Acidity in Drinks

If you mix 100 grams of citric acid with 100 ml of water, you will not get 200 ml of solution; you get somewhere around 160 ml, just like simple syrup, but how much acid is in a mL of the solution and what is the total acidity in the drink? Unless you like math, that's a question you probably don't want to solve, so I've done it for you, in a smarter way. When you want to make an acid solution that you can accurately measure how much acid is in your drink, this is the way to do it.

I'm currently working on an online calculator to help you determine your acid solution concentrations with relation to the size of a drink. What works for a 4 oz cocktails doesn't necessarily work for a pint of soda. But the info and table below will get you started and I should have a calculator done in a week or so. 

Acid Solution No.1

This works for any of the three acids in the video. If you were to make a 120 ml (4 oz) drink, like a shaken cocktail in a 5 oz coupe, with some space and wanted to hit that 1.25% acidity mark, you'd use 3.0 ml. Or if you wanted to increase the acidity of a drink by 0.1% you would add 5 drops.

Instructions

60 g Citric Acid or Malic Acid or Tartaric Acid
Distilled Water

Place 60 grams of acid into a 120 ml dropper bottle. Add water—distilled preferred but tap water will work—to fill the bottle up to 120 mL. Shake to dissolve the acid.

Useage:

To use this table, with the above acid solution, determine your estimated drink size (top row, currently 4 oz or 8 oz drinks) but let's say a 4 oz cocktail and then go down the column until you see the acidity level you want, let's say 0.42%. Then move your eyes to the left column and you will see you need 1 mL of the solution is required to get a drink with that level of acidity. 

Obviously, if you have used an ingredient with acid already, you will just be increasing the amount. But this is great if you find a drink to flabby and just want to brighten up the acidity. 

Buffering Agents

Typically, you can add these buffering salts at any quantity, up to an equal amount of acid. However, many of the salts are not that soluble, for example potassium bitatrate (cream of tartar) has really low solubility at 6.1 grams per litre so you will get less than a gram dissolved in a 120 ml bottle. There are other options. 

Sodium citrate is readily soluble and combined with 

Citrate

Sodium Citrate 92 g/100 g H2O
Potassium Citrate
Calcium Citrate

It is best to avoid magnesium citrate as it is used as a laxative and even in small doses may cause some gastrointestinal discomfort.

Malate

Sodium Malate

Tartrate

Potassium Bitartrate (Cream of Tartar) is easy to find but has low solubility so you'll find that only 0.6 grams will dissolve in a 120 ml bottle (6.1 g/L). Though this is enough to change the acidity and flavour it can be more difficult to work with.

Potassium Sodium Tartrate is harder to find (look for Rochelle Salts) but much more soluble in water at 73 g/L. In a 120 ml bottle, you can dissolve up to 8 grams, allowing you flexibility in making your acid solutions.