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Great Popcorn Experiment

Popcorn kernels

On Tuesday I celebrated our first anniversary here at Food With Legs.  One of the things I dig most about writing this website is the opportunity to look back at what I was cooking in the past and re-examine techniques.  I was inspired by some talk on Twitter by Michael Ruhlman (author of Ratio, Charcuterie, and others) this week to take another look at my stovetop popcorn recipe.

I no longer lead a microwave-free lifestyle but I still like the idea of making popcorn on the stovetop.  Ruhlman pointed to his post from January 2009 where he gives his recipe for making stovetop popcorn or “pot popcorn” as his son calls it.  His big thing is not preheating the oil before the kernels go in.  My method uses the pretty typical three kernels as a thermostat to judge when the oil is sufficiently preheated.  The difference seems interesting, Ruhlman usually knows what he’s talking about (and seems pretty adamant in this case), and popcorn is cheap so I consider this an ideal situation for a head-to-head, slightly scientific Pop Off.

Room temperature canola oil and popcorn goes into the pan together

Method 1 (The Ruhlman): corn and oil goes into a cold pan; over high heat; shake pretty constantly; lid on tightly; remove from heat when popping stops plus fifteen seconds.

The three thermostat kernels

Method 2 (Corn With Legs): oil into cold pan with three kernels; over medium heat until three kernels all pop; add rest of corn and shake intermittently; lid on slightly ajar; remove from heat when popping stops plus fifteen seconds

Hypotheses: There are two reasons I buy into preheating the oil.  First, hot oil is much less viscous than cold oil–visualise swirling the oil in a very hot pan versus cold oil–and this means it will be easier to more evenly and completely coat all of the kernels in oil.  Secondly, Alton Brown teaches us (referencing Harold McGee, I’m sure, but I can’t which Good Eats episode it was so can’t check) that the reason we cook with oil (as well as for lubrication) is conduction–the oil acts like a fluid pan.  If we can take full advantage of this characteristic by preheating the oil and then more easily surround each kernel in its own pan.

I admit that this experiment is not just a straight comparison of hot oil versus cold oil because my method uses medium heat (instead of Ruhlman’s high heat) and has the pot lid set slightly ajar to allow some steam to escape.

Ruhlman aims our goal at zero unpopped kernels.  I agree that this is the best objective method of judgment and I’ll also count those half-popped dental landmines in the negative column.

I think that the preheated oil will do a better job of even popping but will take a noticeably longer amount of time.

Two roughly identical 1/4 cup portions of popcorn

Materials: The Ruhlman Method makes enough for four using a cup of popcorn and three tablespoons of canola oil.  (Note: This seems like a large serving size. It’s one and a half times the recommended serving on the popcorn container and once you add in the half-ounce of butter per person and assume that half of the cooking oil stays on the popcorn we’re up to 365 calories per serving.)  I’ll test both recipes in a single serving portion of a quarter cup (60 g) of popcorn with 3/4 tablespoon of canola oil.

I know, I know the popcorn magnate in the glasses is evil and owned by the even more evil ConAgra Foods but it’s now the only brand my Loblaws carries and that’s where I was shopping today so Orville Redenbacher it will have to be.  Also, unlike the microwaveable version this is corn–Orville Redenbacher’s specially-selected, possibly GM corn–with nothing added.

I’ll use the same Cuisinart 1.5 quart stainless steel pot for both tests, well-washed and cooled to room temperature between batches.  Working on the smallest unit of a gas range.

Popcorn popped using the cold oil method

Ruhlman Results: My hypothesis that the viscosity of the oil would cause a problem is confirmed.  At first the kernels stick to the pan and it took very vigorous shaking to get them moving and evenly coated.  I don’t know if this would have been a problem in the end if I didn’t bother with the vigorous shaking–would some have continued to stick and burn before popping or would they have released on their own as the oil heated?

Popping started at almost exactly the four minute mark and including the fifteen seconds after the last pop to make sure that everything was done the pot was off the heat at exactly the six minute mark.

Objective results of the cold oil method

Four kernels were left unpopped; an additional four kernels were unpopped enough that they couldn’t be eaten.

Subjectively, this is a very good product.  Light and a little chewy and those popped kernels in the middle of the bowl (thinking in a vertical sense) had an alright taste of the cooking oil.  (I assume this is because they tasted less like butter than the kernels on top which get the butter directly or the ones on the bottom that are used to scrape butter from the bowl.)

More popcorn, this made with the hot oil method

Corn With Legs Results: The thermostat worked as expected, the rest of the 1/4 cup of kernels went into the hot oil and after a couple tosses of the pan the popping was in full swing by the 4:15 mark.  To my surprise the popping had been done for fifteen seconds and this batch was in the bowl at the 6:10 mark, just ten seconds longer than the cold-oil version.

Objective results of the hot oil method

Three kernels were unpopped; two kernels were partly popped but inedible.

There are two types of popped kernels: Ones that are made of a series of attached complete and partial spheres and remind me of three-dimensional models of somewhat complex molecules; and those look like a miniature puffball and recall the shape of a Jiffy Pop bag.  The latter are, in my experience, less common but much more delicious.  I suspect that the puffball kernels are created by a more explosive single pop and while I didn’t count it seemed like the hot-oil version produced a few more of these.  Very subjective, I know.

