The Maillard Reaction

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One of the most important flavor-producing reactions in cooking is the Maillard reaction. It is sometimes called the “browning reaction” in discussions of cooking, but that description is incomplete at best. Cooked meats, seafood, and other protein-laden foods that undergo the Maillard reaction do turn brown, but there are other reactions that also cause browning. The Maillard reaction creates brown pigments in cooked meat in a very specific way: by rearranging amino acids and certain simple sugars, which then arrange themselves in rings and collections of rings that reflect light in such a way as to give the meat a brown color.

The important thing about the Maillard reaction isn’t the color, it’s the flavors and aromas. Indeed, it should be called “the flavor reaction,” not the “browning reaction.” The molecules it produces provide the potent aromas responsible for the characteristic smells of roasting, baking, and frying. What begins as a simple reaction between amino acids and sugars quickly becomes very complicated: the molecules produced keep reacting in ever more complex ways that generate literally hundreds of various molecules. Most of these new molecules are produced in incredibly minute quantities, but that doesn’t mean they’re unimportant.

The Maillard reaction occurs in cooking of almost all kinds of foods, although the simple sugars and amino acids present produce distinctly different aromas. This is why baking bread doesn’t smell like roasting meat or frying fish, even though all these foods depend on Maillard reactions for flavor. The Maillard reaction, or its absence, distinguishes the flavors of boiled, poached, or steamed foods from the flavors of the same foods that have been grilled, roasted, or otherwise cooked at temperatures high enough to dehydrate the surface rapidly — in other words, at temperatures above the boiling point of water. These two factors, dryness and temperature, are the key controls for the rate of the Maillard reaction.

High-temperature cooking speeds up the Maillard reaction because heat both increases the rate of chemical reactions and accelerates the evaporation of water. As the food dries, the concentration of reactant compounds increases and the temperature climbs more rapidly.

caramelized carrots 4

Temperatures need to be high to bring about the Maillard reaction, but as long as the food is very wet, its temperature won’t climb above the boiling point of water. At atmospheric pressure, only high-heat cooking techniques can dry out the food enough to raise the temperature sufficiently. It’s not the water that stops the reaction, but rather the low boiling point at normal, sea-level pressure. In the sealed environment of a pressure cooker, the Maillard reaction can, and does, occur. This is something we exploit when making soups, like in our Caramelized Carrot Soup, or purees, like the broccoli puree in our Brassicas recipe. Adding baking soda to the pressure cooker raises the food’s pH (making it more alkaline), which also helps. Chinese cooks often marinate meat or seafood in mixtures containing egg white or baking soda just before stir-frying.

So, in boiled, poached, and steamed muscle foods, an entirely different set of aromas dominates the flavor. Drying and browning the surface first will, however, allow the reaction to proceed slowly at temperatures below the boiling point of water. This is why we sear frozen steak before cooking it in a low-temperature oven. Searing food before vacuum sealing and cooking sous vide can add depth to the flavor of sous vide dishes. This step should be avoided for lamb, other meats from grass-fed animals, and a few other foods in which presearing can trigger unwanted reactions that cause off-flavors and warmed-over flavors to form when the food is later cooked sous vide. We recommend searing those foods after cooking them sous vide.

Blowtorch-cropped

One of the challenges to getting the Maillard reaction going is getting the surface hot and dry enough without overcooking the underlying flesh, or at least overcooking it as little as possible. Cooks have developed several strategies to this end, some simple and some fairly baroque.

One strategy that works well is to remove as much water from the surface of the meat as possible before cooking it (via blotting or drying at low temperature). Fast heating using deep fryers, super-hot griddles and grills, and even blowtorches are also helpful tactics, such as when we deep-fry chicken wings.

You might think that raising the temperature even higher would enhance the Maillard reaction. It does up to a point, but above 180 °C / 355 °F a different set of reactions occur: pyrolysis, also known as burning. People typically like foods a little charred, but with too much pyrolysis comes bitterness. The black compounds that pyrolysis creates also may be carcinogenic, so go easy on charring your foods for visual appeal.

