tortillas

Product Formulation Optimization #3

October 19, 2021 by Alan McClure

The Troublesome Yet Terrific Tortilla (Part 3)

In part 3 of our look at the troublesome yet terrific tortilla, following as it does from a general description of the tortilla quandary in part 1, and some specific details regarding the tortilla challenges anticipated in part 2, finally I’ll begin to explain how I approached the task of optimizing the formulation, or in simple terms, how I made the very best tortilla.

What Is “Best?”

As mentioned previously, I’ve already defined that I am speaking of wheat-flour-based tortillas; so my goal in optimizing a tortilla formulation is to produce the wheat-flour-based tortilla with the best organoleptic characteristics. It’s worth taking a moment to consider what I mean by “best.” In this case, I am considering only my own preferences, whether I’m talking about aroma, overall flavor, mouthfeel, or even appearance. However, if I were developing this tortilla for a regional restaurant chain, it would make sense to do consumer evaluation that includes a sample of the regular customers of that chain, and perhaps also consumers that the chain is trying to convert to customers. My specific preferences, for example, may or may not overlap well with those of the restaurant customers. But luckily, since the tortillas in question are for me, I can more simply consider my own preferences.

All Wheat-Flour Tortillas Are Not Created Equal.

Also, it is important for me to clarify that I want a tortilla that tastes great when fresh. I’m not at all concerned about storing the finished product on the shelf, or in the fridge or freezer. I want a tortilla that I can griddle now, eat, enjoy thoroughly, and then move on. If I were developing a tortilla for a grocery chain, I would have to reconsider this approach, because in that case the end consumer has little chance of buying the tortillas fresh and hot. They will need to be reheated out of necessity, and they will likely need to be able to remain free of mold for at least a week on the shelves, and perhaps longer. Such a tortilla would have characteristics that are dramatically different from the type I want to eat for my own enjoyment.

Are there Additional Constraints?

There are plenty of other details to consider. Do I want to work with ingredients available at the local grocery? Am I interested milling grain into flour? Does the tortilla need to be vegetarian? What types of equipment are available for processing and cooking the tortillas? And speaking of production constraints, while I’m willing to deal with dough that is a bit sticky or stiff and difficult to roll out in order to achieve a better tortilla, there is a limit to my patience. I don’t want to make my life 50% more difficult just to squeak in an extra 1% increase in improved mouthfeel. So, as I’m rating the various sensory characteristics of each tortilla, I can also consider rating things like dough stickiness, dough toughness, and perhaps overall workability.

Pulling Everything Together.

I’ve said that I want to optimize the formulation for a wheat-flour-based tortilla that is best according to my own preferences. I want to be able to make it at home with a 4’x4′ maple butcher block serving as the work surface, a wooden rolling pin, a 6-qt stand mixer, an induction range, a cast-iron skillet, and a spatula. I would also generally like to use ingredients that are readily available (e.g., King Arthur AP wheat flour, sea salt, and filtered tap water), but I’m willing to put in a little extra work to improve the quality of the added fat.

Ingredients.

For the fat in the tortillas, I’ll render my own lard from the backfat of locally raised hogs. As part of the rendering process, I’ll use a temperature high enough to brown the cracklings once they are void of fat, which adds additional roasted complexity to the lard’s flavor profile. At the end of the rendering process, I’ll also add some smoked bacon to give the lard a subtle smoky note. I will not be using plant-based oils in this recipe, as I know from experience that they have bland or off flavors in tortillas. I will also not be using baking powder. As mentioned in part 2, baking powder is quite a common ingredient in modern tortillas, but I would prefer to depend upon steam–from the added water–to leaven and lighten the texture of the tortillas. In my experience, the mouthfeel of the end product is better than when baking powder is used. So now I’ve clearly defined the constraints for this project. What’s next?

**Freshly griddled wheat-flour tortillas made with freshly rendered pork lard, filtered water, and sea salt**

A Product Optimization Experiment.

We now have to take our known constraints and design an experiment that will allow us to optimize the tortilla formulation. How should we proceed? One variable at a time? Often seen as the acronym OVAT, this is thought by most non-scientists to describe how experiments are run according to the scientific method. Actually, even some scientists believe this. But here’s the thing, it’s dead wrong. Even in a relatively simple food like our tortillas with only four ingredients (i.e., flour, water, lard, salt), changing the amount of one variable at a time, let’s say the flour, while holding all else constant, is likely to be, at best, an incredibly inefficient way to determine what the optimal tortilla recipe is, and at worst, will never find it at all. In short, OVAT has significant disadvantages. Arguably, the most important disadvantage is that important “interactions” usually exist in foods, and will be missed with the OVAT approach.

