Why Choose Fast-Acting Saf Instant Yeast?. Indulge your passion for baking with Fast-Acting Saf Instant Yeast, one of the most revered yeasts in the world. Its user-friendly, fast-acting formula simplifies the baking process, making it easier than ever to create perfect artisan loaves, delicious pizza, fluffy sandwich bread, and mouthwatering bagels without the added hassle of proofing.