Adapted from Modernist Cuisine

Modernist Cuisine at Home Nominated for Awards

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We are thrilled to announce that Modernist Cuisine at Home has been nominated for a James Beard Award in the “General Cooking” category. Also nominated in that category are Canal House Cooks Every Day and What Katie Ate.

In 2012, winning the James Beard Award for Modernist Cuisine in the categories “Cookbook of the Year” as well as “Professional Cookbook” was one of the highlights of our year. We are very much looking forward to the award ceremonies. The award winners for cookbooks will be announced on May 3, 2013.

Modernist Cuisine at Home was also recently nominated for an International Association of Culinary Professionals (IACP) award in the category of “Food and Beverage, Reference/Technical.” In that category, The Art of Fermentation and Mastering Artisan Cheesemaking were also nominated. Last year, Modernist Cuisine won three IACP awards—in the “Professional Kitchen Books” category, the “Design” category, and also their newly created “Visionary Achievement” category.

On top of that, our CHOW.com video series, MDRN KTCHN, was nominated in the “Short Video Series” category. Kitchen Confidence on Food52.com and Master Class on Saveur.com were also nominated.

We are deeply honored to have been nominated for both the James Beard and IACP awards. Congratulations and best of luck to all other nominees!

Is It Safe to Cook with Plastic?

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Since writing Modernist Cuisine and Modernist Cuisine at Home, we’ve been asked many times to comment on the safety of cooking in plastic bags. Many of our sous vide recipes, from our Sous Vide Salmon and Rare Beef Jus to our Cranberry Consommé and Scrambled Egg Foam, require vacuum-sealing or using a zip-top bag. Similarly, many of our recipes that utilize microwaves, such as our Microwaved Tilapia, Eggplant Parmesan, and Microwave-Fried Herbs, require plastic wrap.

According to the latest research, the safest plastics for use with food are high-density polyethylene, low-density polyethylene, and polypropylene. Virtually all sous vide bags are made from these plastics, as are most brand-name food storage bags and plastic wraps such as Saran wrap. Polyethylene is widely used in containers for biology and chemistry labs, and it has been studied extensively. It is safe.

Less expensive, bulk plastic wraps sold to the catering trade are not as safe, however. These products are commonly made from polyvinyl chloride (PVC), which can contain harmful plasticizers that have been shown to leach into fatty foods such as cheese, meat, and fish. Legitimate concerns exist about food exposed to these plastics at high temperatures. Polyethylene-based plastic wraps are available at only slightly higher costs and do not raise such concerns. An easy way to spot the difference is to check that your cling wraps or plastic bags are rated microwave-safe. Bags and wraps made form polyethylene are generally microwave-safe, whereas those that contain polyvinyl chloride plastics generally are not.

Many professional kitchens use clear, rigid, plastic storage containers that are made from polycarbonate. While they are currently approved for food use, these plastics also may be a cause for concern because they contain bisphenol A (BPA), a chemical that can disrupt hormone activity and leach into foods and beverages. Cracks and crazing due to wear and tear increase the rate at which BPA leaches out of polycarbonates.

The bottom line is that bags made expressly for cooking sous vide are perfectly safe—as are oven bags, popular brands of zip-top bags, and stretchy plastics such as Saran wrap. If you remain hesitant to try cooking sous vide due to concerns over plastic, you can always use canning jars instead, but beware that cooking times will be longer.

—Adapted from Modernist Cuisine and Modernist Cuisine at Home

What Is Xanthan Gum?

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Some people are suspicious of ingredients with unfamiliar names, such as xanthan gum. We are frequently asked, “Aren’t your dishes chock-full of chemicals?” Well, yes, but all foods are, including the most natural and organic ones. But nearly all of those chemicals are derived from natural ingredients or processes that have been used for decades.

First discovered by USDA scientists in the 1950s, xanthan gum is fermented by plant-loving bacteria, characterized by sticky cell walls. It is no less natural than vinegar or yeast. We think xanthan gum is one of the best discoveries in food science since yeast.

