Home Cosmetic Science Talk Formulating potassium sorbate at a slightly higher pH (~5.2)


  • potassium sorbate at a slightly higher pH (~5.2)

    Posted by Bluebird on July 19, 2023 at 2:49 am

    I’m eager to hear your thoughts and get any advice on using potassium sorbate as the only anti-mold/fungi/yeast preservative in water type formula at pH ~5.2, or, at the lowest, pH 5.

    I have anti-bacterial preservatives in the formula but they are not known to be much anti-MFY; for ex, 1,2 hexandiol.

    I read things that say that at pH 5, potassium sorbate is only effective to ~37% (https://lotioncrafter.com/products/potassium-sorbate).

    My starting concentration to test is 0.2% of potassium sorbate.

    Would love to hear your thoughts on whether this sounds likely to succeed or problematic.

    Perry44 replied 4 months, 3 weeks ago 4 Members · 5 Replies
  • 5 Replies
  • abdullah

    July 19, 2023 at 7:56 am

    Try to get at least 0.1% preservative in acid form by reducing pH, increasing quantity or adding another antifungal preservative too.

  • Perry44

    July 19, 2023 at 8:04 am

    I’d guess it would be unlikely to succeed. There is not enough salt in the acid form at pH 5. Why not go lower than that?

  • Bluebird

    July 19, 2023 at 8:53 am

    Okay, thank you both.

    I guess, following Abdullah’s advice, using pH 5 (which seems to lead to 37% activity, at least purportedly), and also increasing the concentration to 0.3% potassium sorbate would likely work, as it should lead to 0.111% in the active form. To @Perry44 I want to go low pH as you said for preservative reason but it seems one of my active ingredients is unstable at a low pH.

    • Perry44

      July 19, 2023 at 10:28 pm

      Which active ingredient?

  • philgeis

    July 19, 2023 at 1:17 pm

    Be esp. attentive to stability with sorbate

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