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The Cheese Maker

April 22, 2010

We left off yesterday discussing why cheese happens, and the different types of cheese. Now it’s your turn! This lab is designed for 10th-11th grade chemistry, but can be used for younger kids too. I did the experiment last year with an old camera, so they’re pretty terrible quality. This is an educational post, not a pretty post! 😉

Lab: Demonstrating the Coagulation of Protein in Cheese Making

In this activity you will precipitate casein from milk using two different methods. This demonstrates the denaturing of proteins, coagulation, chemical reactions, and the effect of heat on those reactions

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Making cheese is one of the best ways to view how milk proteins behave and function. Cottage cheese is a fresh cheese that requires no ripening. It can be made with the enzyme rennin or with the addition of an acid. Home-made fresh cottage cheese is delicious and can be served in many ways. It is delectable with pomegranate seeds, cantaloupe, or sliced strawberries and raspberries. It can be enjoyed in savory applications with black pepper and additional salt, if needed. Cottage cheese can be layered with crushed pineapple, granola, and a dollop of whip cream for a parfait. It is a great source of calcium and protein- so take advantage of this lab and enjoy your cottage cheese!

Materials Required

  • Distilled white vinegar (acetic acid), 5% acidity
  • Rennet tablets
  • Pasteurized skim milk
  • Cheese cloth
  • Rubber bands
  • Stirring Rod
  • Heat-proof gloves
  • Weighing boats
  • Hotplate
  • Beakers
  • Graduated cylinder
  • Thermometer
  • Eyedropper
  • Hammer or tool for crushing
  • Heatproof pad

Safety: eyewear is always required in the lab and the students should be prepared to handle hotplates and warm milk. Scary!!

Procedure

Part one: Precipitate casein from milk using an acid.

1. Record the weight of 120 mL (1/2 cup) of milk and place it in a beaker.

2. Place the milk on a hotplate and heat to 21⁰ C, turn off the hotplate and remove the beaker.

3. Add 11 mL (2 tsp) of acetic acid to the warm milk and stir for 2 minutes, then allow the milk to sit for 5 minutes.

4. Cut a piece of cheese cloth (2-3 layers) large enough to cover the top and 2 inches down the sides of a beaker. Using a rubber band, secure the cheesecloth in place. Pour in the curdled milk into the beaker, collectin the curds and allowing the whey and vinegar to drain away.

5. Gather the cheesecloth and rice in cold water, either under gentle running water or by dipping in another beaker.

6. Squeeze until almost dry then spread out and let dry for about 5 minutes.

7. Scrape the cottage cheese from the cheesecloth and weigh the precipitate, recording your results.

Part two: Precipitate casein from milk using an enzyme

1. Crush half of one rennet tablet with a hammer or crushing tool.

2. Weigh 120 mL of skim milk and pour it in a beaker. Place on a hot plate.

3. Heat the milk to 43⁰ C, and then carefully pour the hot milk onto the rennet tablet. Stir for two minutes then allow to sit for 10 minutes

4. Secure cheesecloth on a beaker, as you did in the previous experiment and strain they curds.

5. Squeeze out the liquid from the curds and then spread out the cheese cloth. Let dry for 5 minutes

6. Weigh your precipitate and record your results

Compare the weight of the precipitate to the weight of the milk in both experiments, and compare the weight of the curds from experiment one and experiment two.

 

To make a more substantial amount of cottage cheese to enjoy as previously stated, follow this recipe:

Ingredients

  • 1 gallon pasteurized skim milk
  • 3/4 cup white vinegar
  • 1 1/2 teaspoons kosher salt
  • 1/2 cup half-and half-or heavy cream

Directions

Pour the skim milk into a large saucepan and place over medium heat. Heat to 120 degrees F. Remove from the heat and gently pour in the vinegar. Stir slowly for 1 to 2 minutes. The curd will separate from the whey. Cover and allow to sit at room temperature for 30 minutes.

Pour the mixture into a colander lined with a tea towel (or cheese cloth) and allow to sit and drain for 5 minutes. Gather up the edges of the cloth and rinse under cold water for 3 to 5 minutes or until the curd is completely cooled, squeezing and moving the mixture the whole time. Once cooled, squeeze as dry as possible and transfer to a mixing bowl. Add the salt and stir to combine, breaking up the curd into bite-size pieces as you go. If ready to serve immediately, stir in the half-and-half or heavy cream. If not, transfer to a sealable container and place in the refrigerator. Add the half and half or heavy cream just prior to serving.

