Tag: water

Water in Cosmetic DIYs

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Water

Aqueous Phase Standards & The “Water to 100” Logic

In my formulation studies, water is the most voluminous and technically volatile component. Because water supports microbial life, its purity and the logic behind its calculation are the primary safeguards for a stable product.

1. The Purity Hierarchy: Beyond the Tap

The choice of water is not negotiable. Standard tap water contains minerals (electrolytes) and metal ions that can destabilize emulsions and deactivate preservatives.

  • Demineralized Water: Free of minerals that interfere with electrolyte-sensitive ingredients (like Carbomers or specific emulsifiers).

  • Microbiologically Pure Water: Required to ensure we aren’t introducing bacteria or fungal spores into the batch.

  • The “Boil and Hold” Protocol: If commercially distilled, sterile water is unavailable, I utilize a high-heat mitigation strategy. I boil demineralized water for at least 20 minutes to reduce the bio-burden. This does not guarantee 100% sterility, but it significantly increases the efficacy of the final preserving system.

2. The “Heat and Hold” Method

When executing heated emulsions, I often utilize the Heat and Hold technique. This involves maintaining both Phase A (Aqueous) and Phase B (Lipid) at 70°C–75°C for 20 minutes.

  • Objective: To ensure all high-melting-point waxes are fully integrated and to provide a secondary thermal “kill step” for potential pathogens in the water phase.

3. The Mathematical Protocol: “Water to 100”

In professional formulation, we work exclusively in Percentages (%). This ensures that the concentration of active ingredients and preservatives remains constant, regardless of the batch size or substitutions.

Why we calculate water last:

By listing water as “Water to 100,” we treat it as a flexible solvent. If I decide to increase an active ingredient from 1% to 2%, I do not reduce my preservative; I simply reduce the water. This maintains the integrity of the chemical ratios.

Example Calculation: If a formula requires:

  • Gelling Agent: 1.5%

  • Preservative: 0.5%

  • Actives: 3.0%

The math follows:

If I substitute a gelling agent that requires 3.5% for the same viscosity, the math updates automatically:

Result: The preservative remains at exactly 0.5% of the total mass, ensuring the product remains safe.

Researcher Summary

“Water to 100” is the language of the cosmetic chemist. It allows for agility in the lab—permitting substitutions and adjustments without compromising the safety or performance of the final cosmetic. Remember: Where there is water, there must be a preservative.