If there is a food that is more versatile than pasta, I’m not sure what it is. The sheer taxonomy of it alone boggles the mind. Fresh and dried, filled and unfilled, extruded or rolled, hollow or solid—those are just the forms. Then there are the preparations—tomato sauces of a million varieties, pesto, cream sauces. And yet, despite—or perhaps because of—that ubiquity, pasta is constantly simmered in myth and folklore. In this article we intend to dispel some of those myths, and to tell you how to use actual tools, rather than folklore, to achieve perfect pasta.
- Pasta history and background
- Pasta science
- Difficulties of pasta cookery
- How to cook pasta
- Pasta al pomodoro recipe
Pasta history and background
Pasta was not introduced to Italy from China by Marco Polo in the 13th century. Both written records, as well as archaeological evidence, suggests that pasta was made from wheat or its relatives in Italy for centuries before that time. While Polo may have brought some noodles back with him from his journeys, by no means was he the means of their introduction to the people at large.
Pastas in various forms may go back as far as the 4th century B.C, but because these “edible pastes”(a literal translation of what some pastas were called in Italy for a long time) were the food of the common people, there is little record of them.
In America, we most often associate pasta with spaghetti, though that is a particular shape of pasta. And we also mostly associate it with tomato sauces, though those are a relatively recent addition to the Italian menu canon. In fact, the first recorded recipe for a tomato sauce for pasta comes from an 1839 Italian cookbook, Cucina teorico pratica, by Ippolito Cavalcanti.
The root of Pasta’s popularity in the States stems primarily from the vast migration of Italians, especially from Naples, to the USA in the late 1800’s. They brought with them an appetite for pasta that was, for the most part, served by import for decades. But due to interrupted supplies of pasta imports during the First World War, pasta production became a real thing in America in the 1910s and 20s. To produce the pasta, farmers in the Dakotas began growing durum wheat to meet the demand. In fact, to this day most of the wheat grown for pasta, even in Italy, is grown in the American Midwest.
Durum wheat is important because it is exceptionally high in protein (gluten), which gives the pasta the structure it needs to dry and reconstitute effectively. Which brings us to the science of pasta.
Science of pasta: the interplay of starch and protein
When pasta is added to boiling water, the starch granules in it start to gelatinize. These granules are tightly bound chains of sugars that swell and loosen as they absorb hot water. By all rights, they ought to swell, release from each other, and disperse into the surrounding water, and the only thing keeping them from doing so is the gluten matrix into which they are embedded. That’s why durum flour is important.
Durum semolina (small, coarse flour granules of wheat endosperm that are harder than the rest of the wheat) has a very high gluten content, and the gluten it contains is of a less elastic variety. This lack of elasticity is important for forming the pasta, just as a springy dough would be hard to shape properly. But the strength of the gluten matrix holds the starch of the pasta together while it cooks.
As the water gelatinizes the starch on the surface of the pasta, deeper layers of the dried noodle are exposed to water, and so on down. The result is an analog to the temperature gradients about which we so often write, but with varying degrees of water absorption from the surface of the pasta on down to its center, instead.
Cooking the pasta al dente means stopping the cooking when the center of the noodle still remains slightly underdone and offers some resistance to chewing; at this point, the noodle surface is 80-90% water, the center 40-60% (somewhat moister than freshly baked bread).”—Harold McGee, On Food and Cooking, pg. 575
The amount of water that pasta will absorb is “1.6–1.8 times its weight” by the time it is done. If not for the rigid structure of the durum proteins, the pasta would literally disintegrate. This is why you should never attempt to make pasta out of cake flour; the starch to protein ratio is just all wrong.
You would think a food with so few ingredients would be simple to prepare. But pasta’s preparation can be fraught with problems, including boil-overs and clumping. However, a little scientific thought and the right tools can help you overcome these obstacles.
When the pasta cooks, of course, some of the surface starches do free themselves from the noodle, which is why pasta water becomes cloudy. If your pasta water is boiling rapidly, the starches in the water can link up enough to inflate with steam and become bubbles. If those bubbles go unchecked, the water can boil over the top of your pot.
