The [1.1.1]cryptand is a proton sponge able to change slowly and almost linearly the pH of a solution (range 4–10) in such a way that it can be used as a chemical device in the automatic control of a variety of pH-sensitive processes under variable-pH conditions. A simple mathematical model describing its behaviour, based on the fundamental work by Lehn's group, and computer simulation carried out for different values of concentration and starting pH (in agreement with produced experimental data) enable the visualization of the pH-time profiles for any possible experimental conditions and provide directions for its use as a molecular burette. The interference with species present in the reaction vessel and acting as buffers is also discussed and measures are suggested for avoiding problems.