First Person

Adventures in Cheesemaking

One engineer's mishaps and misadventures on the road to mozzarella


It was Friday, one o’clock in the morning, four hours into my supposedly two-hour homemade mozzarella recipe, and I found myself standing before a pile of cheese more akin to a ball of warm cauliflower than an artisanal dairy product. The “cheese” crumbled between my fingers like wet sand, and when I cautiously sampled a pinch of my work all that came to mind was damp, salty cardboard.

My desire to make cheese arose from my desire to eat cheese. I have an old habit of researching foods I tend to eat, and that research often results in an attempt to recreate my favorite dishes at home. As a student of the sciences, I set out on my cheesemaking ordeal under the impression that if I could solve differential equations, analyze blood flow models, and pass a course titled “Chronobioengineering,” I would have no problem separating curds from whey to make a little cheese.

I dove headfirst into a mozzarella recipe by Aki Kamozawa and H. Alexander Talbot from their excellent book Ideas in Food (they author a blog of the same name). The relatively simple recipe calls for only five ingredients: milk, citric acid, rennet, and salt. Rennet, a key ingredient, is a mixture of enzymes produced in the stomachs of mammals that assists with digesting milk, and, when used in cheesemaking, helps with the coagulation of cheese curds. This enzyme mixture is commercially extracted from the stomachs of calves slaughtered for veal, and sold in tablet and liquid form.

I immediately began running into problems as I couldn’t find citric acid or rennet. I also had trouble finding high quality milk. The recipe notes that while raw milk is ideal, low temperature pasteurized milk is suitable as well. Many supermarket dairy products are pasteurized at high temperatures; ultra-high temperature pasteurization, for example, brings the milk above 275 degrees Fahrenheit for just a few seconds. The high temperature kills any harmful organic life in the milk, but denatures many of the proteins essential to cheesemaking.

I purchased Junket brand rennet tablets, advertised mostly for use in custards and ice creams, online, and found someone on the internet who claimed that a third of a cup of lemon juice contained about a teaspoon on citric acid, so I bought a few lemons. Following the recipe as closely as possible, I found myself face-to-face with an inedible mass of mystery cheese in just under two hours. Besides the slightly acidic odor of spoiling milk, one would have been hard pressed to identify my creation as cheese. Every surface of my kitchen was splattered with drying milk, and smoke billowed up from the site of one of the larger spills on the range top.

The culprit was most likely a combination of miscalculated substitutions, impatience, and my total lack of experience. Only mildly deterred, I pushed the cheese lump to the side without even tasting it, and decided that finding higher quality, less processed milk and real citric acid would help ensure that batch two would be sliced and resting on a bed of tomatoes and basil by dinnertime the next day.

Citric acid was the easiest problem to solve. I was able to find some at a local homebrew supply store for a few bucks. I decided that I would have to make do with the rennet tablets. Junket rennet tablets only have a small amount of the desired enzymes, but finding liquid rennet is not always easy.

Finding milk that hadn’t been pasteurized at high temperatures proved to be more difficult. Milk producers do not often explicitly define their pasteurization methods. Ultra-high temperature treated (UHT) milk is easy to spot because it does not require refrigeration, but some supermarket milk is pasteurized to higher than necessary temperatures to avoid contamination (and lawsuits). I managed to find some milk which claimed to be low-temperature pasteurized to use for my second attempt.

With my new, nearly perfect ingredients assembled, I fired up my electric stove and began heating up a gallon of the most expensive milk I’d ever purchased. At 50 degrees, I stirred in the citric acid. At 80 degrees, I stirred in half of a dissolved rennet tablet and cut the heat. Everything was going according to plan. I set my timer for 30 minutes, covered the pot, and paced nervously around my kitchen until the timer was close enough to zero that I stopped it early and excitedly removed the pot’s lid.

The key moment in cheesemaking seems to be the elusive “clean break.” This is the stage when the milk has curdled in a uniform silky mass, and you are supposed to be able to gently pull the curds away from side of the pot with the back of your hand with no residue left behind. I never reached this stage with my first batch, and after cautiously poking my second attempt I was worried that I’d never get it right. After another hour of cutting, heating, stirring, and kneading, I was left with a spitting image of my first batch. The similarities were uncanny ā€” at least I could be proud of my consistency. I decided I would need some professional help if I wanted to move myself out of cheesemaking limbo.

I found my answer at the Valley Shepherd Creamery in Philadelphia’s Reading Terminal Market: prepared curds. Cheesemaker Jamie Png creates fresh mozzarella on a daily basis from them. This curd, which is essentially unprocessed cheese, allows Jamie to prepare consistent batches of mozzarella in under an hour. The curd can be refrigerated, even frozen, whereas the mozzarella must be consumed soon after the preparation for the ideal texture and flavor. After refrigeration, mozzarella toughens, becomes chewy, and loses some of its natural, delicate sweetness.

