subject: Sensory Evaluation – what is it? [print this page] All the contents of the flask are then discharged by passing them through a condenser. It is in the condenser that these contents are actually distilled in a distillation tube. The solvent toluene remains t the tom as it is immiscible while water is seen to remain in the bottom phase of the tube. The solvent is then made to return to the original flask that contained it with the help of an inclined tube that is linked between the fractioning column and the burette or distillation tube. Then the quantity of the water is measured using a graduated burette and then, proportionally, the percentage of work value is calculated.