Sources:
Food amd War in Twentieth Century Europe, Edited by Ina Zweiniger-Bargielowska, Rachel Duffett, and Alain Drouard. Farnham, GB: Ashgate, 2012.
Other Resources:
http://www.instructables.com/id/ACORN-Coffee/
http://foragedfoods.co.uk/how-to-make-acorn-coffee/
http://www.studentpulse.com/articles/899/3/the-british-blockade-during-world-war-i-the-weapon-of-deprivation
Image of German ersatz coffee in original package from https://www.awm.gov.au/blog/2010/07/12/nothing-like-the-real-thing/