Well, after several posts that struggled to reach the platonic ideal of a tortilla chip, I think I’ve finally found the answer! It’s nice to get that elated feeling, of “yes, science works!” In any case, read on for the key to making awesome tortilla chips that are light and crispy just like my favorites, the beautiful and delicious Peppers chips featured below.
In previous experiments, I had noticed that a lot of variability in chip quality was probably due to frying technique. I kept temperature as constant as possible, and compensated for variations in temperature by not fixing myself to a single frying time- I would wait till the chips were just starting to get golden, and then take them out. But several things made me want to control temperature:
1) My anal-retentive, detail-oriented personality
2) Chips that began to turn golden brown at the edges were still uncooked in the middle
3) My ideal chips weren’t brown at all, so using “golden brown” as a cue for removing chips would always lead to overcooked chips.
Thus, I snagged a thermocouple (fancy temperature measuring device) from the lab, set my phone to stopwatch mode, and cued myself for an experiment. Now, to finally answer the question, how do frying time and temperature affect the quality of tortilla chips?
What makes an “ideal” chip?
I had a very clear goal in mind- I wanted chips that looked and tasted like the ones from my favorite Mexican restaurant (featured at the top of the post). This means the chips would be barely browned, but still have a really firm snap to them.
This probably means sticking to a low frying temperature. Browning is typically caused by the Maillard reaction, which is very likely to happen above 300ºF. The Maillard reaction can actually occur at almost any temperature, but it’s inhibited by water. So something needs to be especially dehydrated to brown at temperatures below 300ºF, and even then it can take a while.
Therefore the solution to my goal probably involved frying the tortillas at a low enough temperature that no Maillard reaction would occur, but long enough to completely fry the tortilla to a good crisp. If such a temperature/time combination even exists was an open question, since longer frying can eventually produce the Maillard reaction even at lower temperatures, so crisping might always be followed by significant browning.
Since we’ve previously found that the type of starting tortilla has little effect on the final quality of the chip (as long as it’s made of corn), I decided to just use the Guerrero brand corn tortillas. I made a hybrid frying oil of somewhere around 75% Wesson vegetable oil and 25% extra virgin olive oil.
I cut the tortillas into six equal pieces, set the fryer to the right temperature, and then chucked in the tortillas for the necessary frying time. In all tests, chips were fried one at a time, and flipped half-way through the frying process. Chips were then left to cool and drain their residual oil on a paper towel.
I took a picture of all the chips to quantify browning, then smashed the chips with a pyrex pie bowl to see how crispy the chips were. I also did some assorted tasting of the chips. You know, for science.
Note that my range of tested frying temperatures (275ºF-435ºF) goes above and beyond the typical recommended frying temperature range for tortilla chips (325ºF-400ºF, based on my internet browsing).
First, I found more browning as frying time increases, as expected. I also found that chips browned faster at higher temperatures, also no surprise but pretty cool to see how dramatic the effect was. Temperatures below 350ºF generated no discernible browning for any of the frying times tested here.
The smash test also showed some really interesting results. Generally, browning tended to correlate with highly brittle chips, but the correlation wasn’t perfect. For example, the 30-60 second chips at 425ºF browned but did not smash well. Also, the 180-300 second chips at 300ºF did not brown at all, but smashed into pieces beautifully.
Most importantly, note that there were some chips with no browning that also fractured quite a bit in the break test- just like my ideal chip! A taste test confirmed that chips cooked at 300ºF for 180 seconds tasted almost exactly like my target chip should taste! There were some other close seconds, the 120 seconds at 350ºF chip was pretty good, and the 90 second chip at 375ºF was decent, but anything beyond that had the desired crispiness but was far too browned.
Some general rules of thumb
1) No chips cracked at all with only 30 seconds worth of frying. All these chips were at least partially undercooked. This even holds true for the test at 425ºF: although partially browned, this chip is definitely not crispy. Generally, higher temperatures tended to produce either unevenly cooked chips or evenly burnt chips.
2) 275ºF is just too low for frying. Anything below 120 seconds was more of a greasy tortilla than anything else: even the 300 second test produced a chip that you could fold in half without breaking in two.
3) Tastewise, brown generally meant bad for tortilla chips. Golden brown was ok, but anything noticeably brown had a distinct burnt flavor.
So, to get a perfectly light and crispy chip, it seems the trick is doing a long fry at a temperature low enough to not trigger the Maillard reaction. The best result was 3 min at 325ºF. I’m almost tempted to go back to my original trick of spritzing the chips with water, to see if the additional water content can impede the Maillard reaction, allowing a shorter frying time at a higher temperature. Five minutes is a long time to wait for each batch of chips, especially when I’m without a true deep fryer.
But I think I’m too fried out to go for another huge fry-a-thon… at least for now.
Anyone else up for the challenge? Are light and crispy chips possible with a shorter frying time?