Starting in April, US coffee roasters had already been cut down on incoming supplies. But it wasn't until Nov. 29th that full citizen rationing had to occur. The initial rationing limited coffee to 1lb every 5 weeks, with a 10lb/year cap, per person over 15 years old. This was later to be increased even more, limiting people's access to the world's most precious commodity.
The Nov 30th issue of Life magazine covered all the various ways to "stretch" your coffee. Reducing your grounds-to-water ratio, "double dripping" your coffee, filling your cup half way instead of full... even adding fillers like chicory were recommended. Diners no longer could offer refills on coffee, and we can only imagine that an already depressed country moved one step closer to breaking. It only lasted until July 28th, 1943, the first item to be removed from rationing, even though some rationing didn't end until as late as 1947.
During this time South America had been experiencing bumper crops of coffee production due to increased demand around the world, and especially in the U.S., as coffee had become the drink of choice for most Americans. The Ink Spots had released their hit song "Java Jive" (see below for link), and even First Lady Eleanor Roosevelt was on board the java train with her weekly radio show "Over Our Coffee Cups" sponsored by the Pan American Coffee Bureau. In this radio broadcast the world got to listen to the First Lady's views on current events, while heavily pushing the value of coffee to the country and the War Effort.
Rationing was not put into effect due to lack of supply, in most cases. Rationing was, however, in place to regulate delivery of these products making sure that the military had first pick of whatever they needed. It was crucial that regular supplies made it to the front lines, and so regulation was needed to make sure that the supply lines went uninterrupted. In a time when ship transports were constantly at risk of German U-Boat attacks, all international shipping was high-risk business.
Over Our Coffee Cups Transcript:
Java Jive by the Ink Spots
Life Coffee Rationing tips
Coffee Rationing Coffee Crossroads