Flavor and Species: Delving into Milk Chemistry!!

On the surface, there are few things more boring than a plain old glass of milk. But of course, being cheese people, we see nothing but a world of potential there. While what milk eventually becomes is the object of our affection, milk in its liquid state tells a story all its own and reveals how our favorite cheeses get to be themselves and develop their own unique character.

In order to understand how differences in milk equate to differences in cheeses, outlining how the milks of different species are unique from one another provides a great  jumping off point.

Milk is, essentially, a whole bunch of solid nutrients packaged into a convenient delivery system: water. Liquid milk is about 90% water by weight, which enables it to be ingested easily by a newborn animal and also provides them with the hydration that they need. The other 10% is where the nutrition lives, and as cheese folks this is the part that we’re most concerned with. That 10% consists of proteins, fats, minerals and sugars, all of which have their own unique role to play when milk gets turned into cheese.

Arguably the most important component at play here is the protein. Protein is what makes up the physical structure of the cheese and, when it is broken down by enzymes during aging, contributes the most distinctive flavors to the cheese. The main protein in milk, known as casein, exists as tight bundles of smaller protein particles (called micelles) held together with calcium. These micelles can be pictured as a sort of koosh-ball shape: a single particle surrounded by tons of tiny filaments. All of these projections on the outside are known as kappa caseins, and carry a negative charge, which causes them to repel one another when they collide. This is what enables the solids in milk to be suspended evenly throughout the liquid component, giving milk its opaque appearance. When a cheesemaker makes cheese, they are essentially working to undo this negative charge on the micelles in order to cause the proteins to stick together, forming a curd and pushing out water (aka whey) in the process.

In addition to the proteins, milk contains an abundance of fat, which is of the utmost importance to the cheesemaking process. The fats in milk are referred to as butterfats, which consist of a specific type of fat called triglycerides. These molecules, called globules, are made up of several smaller fatty acids (basically just chains of carbon atoms) stuck together and (continuing with the toy comparisons) are shaped like tiny beach balls, with a thin negatively charged membrane surrounding the outside. When curd is formed, the globules are swept up into the coagulating proteins and trapped within the curd structure, trapped in a sort of protein net.

The rest of the solids in milk consist of minerals (most of which is the calcium holding those protein micelles together) and lactose, the sugar component of the milk. Lactose provides much needed energy that the newborn animal will use to grow rapidly, but in the cheesemaking process lactose is important mostly in that it is turned into lactic acid by starter culture bacteria, which prepares the milk to be curdled.

So, with the basics in mind, how does cow’s milk differ from goat’s milk, and how do these differ from sheep’s milk?

Since humans settled down and started farming, cows have been selectively bred to be the most efficient and productive milk machines that they can be. Cows are able to produce up to 5 gallons of milk per day, and are able to be milked about 300 days out of the year.

The milk that they produce is very balanced, with solids making up about 12.7% of the overall volume of their milk, and with fat and protein taking up 3.7% and 3.4%, respectively. The consistency of their milk, combined with the sheer volume that they can produce throughout the year, makes cows the animal of choice for most cheesemakers looking to produce cheese on a larger scale year-round.

Sheep, on the other hand, represent the opposite extreme. Their milk is far and away the the richest in solids, with proteins, fats and other solids making up 19.3% of the overall volume of the milk (with a whopping 7.4% being pure fat). This translates to a much higher cheese yield from the milk, meaning that, say, 10 gallons of sheep’s milk will make more cheese than 10 gallons of cow’s milk.

While this might make the humble sheep sound like quite the efficient cheese machine, a ewe will produce far less milk per milking that a cow or a goat. In fact, over their entire lactation cycle (meaning the amount of days per year that the animal is producing milk), a sheep will only give about 12% of the milk that a cow would over the same amount of time. This, combined with the fact that, like goats, sheep are seasonal breeders and can only be milked for about 180 days per year, means that a sheep produces a comparatively tiny amount of milk. And while the milk that they do produce makes quite a bit of cheese, a farmer raising sheep will still end up with only a fraction of the cheese yield at the end of the day than they would if they were milking cows.

