Actually ! this happened by mistake but nevertheless it was an intriguing find. I came up with an image of photographying coffee beans inside a portafilter holder and thought wow ! that looks lovely – the hard steel metal look contrasting nicely with lovely dark brown freshly roasted Indian Malabar Monsooned coffee beans, below
However, as I was just about to make coffee, surprise ! surprise ! I thought let me throw the beans from my photo shoot into the grinder and voila ! or should I link Italian to my double espresso offering and say Prego (as in ready to be served) the coffee beans were exactly the same quantity I needed to make my afternoon dose of Doppio (double espresso in English).
Take caution ! make sure that your portafilter holder, which should always sit inside the machine nice and hot for the next shot is dry, if not you will wet the beans and extract some precious locked up flavour – and also make sure you put the beans quickly into the coffee grinder as you don’t want any unnecessary heat on your coffee beans. I’m not sure if I am the first to discover this and I am probably not, but I thought wow ! what a great find, especially as if you don’t have a doser on your coffee machine that tells you how much to grind for a single or double espresso. 
This “new” method can be helpful if you are always having to guess how much to pour from bag into grinder and usually fall short or grind too much, which if you are a purist like me, will go to waste as I don’t save already ground coffee for another espresso, unless I am pulling another shot within a few seconds. Some experts say that the taste of the coffee begins to go after 12 seconds of grinding – so hurry up and try this out.
From Coffee With Love 