My family has made and enjoyed a spicy, cheesy, Mexican dip for as long as I can remember. Recently, my family was going to make some of the dip for dinner, but the store did not have any of the bricks of processed cheese that are a major component of the dip.
Without any other options, I decided to turn this meal into an experiment as I attempted to make the processed cheese from scratch. Here is how that venture unfolded.
What is Processed Cheese?
In order to make the cheese, I first had to understand what the processed cheese really was. Processed cheese is simply cheese that has some additives that essentially emulsify all of the constituents of cheese, such as the proteins and the insoluble calcium phosphate.
Sodium citrate is usually the emulsifying agent that is used to make processed cheese; this causes the cheese to melt into a smooth and homogeneous blend rather than the greasy, stringy mess that is a characteristic of melted cheese. Think of American cheese versus mozzarella.
While stringy cheese might be ideal for pizza, it isn’t ideal for a dip; I don’t exactly want the entire batch to cling to itself and break off every chip that I attempt to dip into it. This is where the processed cheese comes in: it allows the dip to be smooth and easily scooped up by chips.
What is Sodium Citrate?
As I mentioned earlier, the store did not have any bricks of processed cheese, therefore, I had to process my own cheese. I remembered back to a video that I had seen about a year ago in which the author stated that it is possible to process your own cheese using lemon juice and baking soda.
Lemon juice and baking soda? Those ingredients sound like homemade cleaning supplies!
Yes, they do; I thought the author of that video was nuts for a moment, until I realized there was a chemical reaction taking place. Lemon juice is acidic and baking soda is basic, making the reaction an acid-base reaction.
I’m sure you have mixed baking soda and vinegar at some point in your life; it is one of the easiest and safest acid-base reactions that you can perform, which uses only kitchen supplies. In that reaction, you are reacting acetic acid (vinegar) with sodium bicarbonate (baking soda) to produce sodium acetate, water, and carbon dioxide.
The only difference between the two reactions is that lemons do not contain acetic acid, instead, they contain citric acid.
Wait a minute, lemons contain citric acid, and baking soda contains sodium, does that mean that, when lemon juice and baking soda react, they produce sodium citrate?
This is the question that raced through my mind after watching the video, and I soon realized the answer was yes. Sodium citrate is merely the sodium salt of citric acid.
Making Sodium Citrate
I started by juicing 3 medium lemons. I really should have strained the juice to remove the seeds and pulp before pouring the juice into the pan, but I realized this too late and I strained the juice in a later step.
Then, I sprinkled some baking soda onto the juice and stirred the solution until all of the baking soda had dissolved and reacted; I repeated this step until no more bubbles were formed when baking soda was added (this indicates that all of the citric acid has been used up).
The reaction of citric acid and baking soda produces sodium citrate, water, and carbon dioxide. Here is the reaction equation:
H3C6H5O7 (aq) + 3 NaHCO3 (aq) -> Na3C6H5O7 (aq) + 3 H2O (l)+ 3 CO2 (g)
I decided to simmer the solution until it had been reduced to the point of being a slightly thick liquid.
I found it interesting how the liquid became bright yellow. This is due to some organic pigments from the lemons that somehow survived the process; I believe these are called carotenoids.
Breaking one of the cardinal rules of chemistry, I tasted the solution to see if it still tasted like lemons or if a reaction had occurred. This was all right because the chemicals used were all food ingredients and the products were also edible chemicals, however, I wouldn’t recommend making a habit of tasting chemistry experiments.
The solution tasted nothing like lemons, in fact, it was bitter. It has the slightest salty flavor with a bitter taste somewhere between that of baking soda and Epsom salt. Yes, I have tasted both of them out of curiosity; if you taste them, just make sure they are food grade.
Making the Processed Cheese
I was unable to find the original video again, but I made the processed cheese loosely based on a couple different recipes and my memory of that video.
I heated 3 pounds of cheese in a pan and added the homemade sodium citrate solution once the cheese started to melt. I also added some milk until the texture was desirable.
The sodium citrate did cause the cheese to be much less stringy, however, I think I should have at least doubled the amount of lemon juice that I used. I would recommend using more lemon juice, or even buying food grade sodium citrate and adding maybe up to one teaspoon per pound of cheese, depending on the desired texture.
I added this mixture to my dip, and stirred it in. The result was very delicious and I would definitely try this again if I needed to, however, it is much easier to just buy the cheese in the first place.
Have you ever tried this? How was your experience?
Onward American 