The same volume of beans and ground coffee weigh differently across different blends and roasts because of varying density, moisture and oil content. Small changes in the brewing process can make big differences to coffee taste and aroma, and with speciality coffee now the benchmark there is one thing every barista seeks: consistency.
The starting point is to identify the correct weight of coffee – any variation will create a difference in taste. Busy coffee shops brew different blends of coffee and use different grinders, scoops and other necessary tools while working at pace to fulfil orders. To add to this some baristas will use their hand or fingers to brush away excess coffee from the top of the portafilter while others will not. The only way to avoid these inconsistencies is to weigh doses from the coffee coming out of the grinder, and the amount of espresso coming out of the machine, everything should be weighed.