understand, my hands are shaking from the adrenaline (and caffeine), I live for this.

Ill update whoever may be reading this with how the coffee tastes tomorrow when I cup it.