United States military chocolate Military chocolate has been a part of standard United States military ration since the original Ration D or D ration bar of 1937 . Today , military chocolate is issued to troops as part of basic field rations and sundry packs . Chocolate rations served two purposes : as a morale boost , and as a high - energy , pocket - sized emergency ration . Military chocolate rations are often made in special lots to military specifications for weight , size , and endurance . The majority of chocolate issued to military personnel is produced by the Hershey Company . When provided as a morale boost or care package , military chocolate is often no different from normal store - bought bars in taste and composition . However , they are frequently packaged or molded differently . The World War II K ration issued in temperate climates sometimes included a bar of Hershey ' s commercial - formula sweet chocolate . But instead of being the typical flat thin bar , the K ration chocolate was a thick rectangular bar that was square at each end ( in tropical regions , the K ration used Hershey ' s Tropical Bar formula ) . When provided as an emergency field ration , military chocolate was very different from normal bars . Since it was provided as a quick emergency food source , officials initially outlined that it should not be a tempting treat that troops might eat before they needed it . But even as attempts to improve the flavor were made , the heat - resistant chocolate bars never received rave reviews . Emergency ration chocolate bars were made to be high in energy value , be easy to carry and to withstand high temperatures . Withstanding high temperatures was extremely important , since infantrymen would be outdoors , sometimes in tropical or desert conditions , with the bars in their pockets against their bodies . These conditions would make any normal chocolate bar melt within minutes . Logan Bar or D ration . The first emergency chocolate ration bar commissioned by the United States Army was the Ration D , commonly known as the D ration . Army Quartermaster Colonel Paul Logan approached Hershey ' s Chocolate in April 1937 , and met with William Murrie , the company president , and Sam Hinkle , the chief chemist . Milton Hershey was extremely interested in the project when he was informed of the proposal , and the meeting began the first experimental production of the D ration bar . Colonel Logan had four requirements for the D ration Bar . The bar must : Its ingredients were chocolate , sugar , oat flour , cacao fat , skim milk powder , and artificial flavoring . Chocolate manufacturing equipment was built to move the flowing mixture of liquid chocolate and oat flour into preset molds . However , the temperature - resistant formula of chocolate became a gooey paste that would not flow at any temperature . Chief chemist Hinkle was forced to develop entirely new production methods to produce the bars . Each four - ounce portion had to be kneaded , weighed , and pressed into a mold by hand . The end result was an extremely hard block of dark brown chocolate that would crumble with some effort and was heat - resistant to . The resultant bar was wrapped in aluminum foil . Three bars sealed in a parchment packet made up a daily ration and was intended to furnish the individual combat soldier with the minimum sustenance recommended each day . Colonel Logan was pleased with the first small batch of samples . In June 1937 , the United States Army ordered 90 , 000 D ration or " Logan Bars " and field tested them at bases in the Philippines , Panama , on the Texas border , and at other bases throughout the United States . Some of the bars even found their way into the supplies for Admiral Byrd ' s third Antarctic expedition . These field tests were successful , and the Army began making irregular orders for the bars . With the onset of America ' s involvement in World War II after the attack on Pearl Harbor , the bars were ordered to be packaged to make them poison gas proof . The 4 - ounce ( 112 g ) bars ' boxes were covered with an anti - gas coating and were packed 12 to a cardboard carton , which was also coated . These cartons were packed 12 to a wooden crate for a total of 144 bars to a crate . Colonel Logan had specified that the D ration taste only a bit better than " a boiled potato . " This last requirement was imposed to keep soldiers from snacking on their emergency rations in non - emergency situations . As a result , the D ration was almost universally detested for its bitter taste by U . S . troops , and was often discarded instead of consumed when issued . Troops called the D ration " Hitler ' s Secret Weapon " for its effect on soldiers ' intestinal tracts . It could not be eaten at all by soldiers with poor dentition , and even those with good dental work often found it necessary to first shave slices off the bar with a knife before consuming . Tropical Bar . In 1943 , the Procurement Division of the Army approached Hershey about producing a confectionery - style chocolate bar with improved flavor that would still withstand extreme heat for issue in the Pacific Theater . After a short period of experimentation , the Hershey company began producing Hershey ' s Tropical Bar . The bar was designed for issue with field and specialty rations such as the K ration , and originally came in 1 - ounce ( 28 g ) and 2 - ounce ( 56 g ) sizes . After 1945 , it came in 4 - ounce ( 112 g ) D ration sizes as well . The Tropical Bar ( it was called the D ration throughout the war , despite its new appellation ) had more of a resemblance to normal chocolate bars in its shape and flavor than the original D ration , which it gradually replaced by 1945 . While attempts to sweeten its flavor were somewhat successful , nearly all U . S . soldiers found the Tropical Bar tough to chew and unappetizing ; reports from countless memoirs and field reports are almost uniformly negative . Instead , the bar was either discarded or traded to unsuspecting Allied troops or civilians for more appetizing foods or goods . Resistance to accepting the ration soon appeared among the latter groups after the first few trades . In the Burma theater of war ( CBI ) , the D ration or Tropical Bar did make one group of converts : it was known as the " dysentery ration " , since the bar was the only ration those ill with dysentery could tolerate . In 1957 , the bar ' s formula was changed to make it more appetizing . The unpopular oat flour was removed , ' non - fat milk solids ' replaced ' skim - milk powder ' , ' Cocoa powder ' replaced ' cacao fat ' and artificial vanilla flavoring was added . It greatly improved the flavor of the bar , but it was still hard to chew . Hershey bars . It is estimated that between 1940 and 1945 , over 3 billion of the D ration and Tropical Bars were produced and distributed to soldiers throughout the world . In 1939 , the Hershey plant was capable of producing 100 , 000 ration bars a day . By the end of World War II , the entire Hershey plant was producing ration bars at a rate of 24 million a week . For their service throughout World War II , the Hershey Chocolate Company was issued the Army - Navy ‘ E ’ Award for Excellence for exceeding expectations for quality and quantity in the production of the D ration and the Tropical Bar . Their continued efforts resulted in four stars being added to their pennant signifying the five times they received this distinction . Postwar to modern day . Production of the D ration bar was discontinued at the end of World War II . However , Hershey ' s Tropical Bar remained a standard ration for the United States Armed Forces . The Tropical Bar saw action in Korea and Vietnam as an element of the " Sundries " kit ( which also contained toiletries ) , before being declared obsolete . It briefly returned to use when it was included onboard Apollo 15 in July 1971 . " Congo Bar " / Desert Bar . In the late 1980s , the US Army ' s Natick Labs created a new high - temperature chocolate ( dubbed the " Congo Bar " by researchers ) that could withstand heat in excess of . During Operation Desert Shield and Operation Desert Storm , Hershey ' s Chocolate was the major manufacturer , shipping 144 , 000 bars to American troops in the southwest Asia theater . While Army spokesmen said the bar ' s taste was good , troop reactions were mixed and the bar was not put into full production . Since the war ended before Hershey ' s stores of the experimental bar were shipped , the remainder of the production run was packaged in a " desert camo " wrapper and was dubbed the " Desert Bar " . It proved a brief novelty but Hershey declined to make more after supplies ran out .