This article argues for a revision of the theories and assumed production methods used in Hellenistic and Roman mosaic glass. Knowing how glass behaved in different circumstances under differing heat processes allowed for the possibility of experimenting and demonstrating the inconsistencies in many of the accepted explanations of mosaic production. Experiments were run to test new production ideas, contrasting the findings with previously suggested production methods. The findings bring into question many of the accepted hypotheses for mosaic production. The evidence and hypotheses formed from the experiments challenge many of the traditionally held ideas for the production of this glass and reinforce the need for experimental and practice-based approaches to this type of work.