Also on the subjective front I slightly prefer the taste of the hot oil version.  There were more well-done kernels (a good thing in the case of popcorn, I believe) that have that special flavour that has a passing resemblance to the crispiest cheese on a plate of nachos, or for the high brow crowd, a toasted Parmesan wafer.

Conclusion: Along the objective measure (unpopped kernels) my method barely won out.  I admit this was only one test and I don’t really think the margin was significant at three kernels.  Subjectively, I prefer the taste of the hot oil version because it offered more contrast and more kernels that tread that agonizingly fine line between perfectly cooked and burnt.  The hot oil version is also recommended by how comparatively hands-off it is for the first few minutes, freeing the cook to melt butter and pour drinks.  Both methods produce a very good product and stand head and shoulders above the microwave version.

Update: I have a post up about cooking popcorn in duck fat and flavouring it with worcestershire sauce or curry powder.  Take a look here.

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10 Comments

  1. ruhlman says:

    great experiment! thanks for doing and posting. only thing i disagree with is the viscosity comment. yes, it’s going to be viscous at first but as it gets hot, it’s just as fluid the legs version. at any rate, I think it makes sense that both methods work perfectly fine!

  2. denise ds says:

    Interesting! We’ve been on a popcorn kick the last few months and I’d passed the cold oil method on to hubby (our official popcorn chef) after seeing Ruhlman’s tweets. Last night we swapped the typical hot oil / vented top method for the cold method and our far from scientific findings (on electric stove) are thus: it went faster, more kernals popped, a few were slightly scorched (he says it’s because it went so fast he probably kept the pot over the heat for too long), the kernels were tough and cardboardy. He vented the top, so between that and overcooking, we can’t blame the method. You’ve inspired me to be more exact and test again. Though I’m not the popper, I would think that one benefit of the cold method is that you can leave the lid tightly closed, making the shaking easier. Looking forward to an excuse for more popcorn soon!

  3. [...] Whose making better popcorn? [...]

  4. Maria says:

    Hey I always do it the hot oil version and I love my pop corn like that!!! It was a good experiment!! thanks for sharing!

  5. foodwithlegs says:

    ruhlman: Thanks for the feedback. Both methods definitely work and produce near-identical results. In reference to the viscosity issue I meant that if the oil is already hot and less viscous it will be easier to coat all sides of every kernel and hopefully get them to pop quickly without burning.

    denise: I’m not sure how much of a difference the vented lid makes. For shaking I just tap it into fully-on position, shake, and re-vent. Also, at least for the amount of corn I was using in the pot I was using a natural venting mechanism occurs when the popcorn expands enough to pus the lid up. See Ruhlman’s blog post for a fairly spectacular photo of this in action.

    Maria: Thanks for commenting.

  6. Thom says:

    Consider what is going on inside the kernel…I have a theory:
    *Remember the kernel pops only when it has enough steam-pressure inside.

    With cold oil the interior of the kernel heats gently (much like sous vide, but much faster). The interior will likely spend more time exposed to heat before popping and if the germ can soften (I’m not sure) it will have more time to do so before exploding.

    With hot oil the kernel will be heated rapidly and spend less time in the oil, less time exposed to heat (and internal steam).

    If the hot oil does actually pop more of the puffballs, perhaps the center of the kernels benefit from less heat/time exposure. If that really is the case, cold kernels may create more puffballs than room temp. The only problem with this theory is that considering the size of the kernels and the fact that they pop at approximately the same temperature, the difference in heat/time exposure is probably negligible.

    At least testing this theory will be tasty.

  7. foodwithlegs says:

    Thom: Thanks for commenting. I think the difference between the puffballs and the molecules is that with the molecules pressure has built slightly more slowly or for some reason one point in the kernels hull is pierced first. The wikipedia article on popcorn (http://en.wikipedia.org/wiki/Popcorn) has some interesting information. Apparently the puffballs are known, in industry jargon as “mushrooms” while what I call molecules are known as “butterflies”. They say that the butterflies have a better mouthfeel–I disagree–and that the corn’s genetics play a large role in determining the ratio of one to the other but also that, “Growing conditions and popping environment can also affect the butterfly-to-mushroom ratio.”

    Maybe I’ll try to find an appropriately-sized Corningware pot so that I can take a better look at what is going on during the popping process.

    Finally, in answer to popular (mainly offline) demand here is my popcorn recipe, simply stated. For each person measure out a very scant 1/4 cup (40 g. or 3/16 or a cup to be precise) of kernels. Heat two teaspoons of canola oil (also per person) over medium heat with three kernels (total, NOT per person) in a covered pot. When the three kernels have popped add the rest of the popcorn and shake. Replace the pot’s lid, left slightly ajar. Shake periodically, especially once the popping starts so that the unpopped kernels fall to the bottom. Remove from heat within fifteen seconds of the last pop. Use your judgment on what counts as the last pop since waiting fifteen seconds after a rogue pop may cause already popped kernels to burn. Serve with melted butter (about 1/2 oz per person) and fine salt, or your preferred topping.

  8. John Bailey says:

    A real popcorn aficionado would never use oil. Bacon grease is the only proper way to pop popcorn!!! Go back and begin again with the proper ingredients (and all the better reason to have it heated before putting in the kernels)!!!

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