People often ask us how we go about profiling and dialling in a new coffee for the subscription. Below is a quick recap on how we dialled in June's Amoret El Salvador on filter to get the Dialled In settings. We use this same approach for each subscription coffee each month and publish our results.
Step 1 - Educated Guess
The first thing we do is use our experience to pick up on some of the clues about the coffee and the roaster. Based on the bean and the origin, coupled with the roaster's style allows us to have a pretty good idea where to start with the grind settings.
Here we decided that the coffee was slightly darker and therefore was going to need a slightly coarser grind than we typically start with. We chose 4.5 (note, 4.0 on the EK43 is typically where we begin for testing a filter coffee).
Step 2 - Test Settings
We brewed the coffee in the Aeropress to our chosen recipe and in this case, we were pretty close but the grind size was too fine meaning that the coffee over-extracted and it was also too strong. You could taste that in the cup as the bitterness overpowered the flavours and sweetness that were waiting to be released.
Step 3 - Change Settings
The next steps are where the knowledge from the SCA courses we've been taking really comes into its own.
The coffee was too strong as well as over extracted, so we decided to reduce the strength first.
To reduce the strength, we decided to reduce the coffee to water ratio (to effectively produce a more diluted cup). We did this by adding an additional 25ml of water to our recipe.
We brewed the coffee again with the new recipe and found that our coffee strength had reduced down from 1.40% TDS to 1.24% TDS - which was spot on.
Next, to reduce the extraction we decided to use a coarser grind size (meaning less contact surface for the water to extract the coffee from the grounds). We chose to change the grind size from 4.5 to 5.0 on the EK43.
However, if you just reduce the grind size you will end up with a weaker coffee (as it won't be able to extract as many solids from the coffee grounds, leading to a lower TDS).
Therefore, to overcome this potential reduction of strength you need to add more coffee to the recipe... and we decided to add an extra 0.5g of coffee.
Step 4 - Test Final Settings
Once we'd calculated the settings we wanted, we brewed the coffee again.
We found that the coarser grind size and the recipe change had allowed us to reduce the extraction from 22.50% to 21.50%. This now put the coffee in the SCA 'Golden Cup' square, and you could taste the results as the bitterness and heavy body had been replaced by the boozy flavours and sweetness.