It is used as a thickener or stabilizer in a wide variety of foods found on grocery store shelves. Many canned or prepared products contain xanthan gum: salad dressings, sauces, soups, and baked goods — particularly those that are gluten-free because xanthan gum can perform some of the same functions as gluten.

Xanthan gum is one of the most useful food additives around; it is effective in a wide range of viscosities, temperatures, and pH levels. It is easy to use, has no taste, and generally works quite well. And it can thicken liquids at extremely low concentrations – as little as 0.1% by weight can yield a thick liquid, and 0.5% by weight can make a thick paste (this is why it is best to weigh out xanthan gum with a digital scale rather than use volumetric measurements). Traditional thickeners like flour typically require far larger amounts to do a similar job. The quantity matters because the more thickener you have as a fraction of the total mixture the more likely it is to impose an undesirable texture and inhibit flavor.

Ready to try xanthan gum? Take a look at our recipe library for recipes for Spinach Pesto, Jus Gras, and Wasabi Cream. Check back later this month, when we’ll be showcasing more recipes from Modernist Cuisine at Home that use xanthan gum.

adapted from Modernist Cuisine and Modernist Cuisine at Home

How Whipping Siphons Work

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Whipping siphons are useful for making so much more than whipped cream. We use ours all the time for making fresh soda, speeding up marinating, infusing fruit, or topping a dish with foam or flavor or textural contrast.

Whether you’re carbonating, infusing, or foaming, there are a few basics you should know.

The siphon requires cartridges of gas, also called “chargers,” to pressurize the chamber holding the liquid. Carbon dioxide is best used for carbonation only. We use nitrous oxide for foaming, marinating, and infusing.

Whipping siphons were designed for aerating creams high in fat. Nitrous oxide dissolves much better in fat than in water, so high-fat liquids generally foam better in a siphon than low-fat ones do. You can, however, foam any liquid thick enough to hold bubbles. Add starch, gelatin, eggs, or agar to thin liquids to give them enough body for foaming.

Each cartridge holds 8 g of gas, can be used only once, and costs about 50 cents. Two cartridges are typically sufficient to charge a 1 L siphon. Use about 2% gas, or 8 g of gas for every 400 g of liquid—more if the liquid is low in fat.

If the seal on your whipping siphon is faulty, the gas will go in and then immediately start to leak. So listen closely as you charge it. You should hear gas filling the chamber—and then silence. Still hear hissing? Remnants of a previous foam might be causing a leak, or some part of the siphon could be damaged. Vent the siphon, remove the nozzle, unscrew the top, and take out the cartridge. Then clean these parts and the rubber gaskets thoroughly, and check to make sure that they are undamaged and properly seated.

All of these parts work in conjunction. In the diagram below, we have detailed each part and its role. Whipping siphons have several uses, but we have selected foaming for the purpose of this diagram.

  1. The rubber gasket keeps the dissolved gas from escaping. Make sure it’s intact and fits snugly along the top of the lid.
  2. The “empty” part of the siphon is filled with gas, which pushes on the liquid and forces it through the valves.
  3. Charging the siphon—that is, installing the gas cartridge so that it is pierced by the pin—increases the pressure inside the canister dramatically and forces the nitrous oxide to dissolve into the liquid. Shaking the container is crucial to ensure that the gas is evenly distributed.
  4. Hold the siphon upside down to help the gas propel the liquid from the siphon.
  5. The nozzle directs the flow.
  6. A rapid drop in pressure as the liquid leaves the vale causes most of the dissolved gas to emerge from the solution, thereby creating bubbles that expand into foam.
  7. A precision valve meters the forceful flow of liquid from the siphon.
  8. A disposable cartridge holds 8 g of nitrous oxide. The number of cartridges needed depends on the volume of the siphon, how full the siphon is, the fat content of the liquid to be whipped, and the temperature of that liquid. Generally two cartrdiges are enough for a 1 L siphon.

—Adapted from Modernist Cuisine at Home

Three Desserts You Can Make with a Whipping Siphon

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Whipping siphons are easy and fun to use. This Valentine’s Day, try wowing your special someone with a Modernist dessert created with nitrous oxide or carbon dioxide. Use our suggestions below for tasty ideas beyond the realm of whipped cream.

