Category: Food Science

By Chef Joe LaVilla

Once the “darling” of the 1950s Americana kitchen, pot roast seems to have gone the way of Malt-o-Meal—in a word, “extinct” (or in exile, depending on how you feel about Malt-o-Meal). While it would be nice to think that the death of pot roast is due to a more sophisticated American palate, the more likely culprit is the modern cook’s inability to correctly execute a proper stew or braise. Sorry Rachael Ray fans, you just can’t do it in 30 minutes.

The terms “stew” and “braise” fall under the category of moist-heat cooking methods, meaning they use liquid to transfer the heat to the meat (or vegetable—but that doesn’t rhyme as well). The differences in the methods are the size of the product that is being cooked, and how much liquid is used in the process. Stews are typically made from smaller pieces of meat and vegetables which are completely submerged in cooking liquid, while braises consist of larger chunks of meat or vegetables which are submerged in enough cooking liquid to reach about halfway up the product. For the purposes of this article, I’m going to go ahead and use the term “braise”, because aside from those minor differences, it’s essentially the same method, and because “braise” takes precedence– alphabetically speaking.

The first step toward achieving a good braise is selecting the appropriate raw product. A premium New York Strip may be beautiful on the grill, but it is not good braising material. Instead, reach for a nice pork shoulder or chuck roast. Many people associate these cuts of meat with gristle and fat, but it is these attributes that make for a tender, succulent braise. As for vegetables, more mature items are your best bet. Older vegetables have more lignin (firmer cell walls) than baby or young vegetables do.  The lignin softens when moist heat is applied, and in some cases pectin (sugar) develops, creating a softer, sweeter product. 

So, how, you’re wondering, can that big, fatty hunk of meat possibly be better than that plump, cherry-red New York Strip? It’s actually the fat and connective tissue that gives the meat its flavor, silky, texture, and juiciness. These pieces come from the shoulders, legs, and rear-end of the animal; in other words, the muscles that are used most while the animal is alive. The connective tissue is made of collagen which holds the muscles together, while the marbling (or fat) helps lubricate the muscle fibers.   

During the braising process, the heat from the stove is slowly transferred to the meat through the simmering liquid.  As the meat reaches ~180 degrees, the collagen begins to transform into gelatin, lending an unctuous texture to the meat. This process takes time and requires temperature control since the collagen will not completely convert to gelatin until the temperature reaches at least 210 degrees. You MUST allow this process to occur gradually. It may seem logical to raise the temperature to 210 degrees as quickly as possible, but this will only result in a product that has the flavor profile of cardboard.

 Don’t forget that those muscle fibers in the meat hold a great deal of liquid. The fibers are also made of protein which denatures and changes shape when it is exposed to excessive heat. If the fibers get too hot too quickly, they seize-up and force the highly concentrated liquid within the fibers, as well as the cooking liquid they have absorbed, out of the meat. Heating the meat too quickly also causes the fat in the muscle to melt and run out from between the fibers. The equation is very simple:  Meat-Fat-Moisture=Yuck.   

Making a great braise is not rocket science. It just takes time, patience, flavorful cooking liquid, and a well-executed sear (check out the article on the Maillard reaction). Dredge the meat (or veggies) in flour, salt and pepper, sear it in a hot pan, and add the cooking liquid. When the liquid begins to simmer, most cooks transfer the pot to a hot oven to maintain an even temperature in and around the product. Leave the lid ajar to prevent the liquid from coming to a boil, grab a book or turn on a movie, and let your dish cook, low and slow.

Do I hear you all pulling out your Dutch ovens? Let’s give pot roast another try.

About Joe LaVilla

Chef LaVilla is the Academic Director for the Culinary Arts programs at the International Culinary School at the Art Institute of Phoenix. Besides being a Certified Executive Chef, Chef LaVilla also holds a certification from the International Sommelier Guild (ISG) as a Certified Sommelier. In addition, Chef LaVilla is experienced in food styling, food and wine pairing, the hospitality industry, culinary arts management, and more.

Before joining The Art Institute of Phoenix, LaVilla had been Executive Chef for Tucchetti restaurant in Phoenix. He has worked for Mark Tarbell as well as Wolfgang Puck. His credits include, “Faculty of the Year” award at The Art Institute of Phoenix; finalist in the Arizona Pork Council Taste of Elegance Competition; and author of the textbook “The Handbook of Wine, Beer and Spirits: A Guide to Styles and Service”.