Interactions!

In this project, if we simplify for a moment to say that our only goal is to improve the flavor of the tortilla on a scale from 1-10, then any positive main effect would be one related to any of the individual ingredients that increases quality. For example, maybe more lard increases quality on average. That’s lard’s main effect. But what happens when water and lard are both present? Does water, in addition to having its own main effect on quality also impact the degree to which lard has a positive impact? If so, then that would be an interaction effect. It might be the case that with smaller amounts of water, lard is hugely positive in its impact, but with more water it makes a much smaller positive difference. It is immediately clear why interactions can cause huge problems with the OVAT approach; because if you only change one variable/ingredient at a time, you can’t determine if interactions exist. And guess what? Interactions almost always exist to some degree, and sometimes they are hugely influential. So what can we do about this?

Optimal Design of Experiments.

When the OVAT approach can’t be trusted to work, which is usually, instead we can rely on the considerable theory in the field of statistics that supports what is called “design of experiments,” along with modern computers and software, to produce an optimal experimental design. Such a design is able to help determine what the optimal formulation would be of a tortilla, again from the flavor quality standpoint defined above, but more than that, such a design even allows the experienced product development expert to determine the optimal formulation while considering several characteristics at the same time. This is sometimes called multiple objective optimization. How it does this is easier to show with an example than to explain in prose, so we’ll take a look at a tortilla-development optimal design in the final part of this series (part 4).

–Alan McClure

Product Formulation Optimization #2

September 28, 2021 by Alan McClure

The Troublesome Yet Terrific Tortilla (Part 2)

Continuing on with the product formulation optimization theme, using tortilla formulation specifically as an example, we dig in further. As a reminder, tortilla formulation is more complicated than it may at first appear. As I wrote previously:

“From the standpoint of the uninitiated, a tortilla seems a simple beast. As a plain product on its own there are no fillings or inclusions, no added flavors, swirls of color, or fancy shapes. Even the plastic bags in which they’re sold ten at a time are nothing special. But the phrase “deceptively simple” does exist for a reason. And one could reasonably argue that it was coined as a product formulation expert was doing some deep thinking about the common, yet commonly unimpressive, tortilla.”

In this recent post I also spoke about the two different types of tortillas (corn and wheat flour), and noted some of the complexities of both of them including nixtamalization in the case of corn tortillas, and the presence of gluten and necessary added fat in the case of the wheat flour tortillas. Clearly, when done well, both types of tortillas are fantastic, but my family was handed down a wheat flour tortilla tradition from my Mexican great grandmother Guadalupe Otila Macias, and since I was a wee child I’ve been truly mesmerized by this type.

Watching my grandmother mix and knead them by hand, roll them out with a flick or two of the wrist, and then bake them on top of a cast-iron griddle on the stove–the incredible smell–and then passing one steaming and blistered with flavor from hand to hand with nearly burnt fingertips, taking bites and smiling uncontrollably. These are some of the most powerful memories of my childhood. Why would I ever want to change a single detail in my original family recipe?

As I mentioned previously, wheat flour tortillas can be tricky because the gluten proteins in wheat (i.e., glutenin and gliadin) when hydrated, help to create a stretchy and springy dough that is notoriously hard to roll out. To produce a less tough and easier to roll tortilla, people traditionally added some amount of fat to the dough in the form of freshly rendered pork lard. The added lard reduces the overall gluten development, and the tortillas become more aromatic and the mouthfeel more tender and less chewy. And when everything is just right, the tortillas puff magically like perfect little pillows, making them even lighter in texture. But what about when everything isn’t just right?

tortillas freshly cooked — **Freshly griddled wheat-flour tortillas made with freshly rendered pork lard, filtered water, and sea salt**

The Baking Powder Bandage

The problem is that getting the ratio of ingredients just right can be very tricky. If it is even a bit off, or the griddle temperature is not optimal, or the tortilla maker is just not paying the right amount of attention, the tortillas can end up dense and unpleasant. The solution to this problem used by most is an addition of baking powder. It allows the tortilla maker a bit more flexibility in all of the important conditions. However, the texture of a baking-powder-risen tortilla is not quite the same as one without, and it has been written more than once by tortilla aficionados that the baking powder version is simply not as good.