  1. Lemon Curd: Try using a whipping siphon instead of a pastry bag for piping your lemon curd. This will give it a foamy texture. Serve it atop raspberry sablé cookies or to make a pie using the flaky pie crust from Modernist Cuisine at Home.
  2. Microwaved Cake: This dessert is a cinch to make. You can use our recipe in Modernist Cuisine or Modernist Cuisine at Home or even just use a boxed mix. Dispense the batter from the siphon into a paper cup, microwave, and serve!
  3. Fizzy Fruit: We love using carbon dioxide to make fizzy grapes, but we’ve also used it to carbonate lychees and cranberries.

For most baking and savory applications, such as the Lemon Curd recipe, the Microwaved Cake recipe, and making whipped cream, you’ll need nitrous oxide (N2O) chargers. For carbonation applications, including the fizzy fruit technique, you’ll need carbon dioxide (CO2) chargers. Nitrous oxide dissolves into fats and is flavorless, as opposed to carbon dioxide, which dissolves in water and imparts a sharp flavor of carbonation. If you were to use CO2 instead of N2O when making whipped cream, for instance, the tangy carbonated flavor would fool your brain into thinking the cream had spoiled, which is not a pleasant sensation!

For more great dessert ideas, check out the Custards and Pies chapter of Modernist Cuisine at Home.

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How Pressure Cookers Work

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Pressure cookers are fantastic tools. They develop the characteristic flavors and textures of foods so quickly that what is conventionally a long, labor-intensive process becomes one hardly more time-consuming than a casual sauté. Risotto takes six minutes instead of 25. An intense chicken stock takes only 90 minutes. You can even pressure-cook food in canning jars or in oven bags or FoodSaver bags rated for high temperatures–which means grits and polenta, for example, no longer require constant stirring to avoid sticking. The high temperatures inside the cooker also promote browning and caramelization, reactions that create flavors you can’t get otherwise in a moist cooking environment. If you aren’t a believer, try our Caramelized Carrot Soup recipe.

A pressure cooker is essentially just a pot with a semi-sealed lockable lid and a valve that controls the pressure inside. It works by capturing the steam that, as it builds up, increases the pressure in the vessel. The pressure increase in turn raises the boiling point of water, which normally limits the cooking temperature of wet foods to 100 °C / 212 °F (at sea level; the boiling point is slightly lower at higher elevations). Because the effective cooking temperature is higher in the pressure cooker — as high as 120 °C / 250 °F — the cooking time can drop substantially.

Take a look below at our cutaway photo from Modernist Cuisine at Home. The letters correspond to an explanation of each part of the pressure cooker.

    1. High-pressure steam rapidly transfers heat to the surface of any food not submerged in liquid.
    2. A spring-loaded valve is normally open so that air can escape. As heating begins, expanding vapor pushes this valve up, closing off the vent. (At very high pressures, it rises farther and reopens the vent to release excess steam.) The valve regulates the pressure inside the cooker to a preset level: typically 0.7 or 1 bar / 10 or 15 psi above atmospheric pressure; this value is called the gauge pressure. At these elevated pressures, water boils at 114 °C or 121 °C / 237 °F or 250 °F, respectively. As soon as the cooker reaches the correct cooking pressure, reduce the heat to avoid over-pressurizing it.
    3. The sealing ring, typically a rubber gasket, prevents steam and air from escaping as they expand. This causes the pressure in the vessel to build as the temperature rises. Any food particles stuck in the seal can cause it to leak steam, so check and clean the gasket regularly.
    4. The lid locks with a bayonet-style mechanism that pushes against the sides of the cooker. Frequent over-pressurization can damage this mechanism and render the cooker useless. Other designs use bolts that clamp around the outside.
    5. The handle locks as well, to prevent the lid from opening while the contents are under pressure.
    6. There is too much liquid in this cooker. Generally, you should fill the pot no more than two-thirds full.
    7. Water vaporizes into steam, increasing the pressure inside the cooker as it heats. Because the boiling point of water depends on pressure, it rises too, just enough to keep the water and steam temperature hovering around the boiling point for the higher pressure. The pressure continues to rise until it is stabilized by the valve.
    8. Add enough water to the pot, either around the food or under a container of food elevated above the bottom of the pot, to enable plenty of steam to form.

