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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: sre on November 03, 2020, 04:08:56 PM

Title: Modifying the pH of a solution containing lemon juice
Post by: sre on November 03, 2020, 04:08:56 PM

This isn't school related but I figure it's undergrad level chemistry. Sorry if this is the wrong forum.

I'm trying to create a cocktail using Empress 1908 gin and lemon juice. Empress gin is colored with butterfly pea blossoms and is a deep blue color. Normally, adding lemon juice or a similar acid will change the color to pink. I've been told that this change doesn't happen if the pH of the solution containing the gin is over 4.0. Lemon juice seems to be in the 2.2-2.4 range. Would it be possible to add baking soda to the solution to raise the pH above 4.0?

Further, the cocktail I'm making is a milk punch which requires curdling the milk before putting it through a filter. I've read that milk curdles at pH 4.6 so I'd want to keep my pH level between 4.0 and 4.6. I have very little knowledge of applied chemistry so I'm at a loss as to how much baking soda I should use to achieve this level.

Title: Re: Modifying the pH of a solution containing lemon juice
Post by: Borek on November 03, 2020, 07:18:27 PM

Broadly speaking the best approach is to check the amount of required base experimentally. Note that the lemon juice is a natural mixture and doesn't have well defined composition, so what works for one lemon may not work for another.

Question is whether after adding bicarbonate cocktail will be still drinkable. With a food grade bicarbonate cocktail won't get toxic, but the taste can get disgusting, hard to say without trying.