I grew up in a house the place rice was on the desk each single evening, and I’ve been cooking rice my complete grownup life, usually a number of occasions per 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 house cooks—significantly these of Asian descent, together with myself—swear will yield the right 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 house cook dinner whom I linked with over social media after placing out a request in search of knuckle-rice fanatics, says her late grandfather taught her the approach. “I can’t keep in mind when he confirmed me, however I’ve used it as a information since,” she says.
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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 after I didn’t know easy methods to 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 approach truly work? And in addition, extra critically: Does it work?
These questions first popped into my head after I watched my husband, who grew up in a family the place his Scottish and Ashkenazi Jewish dad and mom didn’t repeatedly cook dinner rice, try and observe my knuckle-rice directions. I confirmed him the way in which my dad and mom taught me, assured his rice would come out as good as mine. He adopted my instructions to a T, however his grains got here out mushy and overcooked. What had gone improper, I questioned, and was it potential that the knuckle methodology wasn’t as foolproof as I believed? I made a decision to seek out out.
What Occurs When You Prepare dinner Rice?
In an effort to perceive how the knuckle methodology works, we first want to know a pair basic items about what occurs whenever you cook 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 1 a part of rice by quantity,” writes Tim Chin in his primary white rice recipe.
This may occasionally strike readers who’ve cooked rice at the very least a number of occasions 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 fluctuate, however roughly one-and-a-quarter cups of water per one cup of dried rice is widespread. The rationale for that is evaporation. A 1:1 ratio of rice to water by quantity could also be preferrred, however that is solely true if not one of the water escapes as steam. In the true world, since some quantity of water boils off in a cloud of vapor, it’s important to add a little bit additional otherwise you’ll find yourself with too little water and grains of crunchy rice.
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Hainanese Rooster Rice Set
And right here we get to a different tough 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 cook dinner one cup of rice, however you do not want two-and-a-half cups of water to cook 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 regardless of in the event you’re cooking one, two, or three cups of rice; you may at all times lose about one-quarter cup of water as steam.
Understanding the logic behind the knuckle methodology requires first understanding these primary details of absorption and evaporation throughout the cooking of rice.
How Does the Knuckle Technique Work?
One of many important 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 whenever you put dry rice in a pot and add solely sufficient water to simply submerge the rice, you’ve got roughly arrived at that primary, good 1:1 ratio of water to rice by quantity. Which means, the quantity of all of the house between the dry rice grains that’s crammed by the water is roughly equal to the quantity of the dry rice itself. She then goes on to elucidate that by putting 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 simply 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 bother whenever you get into bigger and bigger portions of rice,” she says. And that, my mates, is why the knuckle methodology can work whatever the batch measurement, whereas merely multiplying a base ratio doesn’t.
Based on Yu, the strategy 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 shouldn’t be solely that your finger is the right size for measuring the water to be evaporated, however that everybody’s finger is the proper 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 may 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 strategy actually was in apply. 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 checks, one based mostly solely on finger measurements and quantity calculations, the second a extra real-world examination of the knuckle rice methodology put into apply.
Check 1: Relying on Fingers
With ruler in hand, I set off across the workplace, asking mates, colleagues, and strangers if I may measure their index fingers. (This elicited some unusual seems to be—you’d be amazed how uncomfortable this could make some individuals.)
Quickly, I had the measurements of the primary phalanx (to make use of the anatomically appropriate time period) of the index fingers of 19 individuals. Even in such a small pattern measurement, I may 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 an excellent larger vary. However let’s work with what we have got—for instance six millimeters is how a lot human index fingers fluctuate when measured from the tip to the highest to the knuckle (which I outlined as essentially 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? Effectively, that is so simple as calculating the quantity 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 numerous 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 peak? Many readers could also be struggling to recollect their highschool (center college?) geometry formulation, so I will remind you: The quantity of a cylinder is calculated by multiplying pi by the sq. of the radius, after which multiplying that consequence by the peak.
That is the maths:
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Let’s simply stroll by 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 consequence 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 remaining quantity of 36.65mL for each 1mm of peak 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 swap again to the inane (but acquainted!) chaos of US customary—that is about 7 teaspoons for each 1mm of pot peak.
Now let’s return to the 6mm vary I might 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 quantity 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 whenever you take a look at the messiness of the real-world state of affairs by which one has to stay their finger right into a pot and add water?
