How to Store Bacteriostatic (BAC) Water Temperatures, Do's & Don'ts, vialcase.com MUST READ , You can only use bac water to mix peptides no exceptions, You must put it in the refrigerator immediately and keep it there only time you take it out is when you are using it and How to Store Bacteriostatic Water Safely Confused about whether BAC water needs refrigeration after opening? According to USP standards and Pfizer's own guidance, both room temp (2025C) and refrigeration are acceptable Keep water in your refrigerator save water AND energy! Sustainability