The smallest particles in coffee grind are called “fines”. First fines was said to attribute bitterness and bad flavors to the coffee. Now fines are considered important to make coffee taste great.
How can fines end up giving opposite taste impressions ?
I have long suspected it had to do with how the fines were situated in the grind: The fines can either stick to larger particles – or to other fines.
Each result in a different taste: when fines are attached to bigger particles they act as part of the large particle in the extraction and do not over-extract as when they are separate where fines only stick to other fines.
When you get advice from other roasters … and in particular if you want to repeat a roast profile from others … its important to know their taste preference.
What roast degree do they prefer ? Clairity or full bodied ? What kind of aromas ? Acidity ? Sweetness ?
We dont like the same things in coffee. But also; we dont notice the same things in the taste ! So much is going on in the taste of coffee – we notice what we focus on.
Some immediately notice bitterness. If the coffee has any bitterness they dont like it. Maybe they like a light roast with clairity and fruit/flowers aromas. And prefer no roasted or burnt flavours at all.
Others only like coffee with solid burnt flavours, but really dont pay attention to bitterness. Thats in the darker roaster end. They find the light roast thin and missing what good coffee should taste like.
This is Henrik and me (Therese). He loves very dark roasted coffee – like they do in Italy.
I find it tastes like a car workshop and awful burnt. I dont like it. But its fun to explore some times.
Normally I roast quite light (in the range of 1 minute from 1st crack start). But I am not at the lightest end of the scale. Coffee roasters like The Coffee Collective here in Denmark and Tim Wendelboe in Norway are a bit lighter than me.
Photo by Ida Kofod from Kontra Coffee.
She took out a sample each minut during a 14 minute roast – to show the color change.
George Stavrinou from the Bullet community (he is a Bullet owner in Australia) asked me; what I was trying to achieve with my roast profiles regarding to taste.
To me the most important is:
1) Balanced taste and avoiding bad taste (bitterness, cardbord, burns and so on)
2) Get big aroma. In light roast I get a certain kind of grand aroma, that I can’t associate with a specific food/flower/whatever. But that is high up and stays as a pleasant aftertaste in the mouth for a long time. This I dont find in darker roasts.
Here is an example of a good tasting and bad tasting coffee of the same bean. Much in the roast profile are alike, but not all the way. What causes the difference in taste ?
The bean is a high grown washed arabica from Uganda, the Mount Elgon mountain or the border to Kenya.
The good tasting, 400 grams, by Therese
Taste: no burn flavour, no bitternes, nice round, full body and big nice aroma
I roasted it again 9 days later. First the the curves were very close. But after 5,5 minutes the ROR levels differed. Here both curves:
The higher ROR level here gave an earlier FC; at 7 minutes in the second roast where as the first had 8:45 min.
This coffee didn’t taste good to me. It had bitterness and burned taste. And not a big aroma.
What could be causing this difference in taste ?
The development-% was around 24% for both (the time after FC related to total roast time). And weightloss was about the same: 14,3 and 14,5%
Development time (DT) was 2:44 minutes for the good one. The bad with more burned taste you would expect to be roasted longer, but no, its roasted a bit shorter: the DT was only 2:19 minutes.
3 possible explanations for the burnt taste
A higher temperature rise in the bad one: 12°Celcius (and BT ended on 181°C) … where as the good one only rose 6-8°C (to end-BT at 175°C).
When entering First Crack the bad one had a ROR around 10°C pr min. Whereas the good one was around 5. The general recommandation is to be at the 5°C level and not as high as 10°C when entering FC and for the rest of the roast.
The amrican roaster Rob Hoos talks about the importance of the middle phase: from yellow point to FC start (see his book “Modulating the flavor profile of coffee“). He calls it the Maillard phase. In these two roasts the drying phase up untill yellow point are not that far apart: 4:00 and 3:45. But the lenght of this middle phase is 3 minutes for the bad one, and 5 minutes for the good one.
Martin Kjeldsen roast of the same bean
Martin Kjeldsen lives in different part of Denmark, but we got the same bean – and the same roaster, the Bullet. The bean is from Uganda from Mount Elgon (on the border to Kenya).
Martin have also roasted the bean several times. This is his best tasting batch:
500 grams, preheat 185°C
Martins bacth was roasted 2 minutes from FC start to end-BT at 192°C. Min good one was roasted 2:45 min and to BT 175°C. But our bean probes do not measure alike. Notice the difference in FC starts. Martin at 182°C. Mine at 167°C and 169°C.