Ready to start cooking? Check out our library for our Carnitas, Caramelized Carrot Soup, Risotto, and Garlic Confit recipes.

–adapted from Modernist Cuisine at Home

How to Scale a Recipe

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The Mac and Cheese recipe makes five servings, but you’re throwing a dinner party for nine people. You’re in luck: We’ve made it easy to scale our recipes up to greater yields (or down if you have fewer mouths to feed) by using baker’s percentages. Just follow these simple steps.

 

  1. Look in the scaling column of the recipe, and find the ingredient having a scaling value of 100%. Note the weight given. The 100% ingredient is usually the one that has the biggest effect on the yield of the recipe.
    Example: The 100% ingredient in the Mac and Cheese recipe above is white cheddar cheese.
  2. Calculate the scaling factor by dividing the number of servings (or grams) you want to make by the recipe yield.
    Example: This recipe yields five servings. If you are making nine servings, the scaling factor is 9 ÷ 5 = 1.8. (You can use the weight of the yield rather than the servings to calculate the scaling factor: If you want to make 1,100 grams of mac and cheese from a recipe that yields 800 g as written, the scaling factor is 1,100 ÷ 800 = 1.4.)
  3. Calculate the scaled 100% value for the recipe by multiplying the weight of the 100% ingredient by the scaling factor from step 2.
    Example: This five-serving recipe calls for 285 g of white cheddar, which is the 100% ingredient. To make nine servings, you will thus need 285 g x 1.8 = 513.0 g of white cheddar cheese. The scaled 100% value for this recipe is 513.0.
  4. Calculate the scaled weight for every other ingredient in the recipe by multiplying its scaling percentage by the scaled 100% value from above. You can ignore the weights and volumes given in the recipe—just use the scaling percentages.
    Example: The scaling percentage given for dry macaroni is 84%. Multiplying this by the scaled 100% from step 3, you find that 0.84 x 513.0 = 430.9. Similarly, you need 0.93 x 513.0 = 477.1 g of water or milk and 0.04 x 513.0 = 20.5 g of sodium citrate.

Because volume measurements are often rounded to the nearest spoon or cup, you should not multiply or divide volumes when scaling a recipe up or down. Instead, scale the weights as described above, and then weigh the ingredients on a digital scale.

Adapted from Modernist Cuisine at Home

Why Cook Sous Vide?

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Cooking sous vide is easier than its fancy name might suggest. You simply seal the ingredients in a plastic bag (you can also use a canning jar) and place them in a water bath, a combi oven, or any other cooker that can set and hold a target temperature to within a degree or two. When the food reaches your target temperature or time, you take it out, give it a quick sear or other finish, and serve it. That’s it.

The sous vide method yields results that are nearly impossible to achieve by traditional means. In the photo above, both of the tenderloins started at the same weight. The steak on the left was cooked in a pan to a core temperature of 52 °C / 126 °F, but more than 40% of the meat was overcooked. The other steak was cooked sous vide to the same temperature and then seared with a blowtorch to yield a juicier steak that is done to perfection from edge to edge.

Similarly, beef short ribs braised at 58 °C / 136 °F for 72 hours are melt-in-your-mouth tender, yet pink and juicy. And the delicate, custard-like texture of an egg poached at precisely 65 °C / 149 °F is amazing.

MCAH_RIBS_Opener_1077

Sous vide is especially useful for cooking meats and seafood, for which the window of proper doneness is often vanishingly small when traditional methods are used. When you fry a piece of fish, the flesh is most succulent and tender within a very narrow temperature range. Because the cooking temperature of the pan is at least 200 °C / 392 °F hotter than the ideal core temperature of the fish, the edges will inevitably be far more cooked than the center when pan-fried.

