Experiments

Homemade ricotta experiment

I found a recipe for making ricotta at home with lemon juice. I assumed the lemon juice was added for its acidity, this makes the proteins in the milk clump together. This would mean that other acid products would have the same result if used on the same milk. To prove this hypothesis I did an experiment attempting to make ricotta with vinegar, lemon juice, and cola.

Now ricotta made with cola sounds kind of gross, but I’ve always heard that mixing cola with dairy clumps in your stomach. (I always heard this in relation to drinking alcohol, and then those people blame throwing up on mixing cola and dairy) Therefore I was curious if it was possible to make more ricotta with cola because it should be such a strong reaction.

My experiment setup:

Materials:

  • pan
  • wooden spoon
  • 3 jars
  • pH-paper
  • measuring spoons
  • cheese-cloth
  • sieve
  • 3L full-fat Dutch milk
  • 1.5 teaspoon salt
  • juice of half a lemon (turns out to be 21 mL)
  • red wine vinegar (so also 21 mL)
  • cola (and also 21 mL)

 

Method:

Bring 1 L milk with 0.5 teaspoon salt to a boil.

Decrease the temperature and add an acid.

Keep heating and wait until a layer of solids come floating up.

Remove the pan from the heat and let it rest for 10 min.

Put the cheese-cloth in the sieve and use this combination to separate the solids from the liquid.

Gently push the fluids out of the ricotta.

Put the ricotta in a jar

Repeat for all the acids.

 

Results

My first attempt was with lemon juice and that went perfectly fine. I had a yield of 33 grams of ricotta. I wanted to use the same amount of vinegar and cola, so I measured how much lemon juice comes from half a lemon. To make the comparison complete I measured the pH of the acids I used and the combination of the acid with the milk.

Lemon juice ricotta experiment summary

I tried to repeat this amazing result with red wine vinegar. The combination in the pan looked promising at first. But, this gave less than perfect results. I only was able to yield 2 grams of ricotta. Then I tried adding more vinegar (100 mL), to make the combination more acid. This gave me 10 grams of ricotta more.

Red wine vinegar ricotta
Red wine vinegar ricotta

Finally, with cola, nothing happened. I was not able to get any ricotta out of the combination of milk with cola. I started with adding the 21 mL, then another 100 mL until I finally added the entire can of coke. This result is completely opposite of what I expected. So I started googling and I came across this video. In this video and all the articles showing the same a little bit of milk is added to a bottle of cola, whereas in my experiment a bit of cola is added to a lot of milk.  So my hypothesis regarding this issue is that a mix of milk and cola will curdle, but only if a certain threshold is reached. Now I will think of a nice experimental plan for this and post it in the future.

Cola and milk drink
Cola failure

Some food chemistry background:

Milk is a buffer solution, meaning that the pH is rather constant due to the weak base in the liquid. For a proper background on buffers, I recommend you to check khanacademy. I know I’ve used that website for help on so many of the courses I took. Anyhow, what it means is that much acid is needed to change the pH of the milk. 

Now lemon juice, vinegar, cola, and milk are all buffer solutions. The difference between the lemon juice, vinegar and cola is the level of buffer capacity. The pH of the three acids is all between 2 and 3, I cannot measure it more precisely with the equipment I have. So, for now, the conclusion of this experiment is that lemon juice is the strongest buffer of the three acids.

The practical conclusion of this experiment is that ricotta is best made with lemon juice.

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