Phosphoric acid guidelines?

matthewzuras

Hello!

I'm pretty new to ChefSteps and this is my first post, so forgive me if this has been addressed elsewhere.

I got some food grade 75% phosphoric acid for the cherry cola and fruit juice soda recipes, and Now that I have about a quart of the stuff, I'm eager to know some general guidelines for how much to add to other beverages like cocktails. E.g, 2% of total weight? .2%? .0002%?

Despite reading its kinda-scary safety data sheet, I've managed to convince myself that phosphoric won't kill me if I use it properly, so I'm just looking for a safe range to experiment without the risk of burning a hole in my esophagus.

Any help is appreciated!

Chris_Young_80640

@MZ — The most important use of any acid is controlled by the pH. You want to add enough that the beverages is pleasantly tart. Generally, you will acidify in the range of 2.5 to 4+. Keep in mind the pH scale is logarithmic, which means pH 2 is 10x more acidic than pH 3, and 100x more acidic than pH 4. Point being, pH in the twos is really low. 

Most food or sufficiently complex beverages have some degree of buffering capacity (the ability to resist a pH change when adding an acid) that makes it difficult to predict how much a given weight of acid will actually shift the pH. So working with litmus paper or a pH meter is really the way to be consistent.

All of this said, working by taste is not a horrible way to go, and it's not hugely unsafe. If something tastes pleasantly tart, you're often around pH of 2.8 to 3.3 to my palate, and that is often as much as a few percent acid by weight.