This is How the Tortilla Chip Crumbles

Since I had a wholesome batch of salsa made with homegrown veggies, I felt the need to find the best partner for it, namely, a mound of crispy and flavourful homemade tortilla chips.  Now, it might seem like a simple task, but one question immediately came to mind: must they be fried?  It is usually a given in modern recipes, but I was thinking that maybe baking could be a nice and healthier alternative, especially since traditional totopos (Mexican colloquialism for crispy rounds or triangles made with corn dough) are baked in a clay oven with no oil.  The next question was whether to start with dough (masa) or restaurant style, with already-made tortillas.  Since I have covered making tortillas from masa in a previous post, I picked the latter choice; in addition, a tortilla chip is technically a crisped piece of tortilla, whereas one made directly from dough is called corn chip (such as Fritos™).

I had a package of yellow corn tortillas in the fridge, so that is what I used, assuming that my results would equally apply to white or blue corn tortillas.  While reviewing recipes, all of them agreed on one step, which was to start with stale, at least day-old tortillas, and many directed to further dry the cut sections on the kitchen counter indoors, or under the sun, either outdoors or by a window sill.  I also cut the tortillas into two shapes commonly used: short strips, and pie sections. Once I established my variables (drying method, oil addition, heat source, and shape) I got to work.  I sliced 4 tortillas into 12 short strips each, and another four into 8 pie sections, as shown below:

Then I arranged them on a tray and let them dry on the kitchen counter until they felt dry and made a “scratchy” sound when brushed against each other; I checked at 14 hr, and there was still some moisture.  By 48 hr. they looked and felt completely dry (notice the smaller size of the chips on the right, compared to the sticky note):

I reserved half of the chips, and took the other half outside, along with freshly sliced tortillas from the fridge, two cut into strips, and two into triangles.  It was a beautiful sunny and dry day, so by the time I went back inside to get the camera and came out to take the photo below, some pieces were already starting to curl, encircled by the power of the sun!

I checked them after 2 hr, and then after another 2 hr, and thought they were dry enough:

I was amazed by how much the pieces from the fridge had shrunk in only 4 hr, almost looking the same size as the pieces that had been pre-dried for 48 hr. I also noticed that these chips had developed layers (photo left, above).  Finally, I took another four tortillas from the fridge, and sliced half into strips and half into triangles.

All this slicing and drying generated four different kinds of tortilla sections: group I) from the fridge, no drying; group II) dried on the kitchen counter for 52 hr; group III) dried on the counter for 48 hr plus sundried for 4 hr; and group IV) sundried for 4 hr.  Each group was divided into four portions and placed in small paper plates (photo, right).

 

 

 

The first portions from each of the four groups were left untreated, as control (photo below, top left); the second were baked without oil at 375°F for 5 minutes (top right); the third were brushed with vegetable oil and baked at the same temperature and time (bottom left); and the last portions from each group were fried in a pan with vegetable oil over medium heat until golden brown (bottom right):

Then, I placed them back onto their paper plates and arranged them on a 4×4 grid (the fried portions at the bottom row were placed on ceramic plates to protect the tablecloth from grease stains):

These sixteen samples, resulting from the permutations of drying and cooking methods, and taking one strip and one pie section from each, were now ready for the taste test, as shown below:

Where A) control samples; B) Baked with no oil; C) Brushed with oil and baked; and D) Fried

I decided to be the first tester, not wanting to unnecessarily vex the family with unsavoury portions; I sprinkled some salt over my samples to make the experience more enjoyable.  Unsurprisingly, all the “A” control samples were unfit for human consumption, being cold from the fridge, or hard as cardboard from drying.  Baking without oil for “B” resulted in chewy texture for the no-drying chips from the fridge (group I), and too hard for the other three groups; even worse, the flavour for all was of plain tortilla, and very little colour had developed.  The addition of oil before baking for “C” somewhat improved the flavour and colour, but not the texture, still chewy for group I, and too hard for the other three, although group IV, the sundried chips, were a little lighter and crispier.  Portions “D” were the best across all groups, with well developed flavour, and crispy texture; in more detail, the pieces from I (no-drying) were very light and crispy.  The groups dried on the counter (II and III) were harder, and also had a tendency to burn more easily, rather than turning golden brown. Finally, the sundried pieces (IV) were golden brown, crispy and with some separation of layers, and I thought that they had absorbed less oil than the other groups, especially the no-drying from group I.