The Vegetable Oil Blunder

Another problem is that as refined plant-based vegetable oils have become much cheaper, and good fatback from which to make lard has become less readily available in the marketplace, recipes have begun to call for either liquid oil or hydrogenated oil, also called shortening. These oil-based tortillas simply aren’t capable of tasting as good as those made from the roasted and rendered fat of flavorful hogs.

So, the modern homemade wheat-flour tortilla, which itself is scarce compared to the store-bought versions with little personality, is itself a shadow of its former glorious self. But if these changes to the modern tortilla have led to a poverty of quality, what is to be done about it? How can we possibly attempt to recreate a product formulation that most of us have never tasted?

I’ll explain how I approached this challenge in an effort to do just that. Stay tuned for más detalles in Part 3.

–Alan McClure

Product Formulation Optimization #1

September 15, 2021 by Alan McClure

The Troublesome Yet Terrific Tortilla (Part 1)

From the standpoint of the uninitiated, a tortilla seems a simple beast. As a plain product on its own there are no fillings or inclusions, no added flavors, swirls of color, or fancy shapes. Even the plastic bags in which they’re sold ten at a time are nothing special. But the phrase “deceptively simple” does exist for a reason. And one could reasonably argue that it was coined as a product formulation expert was doing some deep thinking about the common, yet commonly unimpressive, tortilla.

So where should we start to understand the product formulation challenge better? It’s often the case that the very best examples of foods are traditional ones. And certainly where tortillas are concerned, traditional versions are far better than the most familiar brands at the local grocer. For those who have had incredible tortillas, the kind that are calling out to be eaten, simply, steaming hot from the Mexican comal, fingers burning, we know this in our gut. But if one wants this beautiful experience far away from a Mexican market or abuela, is it even possible?

What is a tortilla anyway?

First, let’s simplify the issue. Tortillas come in two main types: corn- and wheat-flour-based. Corn tortillas are traditionally made from alkali-treated heirloom corn, called “nixtamal,” a Nahuatl term borrowed from the Aztec. This process, often referred to as nixtamalization, uses a relatively dilute solution of culinary lime, aka calcium hydroxide, in water to catalyze hydrolysis and conversion of various compounds in the corn kernels’ hull. This process makes the corn easier to digest, more nutritious, less likely to contain harmful mycotoxins, and most people would claim, myself included, more delicious. In fact, the flavor is so good, that traditional corn tortillas require nothing more than ground nixtamal, water, and bit of salt, to create a fabulous flat food fit for an Aztec king. But, as previously mentioned…

Corn is not the only way…

In northern Mexico and Texas, which also used to be part of Mexico, where wheat flour was more readily available, tortillas made from this grain were more common. And because the proteins in wheat, when hydrated, help to create a stretchy and springy dough that is notoriously hard to roll out, people added some amount of fat to the dough in the form of freshly rendered pork lard. The lard reduced the overall gluten development, making the thin disks of dough easier to roll out, and moreover, made the tortillas more aromatic and the mouthfeel more tender than chewy. And when the proportions of flour:water:lard are just right, the tortillas puff magically, making them lighter and more tender in texture, and giving the surface of the tortilla a deliciously mottled appearance, due to light charring of the steam-puffed pockets on the surface, thereby creating even more flavor–Maillard reaction pathways y’all.

Now, I’m a sucker for both types of tortilla, and I’ve made countless batches of both, nixtamalizing my own corn, experimenting with many of the countless heirloom Mexican varieties, and for the wheat tortillas, rendering my own lard, getting the roasted, almost smoky pork flavor just right. But I have to admit that having grown up with wheat flour tortillas in my family, a cultural contribution of my Mexican maternal great-grandmother, Guadalupe Otila Macias, who emigrated to Texas as a young girl, I have spent considerably more time thinking about, making, and certainly eating wonderful wheat flour tortillas. And I can assure you that even with four ingredients, they are tricky to perfect, or more technically, to optimize the product formulation.

But I’ll tell you what; recently I did just that. Stay tuned for más detalles in Part 2.

–Alan McClure