Monday, February 13, 2012

Cheese- my favorite!

Cheese: a major nutritional staple in human life.  But when did we discover this delicious substance?  How did we discover it?  And what's really going on in the transformation from milk to cheese?  If your interest in our many-flavored friend matches my own, read on to have these questions (and others!) answered.

People started enjoying cheese when they started domesticating mammals, around 9000 B.C.E.   Records of humans and cheese date from ancient Greece to biblical times to the Middle Ages and up to current time.  Cheese-making is referenced in many famous literary works throughout history.  For instance, the creature Cyclops from The Odyssey is well known for his gargantuan size and singular, looming eye but the description of his sophisticated cheese-making operation often goes unnoticed.  Later on, The Bible notes that David was simply delivering cheese when he ran into the giant Goliath in the beginning of David and Goliath.  These stories and other ancient relics suggest that humans and cheese go way back, but how did we first meet?

It's unknown how cheese was first discovered but there are many legends.  All of these legends refer to humans that got very familiar with certain animal's stomachs before they tasted cheese.  When an animal was killed in the olden times, every piece of it was used for something, including the stomach.  People realized that the stomach made a pretty good sac, or ancient backpack of sorts, for traveling people.  Not exactly L.L. Bean status but a pretty good early model.  Eventually someone tried to carry milk in this sac, probably in the hot, midday sun, and that was all nature needed to introduce humans to a new kind of dairy.  When the traveler opened the stomach sac, he or she found that the original liquid milk was replaced by a watery substance with bundles of thick, rich clumps.  Thank goodness the ancient traveler was too hungry to be picky and tried these clumps, discovering cheese!
Property of Steel Wool from Flickr

Because cheese was most likely discovered by carrying milk in a stomach sac, original cheese-makers followed this method: kill a young cow/goat/sheep, remove its stomach, store milk in it for some amount of time, and cut it open to find cheese.  Later on, simpler ways were discovered to get the same outcome.  These advances in cheese-making stem from an understanding of the process of changing milk into cheese.

Milk is the starting material for cheese-making, which is also referred to as 'saving milk'.  Milk is mostly water with a variety of proteins, minerals, sugar (lactose), fat (butterfat), vitamins and other elements that make up milk solids.  Cheese is produced by curdling milk, AKA forcing milk proteins (called casein) to change shape and entrap the other parts of the milk solid to form curds.  Whey is the watery portion left behind when curds form.

There are two main strategies used to force milk to curdle, and for maximum efficiency these strategies are usually used in tandem.  The first strategy involves decreasing the pH (acidification) of the milk.  Acidification is the result of bacteria that naturally occur in the milk, or the addition of a bacterial starter to pasteurized milk.  These bacteria use the sugar lactose as a source of food and in doing so produce lactic acid as a waste product, which acidifies the milk.  This will eventually lead to curdling but it is a slow process and can make for crumbly, sour cheese.

To ensure curdling when milk is still sweet (not acidic!) a second strategy is used called rennet.  Rennet is a group of enzymes, mainly chymosin, that act to change the shape of milk proteins and cause curdling.  Heat and movement increase the action of the enzymes in rennet and make for faster curd production, which is why the story above suggests the traveler was walking in the hot sunshine.  Rennet is naturally found in the fourth stomach of young goats, cows, sheep etc. to help them digest their mother's milk.  Interestingly, rennet is also found in a variety of plants, including the bark of fig trees, stinging nettles and butterwort.  Some stories claim that cows were fed with butterwort before they were to be milked so that the collected milk would turn to cheese some hours later.  (An aside, modern cheese production uses the same enzymes but they're produced by genetically engineered bacteria so we don't always need a stomach on hand.)

Once the milk is curdled, the curds can be prepared and eaten right away (as ricotta is) or aged with certain spices, bacteria or fungi to produce different types of cheese (such as cheddar or blue cheese).  Flavor and texture depend on the composition of the milk used, and how long the cheese was aged.  This dynamic process has a world of opportunity and can make for some truly tasty treats!

We have an approximate 1,112 year history with cheese and I'm happy to report that this lengthy love affair has no end in sight.


  1. Thank you for reminding me of my favorite cheese-related thing (short of cheese itself):

  2. Hannah, you covered this topic before I could get around to it! I am so fond of cheese.

  3. And, of course, don't forget the greatest cheese of them all, Humboldt Fog ( Only requires a short trip to Wegman's in Erie...

  4. Glad to see there are other cheese-lovers out there!