What can you do to prevent this from happening? First, use the right pot.
A low-walled pot must be filled close to the brim to accommodate both your pasta and the water in which to boil it. If you only have one inch of “headspace,” it can easily be overwhelmed with starchy foam. A taller stockpot or pasta pot is best for pasta cookery for two reasons: it allows room for the boiling water to rise without going over the top and it allows for enough water to be present to dilute the starches. If the starches in the water are more dilute, they will have a harder time forming foam structures, and the foam they do form will be weaker and easier to break up.
“It’s generally recommended that pasta be cooked in 10 or more times its weight of vigorously boiling water (around 5 quarts or liters water per pound/500 gm).”—Mcgee, pp. 575–576
Incidentally, the longer the pasta cooks, the more starches are leeched into the water. By draining the pasta as soon as it is done (see below), you prevent higher concentrations of starch from entering the water. Overcooked pasta is more likely to boil over.
Another way to prevent boil-overs is to add a small glug of oil to the water. The oil breaks up the surface tension of the water, causing the bubbles to disperse. Some will argue that oil can form a slick on the surface of the noodles that will later prevent sauce adhesion, and this is a valid argument. But depending on your final preparation, that may not be a problem.
One older, tried-and-true method for preventing a boil-over is to lay a wooden spoon across the top of your pot as you cook. The spoon literally pops the bubbles as they rise, and can help prevent a boil over.
Aside from using a big enough pot with enough water, though, one of the most important ways to prevent pasta from boiling over is to never put a lid on your pasta. Here’s why:
There is a thermodynamic principle called the “ideal gas law,” that you may have forgotten about since high school physics. And it says that the pressure times the volume of a gas is proportional to the amount of the gas multiplied by its temperature and a known constant:
P is pressure, V is volume, n is the number of molecules in the system, R is the ideal gas constant and T is temperature. Because of their proportional nature, if one variable on one side of the equation increases, there must be an equivalent increase in a variable on the other side. So if the temperature of a system increases without the number of molecules shrinking, then either the pressure or the volume of the system must also increase.
In a pasta water bubble, the pressure remains fairly constant (starch bubbles aren’t known for their ability to handle increased pressures). So if the temperature increases, it’s going to be the volume that increases or, more importantly, if the temperature decreases, then the volume must decrease.
We boiled two identical pots of pasta, one with the lid on, one with the lid off, tracking temperatures in and just above the surface of the water using a ChefAlarm® with optional waterproof needle probe in the water and a Thermapen® over the surface. While the water temperatures in both pots followed the same heating and cooling curves, the temperatures of the air above the water were vastly different. The lidded pasta had an air temp of 204°F (96°C)—the boiling point of water at ThermoWorks HQ (see our Boiling Point Calculator)—while the air just above the surface in the uncovered pan fluctuated between 145–163°F (63–73°C).
When steam bubbles at 204°F (96°C) were met with much cooler 145–163°F (63–73°C) air, they cooled, and a decreasing T meant a correspondingly decreasing V. The cool air shrinks the bubbles. But if the steam bubbles find an environment beyond their walls that is the same as that within their walls, they can grow and build on each other without any thermal hindrance. Every time I use a lid, my pasta boils over; but if I leave the lid off, it is rarely a problem.
Clumping in pasta is caused by improper treatment of the noodles, especially in the first seconds of cooking. When the starches start to gelatinize as soon as the pasta hits the water, the surfaces can absorb all that lies between them. Noodles will have nothing left between them to lubricate them, and the starches will act as glue sticking them together. To prevent this, be sure to use enough water so that the noodles can have room, but also be sure to stir the pasta for the first minute or so in the water. This will allow water to flow evenly around the individual noodles and for gelation to begin without getting gluey. This is another reason for always adding your pasta to water that is already rapidly boiling: the active water agitates the noodles and moves them apart from each other.
How to cook pasta
With the problems of boiling over and clumping dealt with, there’s one big question that still remains unanswered: how do you know when pasta is done? Some people say to pull a noodle out and throw it against a wall. If it sticks it’s done. But I say, hogwash. Cooking pasta is simply a matter of time. If you add pasta to boiling, salted* water, you should cook it according to the time on the package.
