Measurements are available from NCHFP for using citric acid vs. bottled lemon or lime juice and one set of conversion measurements is given for vinegar vs. bottled juice. But there is no (to my knowledge) chart of conversion rates.

NCHFP says for canning tomatoes add two tablespoons of bottled lemon juice or 1/2 teaspoon of citric acid per quart of tomatoes. So 1/2 tsp citric acid = 2 T bottled juice.

For pints, use one tablespoon bottled lemon juice or 1/4 teaspoon citric acid. So 1/4 tsp citric acid = 1 T bottled juice.

Four tablespoons of a 5 percent acidity vinegar per quart may be used instead of lemon juice or citric acid. However, vinegar may cause undesirable flavor changes. So 4 T vinegar = 1/2 tsp citric acid = 2 T bottled juice.

Dave

I read the following in "Putting Food By" and have been wondering about it, in general, so this thread might be a good opportunity for me to toss it out and get some thoughts on it.

To... make a 5-percent solution of citric acid... [dissolve] 2 tablespoons fine citric acid in 1 [US] pint (2 cups) of boiled water; or, if you want to be metric, dissolv[e] 30 ml of fine citric acid crystals in 1/2 litre (500 ml) of boiled water. Either translation will produce a solution around 6 percent instead of 5 -- but the result will serve the purpose we're after." [Janet Greene, Ruth Hertzberg, Beatrice Vaughan. Putting Food By. New York: Penguin. 2010. Page 40.]

Seems it potentially might be a way to add an acid liquid to a recipe, without adding a vinegary taste (or maybe it does have a taste, I don't know.) Aside from the obvious (white vinegar easier to get than citric acid powder), I have been wondering in the back of my mind why the people at Washington State (Doughtery and Hillers) who developed a lot of the salsa recipes didn't consider it, I gather there is some end user resistance to their recipes because of the vinegar taste. Not saying I agree with the resistance one way or the other. Not even saying I agree with my own thoughts on any of this, lol. And I'm not advocating any approach or substitution.

Just honestly tossing it about because I have wondered about the citric acid liquid in the back of my mind. (And come to think about it, I also wonder why boiled water...)