Coffee Roasting Approach

FOR SOME REASON COFFEE ROASTING IS THOUGHT OF AS A DARK ART. LET'S CHANGE THAT. 

At Fjord we roast filter coffee and espresso with a similar approach to heat transfer but there are a few things that we tweak. We'll explain this in a little more detail. 

Filter Roasts

What success looks like to us

1. We have a coffee that is clean and transparent in taste, where we can clearly define it's processing, varietal and origin.
   
   
2. Our colormeter, a Lighttells, measures consistently within the small window of allowance that we set for each coffee. For filter roasts the windows are usually +/- 1 and between 105 and 115. 
   
   
3. Coffees have a decent solubility. This means that when we do quality control cupping sessions these roasts have a TDS between 1.2 and 1.5 at the 10 minutes mark. 

How we acheive this success

• Our filter roasts are usually between 9 minutes and 11 minutes in total roasting time, and the difference here is heavily dependent on which attributes of the green coffee that we would like to highlight - for instance; a Brazil natural process would be longer because we want that buttery mouthfeel, and an Ethiopia washed Heirloom would be very short as we do not want to dull any of its liveliness. 
  
  
• We roast our coffee in a cast iron Probat coffee roaster and have variable frequency drives that allow us to control the airflow of the roaster, the drum speed of the roaster, and obviously the gas burner. We apply each coffee with both conductive heat and convective heat and depending on the density of the green coffee and the highlight we want to draw out we will change the ratio/relationship of those two types of heat application. 
  
  That last point is quite hard to understand I assume, so I'll try and explain it better. 
  
  Green coffee enters the roasting drum and with it cool air. Focusing on convection at this point does not make sense, so the first 8th (roughly) of the roast time we are just thinking about how to utilize heat transfer from conduction (a hot drum, low airflow to not let heat out, increasing bean heat as fast as possible while they are at their most moist). 
  Once the exhaust's rate of rise hits 0*C per X we know that the green has soaked up the conductive heat we have applied and that it is time to switch our attention to convection. Cue increased airflow and increased drumspeed. 
  
  
• Once filter coffee roasts hit first crack we mark that time and, depending again on the highlight, let them crack in the high airflow environment for between 45 seconds to 1:30. 
  
  
• We aim for a drop temperature between 5*C and 9*C above the crack temperature. 

 

Espresso Roasts

What success looks like to us

1. We have a coffee that is clean and transparent in taste while maintaining the charachteristics we want in espresso - namely, viscocity & high sweetness.
   
   
2. Our colormeter, a Lighttells, measures consistently within the small window of allowance that we set for each coffee. For filter roasts the windows are usually +/- 1 and between 95 and 105. 
   
   
3. Coffees have high solubility and extract evenly. 

How we acheive this success

• Our espresso roasts are usually between 11 minutes and 13 minutes in total roasting time. The reason we roast them longer than filter coffee is that we want the coffee more soluble and the acidity reduced a little. 
  
  
• Evenness of roasting is crucial and this is aided by the ability to control drum speed. Starting slow and gradually increasing the drum speed through the roast has aided us in controlling our espresso quality for years. 
  
  
• Espresso roasts have a development time (time after crack) of between 1:15 to 2 minutes.
  
  
• We aim to have an increase from crack temperature of around 10*C (+/- 2*C).