Chef LaVilla received his Ph.D. in Organic Chemistry from the University of Rochester and his Bachelor of Arts degree, Cum Laude, in Chemistry from Cornell University. He also received an associate’s degree in Culinary Arts from the Culinary Institute of America, where he graduated with honors.

by Chef Joe LaVilla

In the weeks leading up to Valentine’s Day, you probably watched your favorite TV Chefs prepare chocolate-dipped fruit more times than you’d like to admit. Maybe you even invested in the ingredients to try it yourself. It’s easy, right?

 Easy Steps?

1.) Melt chocolate.

2.) Dip fruit.

3.) Place on wax paper and refrigerate.

4.) Consume finished product in an immaculate kitchen.

I hate to break it to you, but you are one of the billions who have fallen victim to television deception.

Entertaining as they might be, these chefs gloss-over the detailed process of producing chocolate that snaps at room temperature, but melts on the tongue. In short, they avoid telling you about chocolate’s temper. I am not suggesting that there is some evil side to chocolate (unless you’re dieting), but it is a relatively “moody” substance that must be melted carefully to avoid a lumpy, runny, or dull result.

So why, you ask, is chocolate so fussy? The answer lies in its chemical structure. Grab your pocket-protectors folks: today, we’re going to learn the science behind a proper tempering technique.

A good, basic dark chocolate bar should contain only 3 ingredients. These are cocoa powder, cocoa butter, and sugar. The bitterness of the chocolate is dependent on the percentage of cocoa present in the bar. Many higher-end chocolate manufacturers will include percentages on their bars indicating the percentage of cocoa bean the bar contains. For example, a 74% bar contains 74% cocoa bean and 26% sugar; likewise, the higher the percentage of cocoa bean, the more bitter the bar will be.

While sugar and cocoa-content impact the flavor of the bar, the cocoa butter controls its appearance. Cocoa butter is the fat in the cocoa bean which forms crystalline structures, giving a chocolate bar its firm texture and smooth, shiny surface. These crystalline structures make for a chocolate that “melts in your mouth—not in your hand.”

Tempering is the word we use in the culinary world for the process of melting and cooling chocolate in a controlled manner. Taking melted chocolate and putting it in the refrigerator will set the cocoa butter into soft-form crystals which will be hard when removed from the fridge, but as they come to room temperature, will be soft, dull and pasty-feeling on the palate. If you’ve ever put a candy bar in the fridge after you left it in the car on a hot day, you’ve experienced this. Nobody likes a heat-stricken Snickers.

If you invest in one tool for your personal chocolatiering, make it a good candy thermometer. You’ll need it to keep track of temperatures as you temper your chocolate.

The first step in the process is to chop the chocolate into small pieces reserving ~1/3 of the chocolate for later use.

Next, you can begin the melting process. This can be done using a double boiler or in a microwave. If you’re using a double boiler, it is important to keep the water at a very low boil to prevent any droplets of water from getting into the melting chocolate. Water will cause the chocolate to “seize”, becoming a clump of grainy, stiff putty that will not melt. Take care in using the microwave as well.  Only microwave the chocolate for about 10 seconds at a time as it is easy to burn and there is no way to revive it. The optimal melting temperature for chocolate is between 110 and 115 degrees Fahrenheit so keep that thermometer handy!

Once you have melted the chocolate, stir it until there are no lumps, then set it aside so that it can continue melting the remaining sugar and fat crystals.

After letting it rest for ~ 10 minutes, it’s time to add the reserved chocolate shavings little by little to the melted chocolate, stirring until they melt. The shavings are providing building blocks or “seed crystals” for the melted cocoa butter to align with. This “seeding” helps the cocoa butter form the proper crystal structure while gently reducing the temperature of the mix. Continue adding the shavings until the temperature of the mixture is 86 degrees. 

At this point, you must reheat the entire mixture to 89 degrees.  Do NOT exceed 90 degrees or you will ruin the batch.

Testing whether you have properly tempered the chocolate is easy. Simply drizzle some on a piece of parchment paper or dip a paring knife into the mixture. After ~5 minutes at room temperature, the chocolate should be firm, shiny, and ready to enjoy.

