Dosing and distribution techniques vary wildly from barista to barista, however, there are some generally accepted guidelines that will ensure that you are making the most of your time.
Dosing refers to the act of grinding the appropriate amount of coffee grounds for the coffee you are preparing.
Distribution is the way in which this coffee settles in the basket before it is tamped, positioned in the machine and extracted.
This is probably the most crucial and most pressing of issues relating to dose – especially if you are looking to save money.
Only ever dose the amount of coffee required for the amount of beverages you are making. Dose one coffee or one single extraction of espresso at a time before returning to your grinder to dose the next coffee. Do not pre-emptively dose the amount for two, three or four coffees and hope to get the right amount in the basket at each time.
By dosing one coffee at a time you ensure the coffee remains fresh and full flavoured. Coffee is a natural product and when ground it is exposed to the elements, mainly oxygen, and this creates a reaction.
Chemical processes occur in which the gases of the coffee are released as it oxidizes. This results in less flavour, less consistency in extraction times, less taste and more wastage.
Scales are your friend – you can easily acquire a cheap set of electronic scales for less that $25, tare your porta-filter and measure the precise amount of coffee that you are dosing. If you are over dosing (example: 28grams instead of 23grams) then you know you need to grind for a few seconds less than you did previously.
Distribution is a complex technique to some but can be very simple once you understand what is it you need to accomplish.
Once the coffee is dosed correctly, you may witness a mound of coffee grounds cascading over the top of your basket. This is not ideal. A lot of baristas either use their fingers to swipe of the excess coffee, tamp the coffee as it lies and simply extract the shot of espresso in the fastest, most inconsistent way. This is not recommended.
What is recommended is that you give the porta-filter a slight vertical tap as the coffee is ground into the basket. This will naturally compact the coffee and allow you to achieve the desired dose without any excess or overhang. If the dose is still a few grams too high, simply grab a spoon or other instrument and remove the excess grams before the coffee is tamped.
We have found this to be the most hygienic and most effective way of distributing coffee grounds. It is a repeatable process that is sure to improve the quality of your beverages. Once again, remember to weigh in and weigh out if you are unsure of how much coffee you should be dosing.
Have fun with it, experiment and see what works best for you. However, if you take these tips on board you are at a huge advantage already. Enjoy!