It was not always so. Early Grand Prix cars ran on a fierce mixture of powerful chemicals and additives, often featuring large quantities of benzene, alcohol and aviation fuel. Indeed some early fuels were so potent that the car's engine had to be disassembled and washed in ordinary petrol at the end of the race to prevent the mixture from corroding it!
Over the years more and more regulations have been introduced regarding the composition of fuel, a move driven in part by the oil companies' desire to have demonstrable links between race and road fuel.
The modern fuel is only allowed tiny quantities of 'non hydrocarbon' compounds, effectively banning the most volatile power-boosting additives. Each fuel blend must be submitted to the sport’s governing body, the FIA, for prior approval of its composition and physical properties. A 'fingerprint' of the approved fuel is then taken, which will be compared to the actual fuel being used at the event by the FIA's mobile testing laboratory.
Under current F1 regulations, each car is limited to 105kg of fuel per race and all of F1 racing's fuel suppliers engage in extensive testing programmes to optimise the fuel's performance, in the same way any other component in the car will be tuned to give maximum benefit. This will likely involve computer modelling, static engine running and moving tests.
The car's engine oil is also worth a mention. Not only does it reduce wear on components, but it also helps to perform a vital diagnostic role, being closely analysed after each race or test for traces of metals to help monitor the engine's wear rate.