Surprise has been expressed in some quarters at the amount of coffee that I drink while writing my Victorian Detective series. Lest it be thought that I spend all day sitting in front of a laptop, mainlining caffeine, I probably need to point out that the coffee cup: word count ratio also includes other writing-related activities that may take place at different times of the day and in different places but can include coffee as part of the journey.
For a start, there is thinking/planning coffee, which happens while counting the fish in the pond, re-arranging various drawers, reading the paper, de-frosting the fridge or moving objects upon the desk. Okay, I call it thinking/planning coffee, but let's be gut-honest, you know, and I know you know exactly what it is.
There is also research coffee. Research is something most writers do, especially those who write historical fiction, because every little detail has to be absolutely accurate. You can wing it, but sod's law dictates that if you do, your book will fall into the reviewing hands of the one and only world-expert in the winged area, and they will take great delight in exposing your ignorance to the wider reading public.
I use two sources for research: the internet, which is brilliant for very specific information: Victorian funerary practices, the acceptable length of mourning for different family members etc. However I also like to get out and use the local library, because there is something about the serendipity of working along the shelves and discovering something you didn't know you needed until you came across it. It's a bit like Topshop, but with books. I once found a whole page on how the Victorians decorated their Christmas trees in a book on Celebrations - and used the information in Diamonds & Dust.
Both research sources involve copious amounts of coffee naturally, although the best thing about extra-mural research coffee is that it is usually accompanied by research cake. Victoria sponge cake, of course.