What Bacteriostatic Water is, in plain English.
Bacteriostatic water is sterile, non-pyrogenic water with 0.9% benzyl alcohol added as a preservative: 9mg in every millilitre. Benzyl alcohol is a simple aromatic alcohol (C7H8O, CAS number 100-51-6) that occurs naturally in many plants and essential oils. At this concentration it stops bacteria from multiplying without sterilising the water outright, which is what 'bacteriostatic' means. That is the property that separates it from plain sterile water: a vial can be drawn from more than once over a limited period, where sterile water with no preservative is discarded after a single use. 'Non-pyrogenic' means it is free of the bacterial fragments that can survive sterilisation and cause fever reactions. In research settings it is the standard diluent for reconstituting freeze-dried peptides: the powder in every other vial in this range is dissolved in it before use, and it is the one item here that is not a compound in its own right. Supplied as a 10ml vial; store at 2–8°C in line with the rest of the range.