I presented my family only with the last two rows: “C”, brushed with oil then baked at 375°F for 5 minutes, and “D”, fried.  The results were clear-cut: The sundried/fried chips (D-IV) were declared the best; close second were the no-drying/fried (D-I), and a far third, the sundried/brushed-with-oil+baked (C-IV).  There were no significant differences between strips and pie sections, so shape was not a factor for these tests.

So, what happened?

I thought the no-drying/fried chips (D-I) were very close to the freshly fried chips served at many Mexican restaurants but, when compared to store bought triangles, they had a much lighter crunch and better flavour.  When tortillas are cooked on a grill, they develop two thin membranes, one on either side.  If they are then fried without pre-drying, the moisture in the tortilla gets heated really fast in the oil’s high temperature, well above water’s boiling point; this causes steam pockets between the membranes, creating a layered structure as they crisp:

When baked, the evaporation process takes place in air and it is much slower, factually steaming the chips and creating the unpleasant and chewy texture in groups B-I and C-I.  Chips left indoors dried even more slowly, at room temperature, so the evaporation created no pockets, making the layers stick together; this is why all groups from II and III were the least appealing, and the hardest.  For the sun-dried chips, as mentioned before, drying occurred quickly, showing signs of curling even after just a few minutes; at the end of the four hours under the sun, the chips had developed layers, a similar process to the fast heating in oil.  When subsequently baked or fried, the thin layers already present had a chance to crisp individually, absorbing less oil, and hence, creating the lightest, most appealing crunch of all.  Brushing with oil before baking (C) still made a big difference from baking without (B), though, because browning and flavour depth were enhanced.

In conclusion:

Frying is the method of choice to achieve tortilla chips with the best flavour, colour and texture.  On the brighter side (pun intended), pre-sundried chips produced the lightest and crispiest texture after frying, and if not possible, it is better to fry the chips right away rather than drying them indoors at room temperature.  If baking is still chosen, sundried chips brushed with oil will produce the best results for this alternative.

In the kitchen:

To prepare homemade, light and crispy tortilla chips, with well developed flavour and golden-brown colour:

• Use day-old corn tortillas
• Slice into strips or pie sections
• Dry under the sun for a few hours, when possible, or use right away
• Fry until crispy and golden brown
• Sprinkle with salt, to taste

If baking, brush sundried chips with vegetable oil, and brown at 375°F, being careful not to burn the chips.

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Science Tidbits:

Oh tragedy, why are fatty foods so tasty?
Cooking with fat produces an enhanced experience for all our senses.  Fried foods will have, first of all, an inviting scent, carried and enriched by the oil particles where the food is being prepared.  Moreover, nothing compares to the crunchy sound and satisfying sensation from biting into a crispy treat.  Flavours in fried food develop well thanks to the reaction of amino-acids and peptides occurring rapidly between 140 to 165 °C (280 to 330 °F), well above the boiling point of water, but a typical range for frying.  This reaction, known as the Maillard reaction, is also responsible for the non-enzymatic browning that creates the visually appealing golden-brown colour on heat treated food, including fried goods.

But why do we crave fatty foods?
This seems to be a remnant from ancient times when energy storage was crucial for survival, so consumption of fat would trigger the brain to produce a positive response.  In some sense, fried foods may be regarded as more nutritious than boiled, for example, when a veggie tempura is fast fried, compared to a boiled-beyond-recognition vegetable; by frying, a short exposure to heat with a protective batter coating will result in a higher vitamin and other nutrients content, lost in the cooking water of the boiled alternative.  It has also been argued that we have evolved to appreciate cooked food over raw, because it will be safer to consume, and for example, the protein in a well browned burger will be absorbed more easily than from a rare steak.

However, not everyone craves fatty foods equally. Apparently, there is a “fat detection” gene, regulating the number of fat-detecting proteins in a person’s tongue. People with less of this protein, unable to taste fat easily, will crave it more, and some scientists believe this will in fact predispose an individual to obesity.

And how about fat substitutes?
Tasting fat that does not exist will trigger a metabolic response to absorb whatever calories enter the digestive system, so it is probably better to eat real fat in moderation (yay, fried tortilla chips, here I come!)