Chicken breasts and other poultry cuts and poultry products are often held at a target temperature for a different reason: to kill potential pathogens and improve the safety of the food.

The idea of preserving and cooking food in sealed packages is ancient. Throughout culinary history, food has been wrapped in leaves, potted in fat, packed in salt, or sealed inside animal bladders before being cooked. People have long known that isolating food from air, accomplished more completely by vacuum sealing, can arrest the decay of food. Packaging food also prevents it from drying out.

Although sous vide literally means “under vacuum” in French, the defining feature of the sous vide method is not packaging or vacuum sealing; it is accurate temperature control. A computer-controlled heater can warm a water bath to any low temperature you set, and it can keep it there for hours, or even days, if needed.

Such mastery over heat pays off in several important ways, most notably, freeing the cook from the tyranny of the clock. Traditional cooking with a range, oven, or grill uses high and fluctuating temperatures, so you must time the cooking exactly; there is little margin for error. With just a moment’s inattention, conventional cooking can quickly overshoot perfection.

When cooking sous vide, in contrast, most foods will taste just as good even if they spend a few extra minutes at a target temperature, so you can relax and devote your attention to the more interesting and creative aspects of cooking.

Precise temperature control and uniformity of temperature has two other big advantages. First, it allows you to cook food to an even doneness all the way through, no more dry edges and rare centers. Second, you get highly repeatable results. The steak emerges from the bag juicy and pink every time.

A final important benefit is that the closed bag creates a fully humid environment that effectively braises the food, so ingredients cooked this way are often noticeably juicier and more tender. Food cooked sous vide doesn’t brown, but a simple sear adds that traditional flavor where needed so that you can have the best of both worlds.

MCAH_RIBS_Lamb_Step4_MG_0702

We’ve been asked many times about the safety of cooking plastic bags. The bottom line is that bags made expressly for cooking sous vide are perfectly safe, as are oven bags, popular brands of zip-top bags, and stretchy plastic wrap such as Saran Wrap.

The plastic that these products are made of is called polyethylene. It is widely used in containers for biology and chemistry labs, and it has been studied extensively. It is safe. But, do avoid very cheap plastic wraps when cooking. These are made of polyvinyl chloride (PVC), and heating them presents a risk of chemicals leaching into the food.

Cooking sous vide isn’t complicated or expensive. In Modernist Cuisine at Home, we guide you through the various kinds of sous vide equipment and supplies available for home cooks, including how to improvise your own setup. Check back later in the week when we share such methods using equipment you probably already own.

 

— Adapted from Modernist Cuisine at Home and Modernist Cuisine

How to Calibrate Your Kitchen

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We’ve heard of chefs who claim that they can tell temperature by pressing a thermometer to their lips. Setting aside the problem that this technique could lead to a trip to the emergency room, the approach seems highly vulnerable to human error. Leaving temperature control to intuition is a recipe for disaster: dry and rubbery chicken, under-cooked fish, and scalded milk. What’s more, when cooking at low temperatures, being off just a degree or two can make your food not just unpalatable but downright dangerous to eat.

That’s why the most important tool in your kitchen is a quality thermometer, followed closely by a setup that allows you to set the temperature of the cooking environment with precision. With temperature under close control, chefs can relax and devote more of their creative brain power to flavor combinations and new textures.

Cooking food sous vide (sealed, in a low-temperature water bath) is one of the easiest and most affordable ways to achieve such control. Modernist Cuisine and Modernist Cuisine at Home include hundreds of our favorite recipes for sous vide dishes. We exploit this technique, for example, to slow-cook chicken to juicy perfection while also pasteurizing it, which requires a minimum holding time at the final temperature to knock any germs down to a safe level. It’s crucial to be able to trust your thermometer, because if it reads 60° C / 140 °F when the temperature is actually several degrees cooler than that, the chicken may not be fully pasteurized when you serve it.

