Two methods are commonly used, the "Colloid mill" method and the "High Internal Phase Ratio (HIPR)" method.
tˈuː mˈɛθədz ɑːɹ kˈɑːmənli jˈuːzd, ðə "kˈɑːlɔɪd mˈɪl" mˈɛθəd ænd ðə "hˈaɪ ɪntˈɜːnəl fˈeɪz ɹˈeɪʃɪˌoʊ hˈɪpɚ" mˈɛθəd.