A great many methods are available for the concentration of biosurfactants from microbiological media. The strongest known biosurfactant, surfactin, serves as a model in many studies, so is used here to illustrate the diversity in approaches to product enrichment. Common physiochemical properties mean that many of these methods can be applied to other systems. Although acid precipitation is the most commonly used form of enrichment, phase separation is both an intrinsic property of surfactants and a useful tool for biotechnology. Direct liquid partitioning, membrane ultrafiltration and foam fractionation can all be regarded as phase separation technologies.