If 100ml hot water is required to extract all the tea from a tea bag, then 100ml hot water is the optimum volume of the extraction solvent. Ten 10ml volumes of hot water are fractional volumes of an extraction solvent i.e. hot water. Each fractional volume of an extraction solvent can then be used to extract the tea from the tea bag in a single extraction cycle. To use all the ten fractional volumes of the extraction solvent it would need to carry out the extraction in ten extraction cycles. Should one opt to use 20ml of hot water to extract the tea from the tea bag, then the optimum volume of the extraction solvent, 100ml ought to be divided into five fractional volumes of an extraction solvent (hot water), each of which equals 20ml. The fractional volume of the extraction solvent of 20ml would then be used in each extraction cycle.