Billions Use This Methodology for Cooking Rice—However Does It Work? We Examined to Discover Out

I grew up in a house the place rice was on the desk each single night time, and I’ve been cooking rice my whole grownup life, typically a number of instances every week. And every time, I make it the very same manner: I wash the grains in water till it runs clear, pressure the rice, then place it in a pot. I contact the highest of the rice utilizing my pointer finger and add simply sufficient water to achieve my first knuckle. This system is extensively known as the “knuckle methodology,” which many residence cooks—notably these of Asian descent, together with myself—swear will yield the proper ratio of water to rice, no matter batch measurement, proprietor of finger, or measurement of pot. Each time.

“The knuckle methodology has at all times been foolproof,” meals author Jess Eng tells me. “I picked it up from my mother who picked it up from her mother.” Eng grew up watching her dad and mom make rice utilizing the knuckle methodology, and in the present day she prepares rice the very same manner, although she’s unable to supply a proof of why she thinks it really works. Meredith Wong, a Chicago-based residence prepare dinner whom I related with over social media after placing out a request in search of knuckle-rice fanatics, says her late grandfather taught her the method. “I can’t keep in mind when he confirmed me, however I’ve used it as a information since,” she says. 

Like Eng and Wong, I discovered to make rice by watching my dad and mom and grandparents. I don’t keep in mind when, precisely, they taught me, nor do I keep in mind a time in my life once I didn’t know make rice. I’ve been doing it for therefore lengthy that it feels deeply intuitive. With the knuckle methodology, I could make fluffy, tender grains in any pot and in any kitchen. However how does the method truly work? And in addition, extra critically: Does it work?

These questions first popped into my head once I watched my husband, who grew up in a family the place his Scottish and Ashkenazi Jewish dad and mom didn’t usually prepare dinner rice, try and comply with my knuckle-rice directions. I confirmed him the way in which my dad and mom taught me, assured his rice would come out as excellent as mine. He adopted my instructions to a T, however his grains got here out mushy and overcooked. What had gone fallacious, I puzzled, and was it attainable that the knuckle methodology wasn’t as foolproof as I believed? I made a decision to search out out.

What Occurs When You Prepare dinner Rice?

So as to perceive how the knuckle methodology works, we first want to know a pair staple items about what occurs once you prepare dinner rice. Because the rice cooks, the grains soak up water and the starch inside swells and softens. However there’s solely a lot water rice can soak up earlier than it reaches optimum gelatinization—any extra and the rice blows out and turns to mush. “That ratio sits at round one a part of water to at least one a part of rice by quantity,” writes Tim Chin in his primary white rice recipe.

This may occasionally strike readers who’ve cooked rice a minimum of a couple of instances of their lives as odd: Most recipes do not name for equal volumes of rice and water, they name for barely extra water than rice. Ratios range, however roughly one-and-a-quarter cups of water per one cup of dried rice is frequent. The explanation for that is evaporation. A 1:1 ratio of rice to water by quantity could also be perfect, however that is solely true if not one of the water escapes as steam. In the actual world, since some quantity of water boils off in a cloud of vapor, you must add just a little additional otherwise you’ll find yourself with too little water and grains of crunchy rice.

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And right here we get to a different difficult element: This additional quantity of water that is wanted when cooking rice—let’s name it the evaporation quotient—doesn’t scale proportionally because the batch measurement goes up. Which means, you might want one-and-a-quarter cups of water to prepare dinner one cup of rice, however you do not want two-and-a-half cups of water to prepare dinner two cups of rice. That is as a result of, given roughly comparable pot sizes, the quantity of water that evaporates is kind of the identical irrespective of in case you’re cooking one, two, or three cups of rice; you will at all times lose about one-quarter cup of water as steam.

Understanding the logic behind the knuckle methodology requires first understanding these primary information of absorption and evaporation throughout the cooking of rice.

How Does the Knuckle Methodology Work?

One of many major arguments for why the knuckle methodology works hinges on the concept because the rice batch measurement goes up, the water scales up with it in a ratio of 1:1 by quantity, however the evaporation quotient doesn’t—it simply will get added on prime.

In a YouTube video, Julie Yu, a scientist on the San Francisco museum Exploratorium, tells viewers that once you put dry rice in a pot and add solely sufficient water to simply submerge the rice, you’ve got kind of arrived at that primary, excellent 1:1 ratio of water to rice by quantity. Which means, the amount of all of the area between the dry rice grains that’s crammed by the water is roughly equal to the amount of the dry rice itself. She then goes on to elucidate that by inserting the tip of your index finger towards the floor of the mattress of rice and bringing the water as much as that first knuckle, you might be efficiently measuring the evaporation quotient.

“As a result of the quantity that you just want for absorption scales [with] the quantity of rice, however the quantity that escapes by evaporation doesn’t, a ratio methodology goes to trigger you hassle once you get into bigger and bigger portions of rice,” she says. And that, my associates, is why the knuckle methodology can work whatever the batch measurement, whereas merely multiplying a base ratio doesn’t.