If that sounds like common sense to you, then you probably get great pasta results all the time. Most people that I’ve talked to about this are actually oblivious to the fact that the time on the package is the best time to cook the pasta. Even pastas of the same shape from different brands may have widely varying cooking times. These variances can be due to manufacturing techniques, including pasta-wall thickness.
Pasta companies have a vested interest in you enjoying their product, so they put a lot of time and effort into figuring out just how long each shape that they make should be cooked. Use an Extra Big and Loud Timer to reap the benefits of their hard work! Get plenty of water boiling hard, add the pasta, and if the box/bag says to cook it for 8-10 minutes, set the timer for 8 minutes and focus on the rest of your dinner.
To make pasta that really sings, you have to take the sauce into account. For most sauces, including tomato and cream sauces, it’s best to finish cooking the pasta in the sauce. Set your Extra Big and Loud Timer for one minute less than your target time. Have your sauce simmering on the stove, ready to use when the timer goes off. Grab a measuring cup and dip out a cup or so of pasta water from the pasta pot and set it aside. Drain your pasta and add it to the sauce.
Add about a half cup of pasta water to the sauce and start to stir the pasta together with the sauce rather vigorously over high heat. Cook until the sauce isn’t runny and it clings to the noodles.
Why add pasta water? When you add the pasta water to the sauce, you bring some of that freed starch from the pasta. That starch will thicken the sauce naturally, just like adding corn or potato starch to a sauce will. As you stir the pasta itself into the sauce, you will also agitate more starches off the noodles, adding them to the thickening equation. And as the pasta continues to cook and starches continue to gel, the water that will be available to the pasta will be sauce, and it will actually absorb the flavors of the sauce into the noodles themselves. Done properly, this will yield a silky- textured sauce that clings gently to the noodles. Top it with Parmigiano or Pecorino cheese and you will have a plate of pasta that cost you 78¢, but would cost you $12 at a fine Italian restaurant.
* Salting pasta water is a must. The salt infuses into the noodles as you cook them, flavoring them far more than adding salt afterward can. Imagine cooking bread with no salt, but then sprinkling a little salt on each slice. It’s just not the same. Use about a teaspoon of salt per quart of boiling water.
Pasta al pomodoro recipe
- 2 28 oz cans whole peeled tomatoes (San Marzano are best)
- 4–6 cloves garlic, crushed
- 4 Tbsp olive oil
- 2 sprigs of fresh basil
- salt and pepper
- 1 lb pasta of your choice
- Hard grating cheese of your choice for serving
- Put a large pot of water on to boil with 1 tsp salt per quart of water.
- As you wait for the water to boil, start preparing your sauce.
- Crush the tomatoes by hand for a rustic approach, or whiz them in a food processor or blender for a more even consistency.
- Chiffonade the basil by rolling up several stacked leaves and slicing thinly across the roll.
- Heat the olive oil in a sauté pan over medium-high heat.
- Once the oil is shimmering, add the garlic and cook until it just starts to brown.
- Add the tomatoes and basil to the pan and stir to combine. Add pepper and a little salt, but remember that you’ll be adding salted pasta water later, so don’t overdo it.
- Let the sauce simmer and thicken somewhat as you cook the pasta.
- Add pasta to the water, and stir it. Set the Extra Big and Loud Timer for the time indicated on the package minus one minute.
- From time to time, stir the pasta as it cooks.
- When the timer sounds, scoop out a cup of pasta water and drain the pasta.
- Add pasta to simmering sauce along with 1/2 cup of the pasta water. Keep the rest of the cup of water in case the sauce needs loosening later.
- Stir the pasta, water, and sauce together over medium-high heat for 1–2 minutes to finish cooking the pasta and to coat it well with the thickened sauce.
- Serve with grated cheese for topping
By being aware of the thermal realities of your pasta pot, and the way that the starches in it react, and by using an easy and loud timer like the Extra Big and Loud, you can master pasta cookery. It’s a simple food that doesn’t need your stress. It just needs plenty of salty water and a good kitchen timer.
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