They say the best things in life are the simplest, and few things speak truer to this than the quesadilla. At its purest form it is two heated tortillas full of melted cheese in the middle. The quesadilla originated in Mexico and can be modified to include a variety of meats and vegetables. But at the end of the day, you can’t beat the winning combination of cheese and bread. Quesadillas are commonly made using frying pans, but this method includes the obvious hassles of watching the quesadilla to make sure it doesn’t burn while also flipping it to cook both sides evenly. It was these predicaments that gave birth to the quesadilla maker. A quesadilla maker is essentially the cousin to the panini press: a machine that uses two heated plates to cook both sides of a sandwich. Panini presses have been modified into waffle makers and breakfast sandwich makers, but quesadilla makers are specifically designed with circular-shaped heating plates to perfectly fit tortillas.
Creating a Quesadilla Maker may seem simple in theory, but there are several variables that need to be accounted for. Anyone that has enjoyed a quesadilla knows that the biggest tragedy is finding out that your cheese didn’t fully melt while cooking. A close second tragedy is having a quesadilla that is too crunchy or burnt on the outside. This suggests that the variable that needs controlling in this process is the temperature of the heated plates of the quesadilla maker. Although this control is not necessarily essential to the device’s operation, avoiding both aforementioned tragedies would spare many a quesadilla lover a lot of heartache. So, we have the task at hand: we want to design a two-plated heating system that will both heat up the quesadilla high enough to melt the cheese fully, while not too high that will burn the tortillas. As time is of the essence for all quesadilla-lovers, we also must make sure that the quesadilla maker finishes in a timely fashion in order to have little wait time for cheesy-goodness. Our God-challenging machine will be fittingly named: the Queso-Roboto. While our task may seem impossible for some, we are chemical engineers. We live for the challenge, and more importantly, for the quesadilla.
According to Sargento, a global cheese superpower, cheddar cheese begins melting at approximately 66 oC. Cheddar cheese is undeniably one of the best cheeses for use in quesadillas, and is included in the recipes of many great chefs like superstar Paula Deen. We will use this melting temperature as the lower limit of our possible control range.
The upper limit of the possible temperature range is capped by the temperature at which the tortillas burn. Fun Fact: burning actually occurs when all of the water in a food has evaporated. This does not occur at a particular temperature, so an experiment to find the temperature that cooks the best quesadilla would have to be performed. This experiment would not only provide us with a set point for temperature, but it would also provide us with an ample amount of quesadillas. While some would burn during the experiment, we believe that a burnt quesadilla is better than no quesadilla.
In the experiment, our quesadilla research and development mavens would make quesadillas at temperatures increasing from 66 to 100 oC. Each trial would be run in triplicate to have an assessment of reproducibility, and panelists of a double blind study would rate the quesadillas. Rated attributes would be evenness of cooking, crispness of tortillas, cheese stretch length, perfect bite, overall beauty, Bue-No or Bue-Yes, and “wow” factor. The cook temperature determined to yield the most perfect quesadilla would be used as the set point temperature of our quesadilla making device. As with any self-respecting experiment, a randomized DOE run order will be developed. This will later be analyzed to note trends, reoccurring errors, outliers, and all the fixins.
A trial example and scoring is as follows-
- Trial #5
- Evenness of Cooking: 5/5
- Crispness of Tortilla: 4.5/5
- Cheese Stretch Length: 12.3 cm
- Perfect Bite: Si
- Overall Beauty: Eva Longoria
- Bue-No or Bue-Yes: Bue-Yes
- “Wow” Factor: Ah Dios Mio!
In order to control the temperature of the plates, the variable that needs to be manipulated is the amount of current flowing into the quesadilla maker from the source of electricity. This can be practically done, by implementing a feedback loop that uses a temperature sensor to measure the temperature of the sizzling quesadilla, and compare it a set point. The controller will use any difference between the actual temperature and the experimentally determined set point to adjust the amount of current to either increase or decrease the temperature of the plates.
A possible disturbance hindering one from achieving quesadilla perfection is the fact that the press is not completely closed when it is operating. Because of this, heat is able to be exchanged with the air around the open edges of the press. Since the temperature of the air is cooler than the temperature of the inside of the quesadilla maker, heat is exchanged between the quesadilla and the ambient air. This creates a difference in temperature between the edges and the middle of the quesadilla. To account for this, the apparatus could be designed to have two separate heating mechanisms, and two different control systems. Each heater would have its own temperature sensor and set point, and would report back to its own controller. This would allow the temperature of the outside of the quesadilla maker to be slightly hotter than the inner temperature to allow for more even cooking despite heat exchange with the environment.
Another possible disturbance would be the blessing, and curse, of endless human creativity. The trials we are performing, consisting of purely tortillas and cheddar cheese, do no account for the free-thinkers and rebels of the quesadilla world. Our current model only works assuming that the quesadilla in question is in its most basic form. In world full of meats, vegetables, sauces, and guac, we will never be able to predict and prepare for every combination the Queso-Roboto will encounter. Instead, we will create a set time length and timer for the quesadilla models used in our trials, and leave it up to the discretion of the user to keep it in for longer periods of time. Though the insides will change, our original controller for the temperature limit and outside air effects should still be viable for these potential quesa-monstrosities.
Sources:
Cheese melting temp: http://www.sargentofoodservice.com/trends-innovation/cheese-melt-meter/
Paula Deen recipe: http://www.foodnetwork.com/recipes/paula-deen/cheese-quesadillas-recipe.html