The tape food is making through the fermentation process using yeast as a primary ingredient. A yeast supplement can be used to improve the fermentation process. In this study, the effect of garlic extract as a natural yeast supplement in making the yellow cassava tape was evaluated. A non-factorial completely randomized design with five treatments and four repetitions was performed as a research approach. The collected data were processed using an additive linear ANOVA model. The results show that a mixture with 3.0 g garlic extract highly improved the alcohol production for fermenting the yellow cassava tape. Based on the statistical analysis, Fcal (3.99) was higher than Ftab (2.90). The use of different garlic extract amounts exhibited a better improvement of the fermentation process than without the use of the garlic extract. An insufficient or excessive amount of yeast can affect alcohol production. Therefore, it is necessary to provide the exact garlic extract amount as the additional yeast supplement to produce cassava tape.