So, what if the extraction is not looking good? As in
looking watery and a yellowish colour or really, really
slow and dark and dripping.
If the extraction is not as beautiful as it should be
then this is most likely due to the setting of the
grinder. The grinder would usually need a simple
correction, we call this calibrating the grinder or
dialling in your coffee. Coffee changes because of
environmental factors such as temperature, humidity
and age. When the coffee changes it will grind slightly
different resulting in a different extraction time.
A slow extraction could have two reasons:
1. grind is too fine
2. dosage is too high
The first step to check is always the dosage. You can
weigh the coffee to ensure your dosage is correct.
The exact dosage you are looking for will depend on
your recipe. Usually you are looking for something
like this:
• a single dose needs around 9 to 10 grams
• a double dose uses around 15 to 17 grams
Once you have your dosage weighed out, tamp the
coffee and run the shot. Time the shot to see how long it takes. If it takes too long
then the grinder needs to be set to a coarser grind. Once you have adjusted the
grind you need to purge the grinder with two double shots. After you have purged
the grinder you start again. So, weigh out the dose, tamp the coffee and time the
extraction. It is best to test the grind with a double shot only and ideally you take
the average extraction time of three shots. Check the manual of your grinder to find
out how to adjust the grind and the dosages.