Bon Appétit!

To see additional Food Science features click here: FOOD SCIENCE

About Joe LaVilla

Chef LaVilla is the Academic Director for the Culinary Arts programs at the International Culinary School at the Art Institute of Phoenix. Besides being a Certified Executive Chef, Chef LaVilla also holds a certification from the International Sommelier Guild (ISG) as a Certified Sommelier. In addition, Chef LaVilla is experienced in food styling, food and wine pairing, the hospitality industry, culinary arts management, and more.

Before joining The Art Institute of Phoenix, LaVilla had been Executive Chef for Tucchetti restaurant in Phoenix. He has worked for Mark Tarbell as well as Wolfgang Puck. His credits include, “Faculty of the Year” award at The Art Institute of Phoenix; finalist in the Arizona Pork Council Taste of Elegance Competition; and author of the textbook “The Handbook of Wine, Beer and Spirits: A Guide to Styles and Service”.

Chef LaVilla received his Ph.D. in Organic Chemistry from the University of Rochester and his Bachelor of Arts degree, Cum Laude, in Chemistry from Cornell University. He also received an associate’s degree in Culinary Arts from the Culinary Institute of America, where he graduated with honors.

By Chef Joe LaVilla

If there is one holiday menu item that strikes fear in the hearts of cooks, it is the gravy. For some, it is the stuff of legendary failure; for others, it is a long- standing family legacy that has saved even the driest turkey. Whichever camp your gravy falls into, understanding the science behind the technique to making this simple sauce will ensure that the best gravy never fails, and the worst stays out of the garbage disposal.

For those of you who believe that gravy is something that comes out of a packet or jar, let’s begin with the definition: Gravy is a sauce made from the pan drippings of a roast, thickened with a roux and enriched with stock.  Of these three ingredients, the roux is often the culprit of many gravy-pitfalls.  Roux is a mixture of flour and butter that is cooked together, and serves as a thickening agent for hot liquids.  Cooking the flour and butter (or any other fat) before adding them to a sauce serves two important purposes. 

The first purpose is to evenly coat the particles of flour with fat.  If the flour is not coated evenly, adding it to the liquid components of your sauce will yield a lumpy texture.  This process is called gelatinization. When liquid comes in contact with a starch granule, it begins to absorb the water and expand.  If a large cluster of granules comes in contact with liquid, only the outside granules will participate in absorption, while the inside granules remain insulated in the center of the cluster. This cluster becomes a non-giblet lump in your gravy. If you had enough time on your hands, a tiny knife, and a magnifying glass, you would see that if this lump were sliced in half, the very interior would still contain dry flour.  By making sure all flour particles are coated in fat, you have more time to whisk them into the liquid before they gelatinize.  This allows you to disperse them evenly throughout the sauce and achieve that silky texture you want.

The second purpose of the cooking process is to cook the protein that exists in the flour and toast the starch. These reactions prevent the underlying “floury” taste of some gravy. Let’s take a look at the structure of these starches and the effect they will have on your gravy:

 Amylose and amylopectin are the two main starches found in thickening agents.  Amylose is a long chain of sugar molecules connected together.  Amylopectin, on the other hand, is a branched-chain starch.  That means it looks like badly made balloon animal, with parts sticking out from the main chain.  The type of starch present in any thickening agent depends on the plant from which it is derived.  Amylose is typically found in grains like wheat, corn, and rice, while amylopectin exists more often in roots, like tapioca and potato.

The properties of amylose and amylopectin make them react differently when they have gelatinized.  Amylose tends to be able to absorb more liquid, which allows you to use less of amylase-based agents.  It also tends to gelatinize at higher temperatures, which means heat must be used to thicken sauces using this ingredient.  On the negative side, amylase is prone to “retrogradation”.  Retrogradation is the process by which the gel binds to itself upon cooling.  A great example of retrogradation is the texture of rice from Chinese take-out.  Fresh, hot rice is soft and fluffy.  Cold rice is hard and dry–seeming under-cooked.  When you reheat the rice, the gelled starch breaks the bonds to other starch molecules, and the fluffiness returns.  If a sauce thickened with amylose is frozen, it breaks down because ice crystals form more easily.  Another unfortunate process that occurs with amylose starches is synerisis.  Synerisis is the loss of liquid as the hydrated starch sits for a period of time.  This is the liquid seen when lemon meringue pie filling is thickened with flour and sits a couple days—you know—that “tide pool” on top?