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Use 250 mL of milk clip_image002[8]
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It was heated up to about 300 C

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4 tsp of vinegar were added. It was then stirred, the curds separated from the whey.

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The curd was strained and rinsed.

 

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The resulting precipitate was broken up.

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The curds resembled cottage cheese, then I added salt and half and half.

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The taste? Ohh Mom thought it was a thumbs down. Please note, she sampled the "lab version and not the recipe version. I didn’t tell her that, though! Shh. 🙂

 

 

Sources

"Chymosin (Rennin) and the Coagulation of Milk." arbl.cvmbs.colostate.edu. 30 Jan. 2009 <http://www.vivo.colostate.edu/hbooks/pathphys/digestion/stomach/rennin.html&gt;.

"IFT Experiments in Food Science Series." Access Excellence @ the National Health Museum. 30 Jan. 2009 <http://www.accessexcellence.org/AE/AEPC/IFT/unit_three.php&gt;.

Perdue Research Foundation. "Unit 3. Proteins." IFT Experiments in Food Science Series 3 (2000): 1-22.

"Quick Cottage Cheese Recipe : Alton Brown : Food Network." Food Network – Easy Recipes, Healthy Eating Ideas and Chef Recipe Videos : Food Network. 30 Jan. 2009 <http://www.foodnetwork.com/recipes/alton-brown/quick-cottage-cheese-recipe/index.html&gt;.

"What are proteins and what do they do? – Genetics Home Reference." Genetics Home Reference – Your guide to understanding genetic conditions. 30 Jan. 2009 <http://ghr.nlm.nih.gov/handbook/howgeneswork/protein&gt;.

The Visual Food Encyclopedia: The Definitive Practical Guide to Food and Cooking. New York: Macmillan, 1996.

~~~

So tomorrow at 5:00 AM I’m leaving on an air plane to Florida!! 😀 I’m not sure how the blogging situation will be, but hopefully I can find some internet access and get a post up.

Senior trip ‘10! Woo!

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11 Comments leave one →
  1. April 22, 2010 9:06 am

    Thanks for intrepidly exploring the world of cheese-making, May! It’s been so fun and informative to read these posts.

  2. Danielle permalink
    April 22, 2010 10:54 am

    Wow, cheese making is complicated lol. They sell vegetarian (aka vegan) rennet at my local store so I’m guessing it would be possible to make my own non-dairy cheese?!

  3. melissa @ the delicate place permalink
    April 23, 2010 12:15 am

    mae! i love cheese, i made perfect mozz & ricotta. see my post about it here. it did take a little bit of my time but it was so worth it! who doesn’t love a good caprese? http://thedelicateplace.wordpress.com/2010/02/15/diy-mozzerella-ricotta-from-raw-milk/

  4. April 23, 2010 7:51 am

    I’m so impressed that you make cheese in your high school lab! We didn’t even do that in my college food science class! (Instead, we did things like cook meat in a microwave – informative, but not so interesting).

    Have a WONDERFUL time on your trip, Mae! 🙂

  5. April 23, 2010 12:30 pm

    LOL i love that you labeled your mom as “ohh mom” thats cute!

  6. April 24, 2010 7:11 am

    I am thoroughly impressed that you made your own cheese. I LOVE cheese but I think I’ll leave the science to you and the cheese makers 🙂 I am soooo bad with science and chem. I’ll just buy my cheese. I enjoyed reading yesterday’s article though. It’s crazy how much stuff we can get from milk too: cheese, yogurt, protein powders, etc…

  7. April 24, 2010 8:03 am

    That is some impressive cheese making! Geez. And I was proud when I made “cheesecake” by straining the liquid via putting the yogurt in a coffee filter, suspending it in a cup, and letting it sit for a day in the fridge…
    Anywho, I was wondering… I just started a blog myself (!!) and all my pictures are getting cut off! How do you get them to be the perfect size?

  8. April 25, 2010 6:23 am

    Whoa, I’m definately doing that for my extra credit AP demo!! 😀

  9. Katherine: What About Summer? permalink
    April 26, 2010 6:33 am

    mom is brutally honest in that pic!

  10. April 27, 2010 6:17 am

    You are amazing! I can’t believe you made your own cheese! I love your curiosity and fearlessness in the kitchen!

  11. April 27, 2010 9:02 am

    hehe coagulation.. what a word eh?

    and ur mom gives it a thumbs down… 😦 o well…

    jealous of u gonig to florida and bloggin!!! girl im turning green with envy!!!

    xoxo ❤

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