I examined that too.
Check 2: You Can Lead a Knuckle to Water…However Can It Make Good Rice?
On this check, I requested a bunch of individuals so as to add water to 1 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.
| Water Quantity (Grams) | Finger Size (CM) |
| 689 | 2.4 |
| 639 | 2.5 |
| 534 | 2.4 |
| 518 | 2.3 |
| 448 | 2.7 |
| 425 | 2.5 |
| 421 | 2.3 |
| 405 | 2.4 |
| 348 | 2.7 |
| 295 | 2.4 |
| 259 | 2.5 |
| 236 | 2.6 |
As you possibly can see above, essentially the most water added was 689 grams (virtually three cups), and the least quantity of water was 236 grams (about one cup). For comparability’s sake, if we have been working with a ratio of 1 1/4 cups water for 1 cup of rice, the aim can be 295g water right here. Whereas one individual completely nailed it, a number of got here in beneath and plenty of extra added an excessive amount of water—shockingly an excessive amount of. However even when we take away essentially the most excessive measurements from the highest and backside ends of the vary, we’re nonetheless 639g on the excessive finish and 259g on the low finish, which is a big vary.
Even weirder, the quantities of water added do not appear to correlate with finger size within the methods we might count on. As an alternative of the quantity of water added going up as finger size will increase, my knowledge exhibits no clear correlation between finger size and water amount.
What’s up with that? Effectively, for starters, my pattern measurement is small. Maybe my knowledge can be higher with 100 knowledge factors as a substitute of the 12 I’ve right here. One other chance is that we did not standardize the approach nicely sufficient throughout contributors. I had advised them to put their index finger towards the mattress of rice and pour water as much as the primary knuckle joint, nevertheless it’s potential not everybody interpreted these directions the identical manner. Possibly some allowed their fingers to sink down into the mattress of rice, held their finger at an angle, and/or judged the “first knuckle” inconsistently (there are, in any case, a whole lot of creases on the pores and skin of our knuckles—who’s to say the place the road actually is?).
Even when my knowledge has a excessive diploma of confounding elements, the check underscores a crucial level: The knuckle rice methodology is supposed to be foolproof, and but it could simply be interpreted and utilized in another way with drastic penalties, and that is not even factoring within the assured variation in water quantity we’d count on to see simply from the variations in finger size.
Is the Knuckle Technique Rubbish?
Although I’ve by no means been let down by the knuckle methodology, our check outcomes present that, in actuality, this methodology shouldn’t be a constant approach to make rice. That’s to not say that the knuckle methodology doesn’t work; it probably works nicely for the people who find themselves accustomed to it, like those that grew up watching their household put together rice this manner or have finished it so many occasions that they’ve developed an instinct for the correct quantity of water to make use of over time.
One among our contributors, Vy Tran, tells me that she makes use of the knuckle methodology (which she picked up from her mother) each day, however doesn’t suppose it’s constant. “As soon as you determine a sure water degree and may eyeball it, it really works nicely,” she says. “However often several types of rice will want trial and error of how a lot water.”
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It seems that the knuckle methodology works not as a result of there’s one thing exact about it, however as a result of the individuals who use it have developed a deep familiarity over time, turning into increasingly attuned to the nuances of the strategy with out realizing it isn’t simply the strategy, however their expertise, that makes it work. And so it was for the individuals they discovered from, and the individuals they discovered from, going again generations.
Though I’m a baker and pastry chef by coaching and swear by the dimensions, I’m nonetheless deeply dedicated to the knuckle methodology. The truth that this methodology works for therefore many individuals—regardless of the massive variation in knuckle lengths and the quantity of water used—means that apply does, certainly, make good. Nevertheless it’s greater than apply: It’s the embodiment of data and expertise one beneficial properties over time within the kitchen. There may be an artwork to creating a fantastic pot of rice, one that’s constructed on an intuitive really feel discovered by our fingers by doing one thing lots of, if not 1000’s, of occasions, usually in methods we’re not even acutely aware of. The knuckle methodology could not actually be one of the simplest ways to cook dinner rice, nevertheless it’s additionally undeniably one of the simplest ways to cook dinner rice.
So does the knuckle methodology work? It may—however not for the explanations everybody thinks.