Amylopectin gels at a lower temperature.  This allows quick thickening without having to heat the liquid excessively.  It also holds up better to freezing and does not experience synerisis or retrogradation.  Regrettably, for those of you penny-pinchers, the starches that are mostly amylopectin tend to carry a heftier price tag.

Now that you’re well-versed in starches and chemical reactions, let’s talk turkey-gravy! Properly made gravy starts with removing the pan drippings and pouring off most of the fat (don’t you dare throw those drippings away though!).  What little fat remains can now be used as the base for a roux, just by adding a little flour and cooking the mixture.  The stock can now be added, and the basic gravy should be lump-free.  Now you can add some of those drippings back because they have concentrated flavor and salt.  To keep the gravy from being too salty, the drippings should be used as seasoning. In other words add drippings/ taste/repeat. 

Don’t panic if the result is too thin, but step away from the flour container! Adding more flour now will give you pasty tasting gravy. Take a deep breath and reach for the cornstarch to make a slurry (a mixture of cornstarch and COLD stock or water). Adding this little paste to simmering gravy will allow you to adjust the consistency to be the rich, thick gravy that you desire.

And there you have it—holiday disaster diverted! No more suffering though bad, lumpy gravy.  Create a new family tradition of great, silky gravy that compliments your hard work on the turkey.  Now, that canned cranberry sauce is another story…..

To see additional Food Science features click here: FOOD SCIENCE

About Joe LaVilla

Chef LaVilla is the Academic Director for the Culinary Arts programs at the International Culinary School at the Art Institute of Phoenix. Besides being a Certified Executive Chef, Chef LaVilla also holds a certification from the International Sommelier Guild (ISG) as a Certified Sommelier. In addition, Chef LaVilla is experienced in food styling, food and wine pairing, the hospitality industry, culinary arts management, and more.

Before joining The Art Institute of Phoenix, LaVilla had been Executive Chef for Tucchetti restaurant in Phoenix. He has worked for Mark Tarbell as well as Wolfgang Puck. His credits include, “Faculty of the Year” award at The Art Institute of Phoenix; finalist in the Arizona Pork Council Taste of Elegance Competition; and author of the textbook “The Handbook of Wine, Beer and Spirits: A Guide to Styles and Service”.

Chef LaVilla received his Ph.D. in Organic Chemistry from the University of Rochester and his Bachelor of Arts degree, Cum Laude, in Chemistry from Cornell University. He also received an associate’s degree in Culinary Arts from the Culinary Institute of America, where he graduated with honors.

By Chef Joe LaVilla

One of my favorite childhood memories of summer is a Lemon Italian ice. It was syrupy, sweet, tangy and refreshing all at the same time. As I grew up and relocated, I found that it was difficult to find that particular treat. So, putting my knowledge of chemistry and the culinary arts to good use, I found that all it took to emulate my it was the perfect proportion of three common ingredients: sugar, fruit, and water. Oh… and a freezer comes in handy too.

If you’re not a fan of Lemon Italian Ice but find sorbets, Granitas, or fruit bars irresistible, you can apply the same chemistry and ingredients to create these confections.  While these icy treats differ in form and texture, you will find that they are basically the same. The distinguishing characteristics are mainly dictated by the proportions of the ingredients used in their creation and the containers in which they are stored.

The basic science behind making an ice treat is the concept of freezing point. The freezing point of a liquid is the temperature at which the free-flowing molecules begin to organize and form a solid.  While it is not possible to make a liquid freeze at a temperature higher than 32 °F (the standard freezing point of water), it is possible to make it freeze at a lower temperature.

One way to drop the freezing point of water is to dissolve something into it.  This is the theory behind salting the roads in winter. The salt reduces the freezing point of the water (precipitation) turning what would be slippery, icy streets into significantly less-hazardous, wet asphalt. The addition of sugar does the same thing in the preparation of an ice-based dessert. Sugar molecules disrupt the organized structure of the ice crystals effectively lowering the point at which the liquid becomes solid.