Right in the middle of the road we find our friends the goats. Goats’ milk is very similar in composition to cow’s milk, with 12.4% overall solids and comparable amounts of fats and proteins. However, like sheep, goats are also finicky seasonal breeders and only produce milk for about 8 months out of the year. During those 8 months, goats produce quite a bit more milk than sheep do per milking, meaning the overall volume of milk produced during their lactation cycle will be more than a sheep but less than a cow.

With all of these differences in mind, there is of course the questions of just why cheese made from each species milk taste different from one another. While the base ingredients are all the same (protein, fat, minerals), the makeup of each of these components varies greatly between types of animals. For instance, sheep’s milk contains fat globules that are massive compared to the size of the fats in goats milk. When cheese is made from sheep’s milk, this will lead to the fats dominating the flavor more, giving a stronger herbal, earthy and peppery flavor once these break down during aging.

Similarly, the chemical makeup of these elements (not just the size) can determine differences in flavor as well. Goat’s milk, for example, contains a higher proportion of a particular type of fatty acid in its fat globules that is quite volatile and breaks down very quickly and easily during aging. This leads to the distinctively “goaty” aroma that is so familiar in an aged goat cheese, and explains why that particular flavor can’t be found elsewhere.
Finally, even within species, the milk composition (and therefore the flavor of the cheese) can differ greatly between breeds. Holstein cows (the ubiquitous black and white cows that dot the highways of the USA) produce a relatively mild milk due to the balanced nature of the nutrients, while Jersey cows (a breed developed in the British Isles for buttermaking) produce a milk much higher in butterfat, making for a more aggressively and distinctively flavored cheese.

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The Silver Fox Extra Fancy Baller Toasted Specatacu-Cheese-O-Rama!

8BA83BFC-7CC2-43EE-A498-A303FEA3FF25In honor of Grilled Cheese Month, we’re celebrating all things melty by teaming up with our favorite NYC restaurants to get their take on the best way to enjoy the ultimate comfort food!

This week, cheese lover John Winterman of Michelin-Starred restaurant Batard puts Cabot Clothbound Cheddar at center stage for a luscious sandwich that is equal parts grilled cheese and Welsh rarebit. Cabot’s brothy and savory character is highlighted by cooked leeks, while the subtle fruit flavors are accented with a touch of nutmeg.

John Winterman’s Grilled Cheese

– 3 tablespoons butter
– 1/4 cup flour
– 2 cups milk
– 1/2 pound Cabot Cheddar (cubed)
– black pepper to taste
– pinch fresh grated nutmeg
– 1/4 cup melted leeks
– pickled red onion

Melt butter in pan, add flour and whisk to combine. When blended add milk, slowly, but whisk rapidly as milk is combined and thickened. Add cheese slowly, over low heat, until melted – do NOT cook further.

Fold in black pepper and nutmeg. Fold in melted leeks.

Ooze mixture onto two slices of toasted bread and place in oven which you cranked to 400 degrees F. When bubbling, remove from oven, top with pickled red onion, and close the sandwich

Baller move: mix in a little Newcastle Brown Ale into the sauce.

 

Crafting the Perfect Grilled Cheese… With Science!!

Right on the cusp of spring but still chilly, gray and rainy, it’s no wonder that April has the unique honor of being designated National Grilled Cheese Month!

While we of course celebrate year round, we thought that the occasion presented a perfect excuse to address one of the most common questions a cheesemonger gets: what’s the best cheese for a grilled cheese sandwich?

As with anything else, asking someone obsessed with something a question about that very thing will provoke a response way, way longer and more involved than the asker bargained for (or even wanted). Never ones to disappoint, we’ve decided to take a deep dive into what exactly it is that makes a cheese worthy of being melted between bread!!

What it all comes down to in the end is the chemical makeup of the cheese and how different cheesemaking techniques result in very different behavior in the final product. We thought the most useful way to go about explaining this would be to point out the differences between how a few common melting cheeses (cheddar, Swiss-style and mozzarella) are made and how their production process affects how they melt. Get ready for some serious curd-nerding!!