Starting from curd, however, does not remove the need for a skilled hand in the cheesemaking process. Jamie works instinctively, adding hot and cold water to the curds while gently agitating the mixture with a large paddle. Once the curds come together, she sets the paddle aside and finishes the process by hand, allowing gravity to gently stretch each portion of cheese before deftly braiding the cords into their final forms. After resting briefly in cool brine to receive a uniform, mild saltiness as to not overpower the natural flavors, the cheese heads to the front counter for sale. Before heading back home, I bought a couple pounds of curd from the Valley Shepherd.

With the tools I needed in hand, I began my final attempt at crafting mozzarella. I sliced the curds, combined them with water heated to 180 degrees, and started to gently knead them as they melted. The curds formed a smooth mass, and I was able to stretch the cheese into a rope reminiscent of those I had seen earlier. In lieu of an elaborate braid, I made two quick knots and prodded the cheese into a shape I was comfortable presenting.

I was stunned at how appetizing my creation looked, especially when I thought back on my initial failures. I fried some toast and decided to leave the tasting to the professionals at the editors’ desk. After assuring everyone that the cheese probably wouldn’t make them seriously ill, and taking the first slice as a sign of confidence in that fact, the writing staff made quick work half of a pound of cheese.

As pleased as I was with my final results, I’m not about to toss my supermarket-purchased cheese in the trash and start making all the cheese I eat from scratch. My experience was a lesson in scientific humility. Three-quarters of a college degree wasn’t quite enough to earn a position in the centuries-old art of cheesemaking. After going through the process, I have a newfound respect for cheese and cheesemakers, both artisanal and industrial. If you’re looking for a project with potentially delicious results, experiment with home cheesemaking, but if you’re searching for the perfect cheese to compliment a meal or a fine wine, strike up a conversation with your cheesemonger and put your trust in the professionals.


  1. Ann Harden says:

    Kevin, We have a customer who came up with a kit to make mozzarella. It had all the ingredients and a thermometer in the kit. The only thing you had to add was the whole milk. I tried it and had the same failture you had with your first. Unfortunately, I did not try it a second time. Yours looks good enough to eat right off the screen! Great Job. Love, Grandma

  2. Looks delicious! You can find raw milk in Reading Terminal — and fermented cagliata curds from Caputo Bros. (also used in home mozz making) — at the Fair Food Farmstand.

  3. Carol says:

    There’s a great tut on mozz making at Jabez Farms blog. It looks pretty straightforward, but I haven’t made it yet. Hope to soon.

  4. love cheese looks delicious smells delicious taste delicious

  5. Mozzarella is my cheese making nemesis.I am glad it worked out in the end.

  6. Carol says:

    So enjoyed the writeup you did. Especially the humor about yourself and failures. Please forward any future attempts. Love, Grandma ps. You look great & hope the new job is a success for you. Does it involve cheese?

  7. Madame Fromage says:

    Lovely post! I’ve heard the same thing about mozzarella kits. It’s not an easy cheese to make at home. Glad to see you met Jamie Png, Kevin. She makes exquisite mozz.

  8. NeilPuck says:

    My early attempts also resulted in the samer failures. Mine resembled solidified ricotta more than mozzerella. I was amazed how many of the recipes steered me wrong. The secrets: raw whole milk (available at Reading Terminal Market), and liquid bovine rennet (mail order). Throw the junket rennet tablets away, they’re useless. The other key is to skip the second heating step. Once you’ve gotten the clean break, cut up the curds, drain until all of the whey drains out. Then slice up the curds again and then you can continue with the hot water steps outlined in your article to stretch and form the cheese. I’ve made it successfully several times.

  9. Matt G says:

    Tried making mozza for the first time 2 days ago. It seemed to have turned out perfectly. Great elasticity when it came to the stretching stage and nice and smooth and shiny once formed. The next day when I checked it though, t seemed to be “bleeding” milk. When i picked it up it was almost as if an ice cream scoop was melting in my hand. I weighed it and over 24 hrs it lost about 7g. Is this typical for fresh mozza? Is there a step I am messing up? Or would it have something to do with my ingredients? I used unhomogenized whole milk, powdered lipase, citric acid and liquid rennet.


    Oh yeh, it tasted fantastic. Much better than any store bought stuff I’ve had, so hopefully I can get over this hurdle.

  10. Jim says:

    I have been using Junket rennet for some time t make cheese. The secret of use is use 1 tab per gallon of milk. As for the milk if you use no homogonized (sp?) -this can be found at whole food markets chain of stores. It comes out fine. as a starter for regular pasturized milk put 2 oz of yogurt (with live cultures in the milk and stir 5 hours before starting your cheese attempt. leave at room temp. and if a clean break doesn’t happen in a half hour just wait a little longer 1 usually wait about an hour before checking for the break.
    Cheeses I have successfully made with junket
    Mozzarella, american basic, provolone, cheddar, parmessan and romao, feta, gouda and of course ricotta( I love cannoli’s) and also gyetost(sp?) norwegian cheese made form leftover whey

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