Why would you want the freezing point of a sugar-water solution to be low? So that it will stay soft in the freezer. It’s certainly easier to scoop sorbet than an ice cube!

Now that the physics of the matter are out of the way, let’s focus on making some ice-treats. 

First you must decide what kind of dessert you’re craving. Do you want a rich, fruity dessert? Something that resembles scoopable fruit juice? Or, a crunchier fruit-ice? Any of these are possible depending on the liquid, fruit, and sugar ratio you use.

The classic recipe for sorbet combines water, sugar and fruit juice. To determine if the correct amount of sugar has been added, a chef will often float an egg in the solution. If a dime sized portion of the egg floats above the liquid, he has added enough sugar. This is the poor man’s hydrometer, a tool for measuring specific gravity or density. A sorbet made with this method tends to have a good texture, but often lacks a vibrant, fruity flavor.

This is where science helps kick the recipe up a notch; that is, enhance the flavor and “scoopability” of the sorbet using more exact measurements and ratios. For a sorbet to attain the correct texture, it has to have a specific concentration of sugar. That concentration needs to be 15-30% sugar. If the solution is closer to 20-25%, the sorbet will be smooth and manageable upon production, but will need to be tempered if it is left in the freezer.  If the mix is between 30 and 35% sugar, the treat is spoon-ready right out of the freezer. Anything that has a higher concentration of sugar will weep syrup in the freezer and in the bowl.

If you’re looking for a dessert with more “bite”, a Granita may satisfy your palate. It is an Italian-style ice with large, dry, flavorful crystals that is made from a mixture of water and/or juice that has a 15% concentration of sugar. The lower sugar concentration means that the sugar has less of an impact on the formation of ice crystals. During the freezing process, the water and juice are allowed to form larger, sturdier crystals that yield more of a “crunch” when devoured.  The mix is frequently stirred to keep it loose and servable.

So, what’s the guideline? 

Well, for two cups of liquid or liquid and puree, add between 5 to 8 tablespoons of sugar. The variation is determined by the sweetness of the fruit. For a very sweet fruit like a peach, 5-6 tablespoons should do the trick, but a lemon would require about 8 tablespoons. If you are using a fruit puree, it is possible to reduce the amount of sugar because the pectin and solids of the puree will help keep the sorbet soft.  

Also, it is important to note the importance of balancing the sugar with acidity. Typically very ripe fruit is low in acidity and high in sugar. For every two cups of a low-acid fruit puree/juice, it is necessary to add a tablespoon of lemon juice. For high-acid fruits, it may not be necessary to add anything. As for my summer memory, Italian ice is about 35% sugar. That concentration explains the slightly syrupy flavor and consistency.

Mimicking a sorbet from the grocery store would involve taking a cup of fruit puree, adding a bit of sugar and lemon, diluting the mixture to yield 2 cups, and freezing. If you only had juice (or coffee, tea, cocoa), taking a cup of liquid, adding about 11 or 12 tablespoons of sugar and a couple of tablespoons of lemon would result in an ice with a more delicate flavor and texture. 

So if the Ice Cream man doesn’t come around anymore, your favorite childhood treat is only as far away as some fruit, sugar and a freezer.

Read more Food Science secrets here

About Joe LaVilla

Chef LaVilla is the Academic Director for the Culinary Arts programs at the International Culinary School at the Art Institute of Phoenix. Besides being a Certified Executive Chef, Chef LaVilla also holds a certification from the International Sommelier Guild (ISG) as a Certified Sommelier. In addition, Chef LaVilla is experienced in food styling, food and wine pairing, the hospitality industry, culinary arts management, and more.

Before joining The Art Institute of Phoenix, LaVilla had been Executive Chef for Tucchetti restaurant in Phoenix. He has worked for Mark Tarbell as well as Wolfgang Puck. His credits include, “Faculty of the Year” award at The Art Institute of Phoenix; finalist in the Arizona Pork Council Taste of Elegance Competition; and author of the textbook “The Handbook of Wine, Beer and Spirits: A Guide to Styles and Service”.