While cheddar is often thought of as the go-to cheese for most melting applications, its reputation is, in truth, somewhat unearned. Since the term “cheddar” is not in any way protected in the USA, just about any product that vaguely conforms to customer’s expectations of a typical “cheddar” flavor, texture and appearance can label itself as cheddar cheese. In absence of any regulation, a typical supermarket will stock a dizzying array of products all sporting the name “cheddar”, even though sometimes not a even single one of them is made according to the traditional process.

Having been produced differently, these cheeses are chemically different and, as a result, will behave differently in the presence of heat.

One of the things that separates a true cheddar from the herd is, apart from its make process, the pH levels at various stages in its life cycle and the effect this has on the cheese’s physical makeup. Cheese is made up of milk protein, aka casein, molecules that have stuck themselves together (forming curds) and pushed out moisture (whey), trapping fat and minerals in the process. These casein molecules are made up of small protein particles held together by calcium phosphate, which acts as a sort of glue. This “glue” dissolves in the presence of acid, weakening the structure of the casein and, as a result, the structure of the cheese overall.

When traditional cheddar cheese is made, the milk is left to a reach a medium-low pH before the curds are formed, creating a higher-acid environment that eats away at the calcium glue holding the protein structures together. Additional acid is produced in the cheese during aging and storage, and by the time it’s ready to eat a well-aged cheddar will have lost much of its resilience. Since the structure of the cheese has been weakened, it will tend to collapse when heat is applied, separating from the fats and resulting in a gritty, oily texture. (Side note: this is true when talking about traditional, English-style aged cheddars. If you’re looking for melty cheddar goodness, a younger, higher-moisture cheddar will serve your needs perfectly!!)

By contrast, alpine-style cheeses such as Emmental or Gruyere (or domestic favorites like Alpha Tolman and Reading Raclette), which have a lower-acid environment during their make process, will melt more smoothly and evenly. The higher pH ensures that less calcium is dissolved, making for stronger protein bonds, which in turn protects the structure of the cheese and keep other solids like fats and minerals trapped snugly within the curds even when heat is applied. This leads to the coveted silky, ropey texture we’ve come to look for in dishes like raclette and fondue.  

Apart from the chemical processes at play, the physical handling of curds in alpine cheeses also contribute to their superior meltability. Whereas in cheddar making the curds are separated from their whey, pressed into blocks which are then stacked onto each other, then run through a mill to break them up, curds destined to become Comte or Appenzeller receive a more delicate treatment. The curds are left in the vat with their whey, where they are gently cooked and cut down into pieces no bigger than a grain of rice. Then, either by hand in the vat or via mechanical pump, the curds are pressed together and formed without ever having the whey drained off in a process referred to as “pressing under the whey”. This enables the curds to knit together without ever being exposed to air, eliminating cracks, fissures and pockets in the cheese. The result is an extremely smooth, “closed” texture and a low “friability” (aka ability to be crumbled) factor in the final cheese, which helps it hold together tightly during melting.

On the other end of the spectrum, there is of course what may very well be the world’s most famous melter: mozzarella. And though it’s notoriety comes most often from its role atop pizzas, to dismiss it as a grilled cheese ingredient would be a big mistake.

Mozzarella is part of a family of cheeses known as “stretched curd” or pasta filata. This style of cheese is named for the fact that the curd, immediately after forming, is cut and then kneaded by hand like dough. The cheesemaker repeatedly stretches the freshly formed cheese, folding it over onto itself before each pull. Much like layers in croissant dough or puff pastry, this process creates thin layers of protein, which are stacked on one another over and over again throughout the kneading, reinforcing one another. The result is the familiar bouncy, stretchy and snappy texture that makes melted mozzarella so universally beloved.

So, with all this in mind, our original question still stands: what type of cheese makes for the best grilled cheese?!

Given that each type brings something different to the table, our professional opinion as cheesemongers and disciples of hot cheese is that the best route to go is a blend. We recommend playing with proportions to meet your individual tastes and needs, but a typical winning combination should go something like this: a good cheddar for acidity and salt, an alpine style for sweetness and body, and a fresh or pasta filata cheese as a binding agent.

As always, the preference of the person doing the grilling is the most important factor in crafting the perfect grilled cheese. But, armed with a little science, we hope you’ll experiment often and freely!