Fortunately, high-quality thermometers are widely available and relatively inexpensive. We prefer digital thermometers because they are easy to read and switch instantly between Celsius and Fahrenheit. Moreover, better models, such as Thermocouple’s Platinum RTD probes, are accurate to about half a degree Celsius (a bit less than one degree Fahrenheit). Even inexpensive digital oven probes are accurate to within 1.5 °C / 2.7 °F, even at low temperature. Analog thermometers, in contrast, are all but useless at low temperatures, and spike-and-dial varieties typically vary up to 2.5 °C / 4.5 °F from the true temperature.

These accuracy numbers all presuppose that your thermometer is properly calibrated, not a safe assumption for many off-the-shelf products. So whenever you buy a new thermometer, calibrate it right away by using the simple, tried-and-true method of verifying that it reads 0 °C / 32 °F in water stirred with crushed ice and 100 °C / 212 °F in water at a full boil (but note that water boils at lower temperatures at elevations above sea level, so you may need to look up the normal boiling temperature at your location). Be sure the thermometer probe doesn’t touch the sides of the container, and give it a few minutes to settle on a final reading. If your thermometer hits these targets on the nose, it is suitable for sous vide and other low-temperature cooking methods. But if your thermometer is off by 2 °C / 4 °F or more, return it for a new one or take it to a professional to adjust it.

Once your thermometer is dialed in, you can move on calibrating other parts of your kitchen. You probably won’t notice a difference in your cooking if your oven is off by a degree or two, but if you can’t set an oven temperature below 200 °F / 95 °C, it isn’t suitable for dehydrating food or slow-cooking a frozen steak to medium rare. Because ovens are notoriously inaccurate at their lower ends, be sure to calibrate your oven at several lower temperatures before relying on it for slow baking or braising.

To calibrate your oven, you need a thermometer with a probe and digital display, tethered together by an oven-safe wire. Preheat your oven fully to its lowest available setting (give it a little extra time to settle), and then clip your probe to the oven rack so that the tip of the probe is near the center of the cavity and points upward and inward. Close the oven door, wait a few minutes for the oven to recover its temperature, and then note the temperature you set as well as the reading on the thermometer. Repeat with the probe placed near a back corner and then near the door. Next, increase the temperature by 30 °C / 50 °F, and repeat. It takes some time to record these measurements for the entire range of your oven, but you only need to do it once, and the resulting picture of your oven’s performance is invaluable. You may learn, for example, why your quirky oven burns cookies on the right side of the sheet even while cookies in the back left corner stay stubbornly raw. Oven walls radiate heat unevenly, so you should expect to see some temperature variations within the cavity. Once you know their magnitude and location, you can compensate for them.

As in an oven, the temperature inside your refrigerator is warmer on some shelves than others; the door compartments are often the warmest. This can pose a safety risk if the temperature in any part of the refrigerator exceeds 5 °C / 40 °F. It is wise to set your refrigerator to a temperature that causes lower shelves to drop below freezing if that is what must be done to keep the top shelves in the door within a safe range.

To test the temperature of your refrigerator, place glasses of water in it at various locations, including the door and the top and bottom shelves. Wait several hours and then measure the temperature of the water (take care not to let the probe touch the sides of the glass). Adjust the refrigerator setting if needed, and then repeat to confirm that all parts are at or below 5 °C / 40 °F.

When cooking or cleaning up after a meal, never put food in the refrigerator or freezer while it’s still hot. We used an infrared camera to visualize how much a bowl of hot leftovers warms the surrounding food in the refrigerator, and the results were shocking. The temperature can rise dramatically and stay above the safety zone for hours, long enough for food to spoil.

Finally, use a thermometer rated for subzero temperatures (many digital ones aren’t) to check the temperature inside your freezer. Generally speaking, the lower the better, because fast freezing produces the smallest ice crystals and the least damage to foods as they solidify. But as long as the temperature is -15 °C / 5 °F or lower, you needn’t worry about microbes multiplying in the frozen food.

No one claims that calibrating your kitchen is fun. But it is important, and once you’ve done it, all your cooking will go more smoothly. You can then focus more of your attention on the creative aspects of cooking without worrying so much about being thwarted (or even made ill) by the vagaries of temperature.

Click here to put your newly calibrated oven to use, cooking steak straight from the freezer!