|What is it?||An inexpensive white crystalline alpha hydroxy acid.|
|Appearance||White crystals; looks like table salt or white sugar.|
|Usage rate||It depends. If part of bath bombs or other “fizzing” products it can be used upwards of 25%. If being used as a pH adjuster it is used at significantly lower rates (less than 1%).|
|Why do we use it in formulations?||In bath bombs and other fizzing products it forms all or most of the acidic part of the reaction that causes the fizz. It can also be used to lower the pH of products as part of a 50/50 solution of citric acid and distilled water.|
|Do you need it?||I’d recommend it; it’s an accessible and inexpensive acid that doesn’t have the characteristic smell of vinegar.|
|Strengths||Highly effective, inexpensive acid.|
|Weaknesses||I can’t think of any that aren’t inherent to strong acids (potential to be irritating, sour tasting, etc.).|
|Alternatives & Substitutions||In bath bombs it’s very difficult to adequately substitute citric acid. I have no suggestions at this time.
For pH adjusting a lactic acid solution is a good alternative.
|How to Work with It||In bath bombs and other primarily powdered fizzing products, include citric acid with the rest of the powdered ingredients.
For pH adjusting, create a 50/50 solution of citric acid with distilled water and use single drops to adjust the pH, re-checking the pH between additions.
Take care not to inhale.
|Storage & Shelf Life||Stored somewhere cool, dark, and dry, citric acid should last at least three years.|
|Tips, Tricks, and Quirks||Citric acid is an alpha hydroxy acid along with acids like lactic and glycolic.|
|Recommended starter amount||If you want to make bath bombs I’d start with at least 500g (1lb). If it’s just for pH adjusting 30g (1oz) will be more than enough.|
|Where to Buy it||Buy it from an online DIY ingredient supplier or Amazon.|