The invention relates to a method for monitoring a reaction and to a reaction system which are inexpensive, compact, easy to implement, and enable the reaction medium to be fully supervised throughout the entire experiment. For this purpose, the invention relates to a reaction system, in particular for microorganism cultures, including: at least one vessel (M1) for the reaction medium (1, 1'), which is in fluid communication with an injection tube (10)； at least one vessel (F1) for a carrier fluid (11) that is immiscible with the reaction medium (1, 1'), which is in fluid communication with a reaction tube (20)； the injection tube (10) being mounted so as to lead into the reaction tube (20) such that individual drops (30) of the reaction medium can be injected into the reaction tube (20) and into the immiscible carrier fluid (11), so as to form a train of reaction chambers； at least one detector for monitoring a reaction； a means for classifying the reaction chambers； and at least one means for recirculating reaction chambers in front of at least one detector for monitoring a reaction.