Chef LaVilla received his Ph.D. in Organic Chemistry from the University of Rochester and his Bachelor of Arts degree, Cum Laude, in Chemistry from Cornell University. He also received an associate’s degree in Culinary Arts from the Culinary Institute of America, where he graduated with honors.

by Chef Joe LaVilla

What is it about the primal urge we have to place meat over fire? The sound of sizzling meat, the allure of smoke, and the beautiful grill marks are all enticing. The real draw is the result of high heat mixing with glycogen and protein in the meat; thus, creating a delicious new taste through the application of science.

When a piece of meat is placed over high heat, several things happen.  First, the proteins begin to denature and then coagulate. If looked at under a very powerful microscope, a protein would look like a telephone cord that is tangled up around itself.  As heat is applied, the protein begins to unravel.  This is denaturing.  As the heat continues, the protein will change its configuration, to the point of no return.  That is coagulation. Basically, once meat begins to cook, it can’t be “un-cooked”.

When meat is exposed to really high heat, like a grill or hot skillet, chemistry happens. The technical term for what happens is the Maillard (mai-yard) reaction. In the Maillard reaction, the glycogen and glucose that is stored in the muscle begins to react with the proteins and amino acids to create new compounds. 

As a chemist, I want to be able to demonstrate the reaction and point to the resulting compound which is the flavor.  Imagine being able to bottle that compound and then treat it as an ingredient in cooking!  Unfortunately, we are not that lucky.  During the Maillard reaction, hundreds, if not thousands of new compounds are made that contribute to that savory characteristic of meat we perceive to be flavor. 

The Maillard reaction does not just happen on the piece of meat. When searing a steak or pieces of meat, chefs will often talk of the “tasty bits” that are left on the bottom of the pan. The French have a term for those ‘tasty bits”, it’s called fond.  The process of deglazing is the addition of liquid to the pan in order to release the fond from the metal and dissolve it into the liquid. The fond is completely the result of the Maillard reaction.  As a chef, I will tell you – never, never, never skip deglazing.  You are just throwing away a tasty gift of the process when you do.

As long as we are on the subject of heat and meat, there is one kitchen myth that needs dispelling.  Contrary to popular myth, application of heat alone does not “seal in the juices “; rather, it is the combination of searing the meat in a hot pan and then allowing it to rest that results in a tender, moist cut. The myth is derived from the visible Maillard reaction on the surface which creates a crust; however, all that is happening is that the protein in contact with the pan is contracting as heat is applied.  This reaction forces the juices of the meat into the center of the cut.  The movement of the juices requires that the meat “rest,” or in layman’s terms, be removed from the hot cooking surface and placed on a cuttingboard to sit, unpunctured for a few minutes after cooking.  Resting allows the juices to redistribute throughout the meat.  If a piece of meat is not allowed to rest after cooking, cutting into it will cause all of those flavorful juices to run out of the meat and onto your cuttingboard or plate. While it may be tempting to slice into that beautiful steak hot-off-the-grill, remind yourself that “good things come to those who wait.”

While not yet explained by science, the Maillard reaction is some of the best chemistry you could conduct in the kitchen or on the grill. Flavor, color and even juiciness can be the rewards if you sear the meat well and let it rest for a few minutes before eating. So, fire up that grill and get your flavor on.

About Joe LaVilla

Chef LaVilla is the Academic Director for the Culinary Arts programs at the International Culinary School at the Art Institute of Phoenix. Besides being a Certified Executive Chef, Chef LaVilla also holds a certification from the International Sommelier Guild (ISG) as a Certified Sommelier. In addition, Chef LaVilla is experienced in food styling, food and wine pairing, the hospitality industry, culinary arts management, and more.

Before joining The Art Institute of Phoenix, LaVilla had been Executive Chef for Tucchetti restaurant in Phoenix. He has worked for Mark Tarbell as well as Wolfgang Puck. His credits include, “Faculty of the Year” award at The Art Institute of Phoenix; finalist in the Arizona Pork Council Taste of Elegance Competition; and author of the textbook “The Handbook of Wine, Beer and Spirits: A Guide to Styles and Service”.

Chef LaVilla received his Ph.D. in Organic Chemistry from the University of Rochester and his Bachelor of Arts degree, Cum Laude, in Chemistry from Cornell University. He also received an associate’s degree in Culinary Arts from the Culinary Institute of America, where he graduated with honors.