In accordance with Yu, the tactic is so reliable as a result of the size of your index finger from tip to first knuckle simply occurs to be spot-on for measuring the evaporation quotient. However after all her level just isn’t solely that your finger is the proper size for measuring the water to be evaporated, however that everybody’s finger is the right size for this. She claims, fairly confidently, that the “first phase of adult-sized fingers are remarkably comparable,” including that if viewers didn’t consider her, we might measure for ourselves—which is strictly what I did.

The Testing

The idea behind the knuckle methodology is sensible: Volumes of water and rice scale in a 1:1 ratio, however the additional water wanted to account for steam doesn’t. However after watching my husband, I had doubts about how “foolproof” the tactic actually was in observe. Are our fingers actually comparable sufficient in size to ensure such constant outcomes? The excellent news is that that is simply measured with a ruler and calculated utilizing primary geometry.

I made a decision to run two exams, one based mostly solely on finger measurements and quantity calculations, the second a extra real-world examination of the knuckle rice methodology put into observe.

Take a look at 1: Relying on Fingers

With ruler in hand, I set off across the workplace, asking associates, colleagues, and strangers if I might measure their index fingers. (This elicited some unusual seems to be—you’d be amazed how uncomfortable this will make some folks.) 

Quickly, I had the measurements of the primary phalanx (to make use of the anatomically appropriate time period) of the index fingers of 19 folks. Even in such a small pattern measurement, I might see that not everybody’s finger was the identical size. In my survey, I documented a six millimeter vary between the smallest finger phase (2.3 centimeters) and the most important phase (2.9 centimeters, belonging to our very personal editorial director Daniel Gritzer). Since this was a survey of solely 19 index fingers, one can safely assume {that a} bigger variety of measurements would have uncovered a good greater vary. However let’s work with what we have—as an instance six millimeters is how a lot human index fingers range when measured from the tip to the highest to the knuckle (which I outlined as probably the most pronounced crease on the palm-side of the finger).

The following query is: How a lot of a distinction in water quantity can a six millimeter distinction in phalanx size make? Nicely, that is so simple as calculating the amount of a cylinder, as a result of what’s a pot if not a cylinder that is closed on one finish and open on the opposite? I figured the most typical pot measurement for many at-home batches of rice can be about three quarts. After taking a look at a lot of 3-quart pots on-line I settled on 8 1/2 inches as an excellent common diameter, which any sane individual would instantly convert to metric (216mm) earlier than doing any math.

The query then turns into: What is the quantity of a 216mm-wide pot for each one millimeter of top? Many readers could also be struggling to recollect their highschool (center faculty?) geometry formulation, so I will remind you: The amount of a cylinder is calculated by multiplying pi by the sq. of the radius, after which multiplying that outcome by the peak.

That is the mathematics:

Let’s simply stroll via the above in case it is inflicting the math-phobic amongst us psychological paralysis.

• First we calculate the radius: The radius is half the size of diameter. The pot’s diameter is 216mm, so the radius is half that at 108mm.
• Then we multiply pi by the sq. of the radius: 108mm squared is 11,664 sq. millimeters, and we multiply that by 3.1416, getting 36,651.85 sq. millimeters.
• We multiply this outcome by the peak: Multiplying 36,651.85 sq. millimeters by 1mm provides us a quantity of 36,651.85 cubed millimeters.
• As a final step, let’s convert these cubed millimeters into milliliters: This will get us a last quantity of 36.65mL for each 1mm of top in a typical 3-quart pot.

Translated to teaspoons—as a result of, sure, after the simple mathematical great thing about the metric system, we’re gonna change again to the inane (but acquainted!) chaos of US customary—that is about 7 teaspoons for each 1mm of pot top.

Now let’s return to the 6mm vary I would documented when measuring index finger segments: If each millimeter of water in a 3-quart pot holds about 7 teaspoons, then a 6mm vary in finger phase size can alter the amount of water in a rice recipe by 42 teaspoons. That is greater than 3/4 cup!

Let me spell that out: The pure variation in a human finger can change the quantity of water added to the rice by greater than 3/4 cup, which is a big quantity contemplating we solely need about 1/4 cup of additional “evaporation quotient” water when cooking rice.

This isn’t excellent news for the declare that knuckle rice is a foolproof methodology. However that is additionally simply based mostly on finger measurements and calculations on paper. What occurs once you have a look at the messiness of the real-world state of affairs wherein one has to stay their finger right into a pot and add water?

I examined that too.

Take a look at 2: You Can Lead a Knuckle to Water…However Can It Make Good Rice?

On this take a look at, I requested a bunch of individuals so as to add water to at least one cup (200 grams) of dry jasmine rice in a 3-quart pot utilizing the knuckle methodology, weighing how a lot water was added every time.