We study how concentrated emulsions elastify, or become increasingly elastic, through droplet rupturing induced by a strong applied shear. To do so, we have developed a novel method, sinusoidal amplitude variation (SAV) rheometry, for probing the emulsion's frequency-dependent storage and loss moduli during the emulsification process. A discrete number of high strain amplitude sinusoidal oscillations at a fixed frequency, which cause droplet rupturing, are followed by frequency sweeps at purturbative strain amplitudes which probe the impact of the rupturing on the moduli. We show that the plateau elastic modulus of a concentrated emulsion grows rapidly after only several oscillations and saturates after many oscillations. We measure how the yield properties of emulsions change during emulsification, and show that a critical rupturing strain must be exceeded in order for the emulsion to elastify. The rapid increase in the elastic modulus and subsequent saturation as a function of the number of driving oscillations point to a mechanism of positive feedback in emulsification that is cutoff by local nonaffine shear. (C) 2003 The Society of Rheology.