How We Test Ovens
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Whether you’re finally replacing an old range or have always wanted to add a wall oven while renovating your kitchen, Reviewed has your back.
Not only do we perform repeatable, lab-based tests on ovens, ranges, and cooktops, but we also do real-world evaluations. That means we can tell you which products will perform the best, will give you the most bang for your buck, or have the sleekest looks. For more information on how we test ovens, ranges, and cooktops, read on.
Because the primary purpose of a range, cooktop, or oven is to heat up and prepare food, we collect data from a number of cooking and baking tests. However, we also want to tell our readers how a product deals with more mundane, non-cooking tasks. For that reason, we’ve also incorporated a few tests that do not include food.
Burner Maximum/Minimum Temperature (Ranges & Cooktops)
For products with burners, we measure the maximum and minimum temperature of each burner. Once the burner is set to its minimum or maximum setting, we place circular metal disks with a thickness of 0.25 inches, with varying disk sizes to match the different widths of the burner surfaces, on top of the burner. (We use metal disks instead of pots and pans because they can be machined for perfect smoothness.)
These disks are connected to temperature gauges. At the end of five minutes, we measure the temperature of each burner. Knowledge of the maximum and minimum temperatures of a burner can help consumers to identify which burners are ideal for simmering soup, and which burner can get hot enough to properly sear a steak.
A range or cooktop with multiple burners that can reach very high and/or very low temperatures will score well. If burners cannot reach very high or low temperatures—or if only one burner can do each task—scores will be lower.
Water Boil (Ranges & Cooktops)
One of the most common tasks for a range or cooktop is to boil a pot of water. For each burner, we take an appropriately sized pot, and fill it up halfway with distilled water. Then, we position a thermocouple horizontally in the middle of the pot, and vertically in the middle of the water column. We monitor the thermocouple and record the time it takes for the temperature of the water to reach 200°F.
If the water hasn’t reached 200°F at 35 minutes, then we stop the test. Because the water volume is different for varying burner sizes, we score the water boil test on the rate of water boiling: Faster water boiling will result in higher scores, while slower water boiling will result in lower scores.
Preheating (Ranges & Ovens)
Using a stopwatch, we measure how long it takes for the oven to achieve a preheating temperature of 350°F. We stop the clock when the oven’s preheat indicator goes off, whether it is a light or a tone.
Because no one wants to wait around forever, shorter preheating times result in higher scores, while longer preheating times result in lower scores.
At the end of the day, most people want to know how an oven, range, or cooktop is going to deal with food products. Accordingly, a considerable part of our objective tests show how well these products cook or bake your favorite foods.
Cookies (Ranges & Ovens)
One happy side effect of testing ovens is that there are always extra cookies lying around. In addition to being delicious, cookies double as a cooking/baking proxy for other thin food items, such as brownies or vegetables.
Those cookies started as twelve chunks of Pillsbury ready-to-bake sugar cookie dough, which we place on a dark, ungreased cookie sheet in a grid formation. After preheating the oven to 350°F for 15 minutes (following the directions indicated on the Pillsbury packaging), we place the cookie sheet in the oven on the middle rack for another 15 minutes. We remove the cookies from the oven, and allow them to cool for 2 minutes.
We repeat the process if there’s a second oven, or if the range or oven comes with a convection option. Because convection is commonly used to bake or cook multiple food items simultaneously, we use two cookie sheets: one sheet on a rack just below the center rack, and one sheet on a rack just above the center rack. We choose a multi-rack convection option if it is available, or standard convection bake if it is not.
To determine if the cookies are burnt or underdone, we use a spectrophotometer – an instrument that measures the color of something. We take readings from the tops and bottoms of all 12 cookies.
By comparing the color data between the cookies on the baking sheet, we draw inferences about how evenly the sheet of cookies was baked. By comparing the color data from the top and the bottom of an individual cookie, we have data that speaks to the baking consistency within a single cookie. We also check the cookies with our own eyes to make sure there are no blatant cooking issues lying outside our spectrophotometer’s test area—but we’ll explain a bit more about that later.
For the convection cookies, we still compare cookies to one another within a cookie sheet, but we also compare the color data of cookies in the same position on the two different sheets. Because convection is generally a more efficient way of cooking or baking something, it is important that the multiple food items on different racks be cooked or baked to the same degree.
For all of our cookie tests, the more similar the color data between cookies and within a single cookie, the higher the score will be. If the product has a second oven and/or convection capabilities, then the cookie scores for those tests and the main oven test are weighted and combined to arrive at a final score. This way, products with just a single, conventional oven are not penalized for their lack of a second oven or convection capabilities.
Cake (Range & Oven)
In addition to cookies, we use cakes to draw conclusions about an oven’s cooking and baking abilities with respect to larger, thicker food items such as casseroles or calzones.
Using Betty Crocker Super Moist White cake mix, we follow the cake batter assembly (using distilled water, egg whites, and vegetable oil) and mixing instructions on the back of the box for each cake. We use no-stick spray on the bottom of two dark 9” cake pans. The batter is distributed evenly between the two cake pans, and each pan is dropped three times to remove any bubbles.
As with our cookie test, we follow the recipe—preheating the oven at 350°F for 15 minutes. Inside the oven, we adjust the racks so that the two cakes can sit side by side on a middle rack, and bake for 30 minutes.
Once the cakes are removed from the oven, we immediately measure the cake heights at the cake center, and at 12, 3, 6, and 9 o’clock on the cake. Color data is taken at those same locations on the top and bottom of both cakes. If the product has a second oven and/or convection capabilities, then additional cake tests, identical to the one discussed above, are performed.
In this test, we compare the cake color data from one point to the other points on the same cake top or bottom, as well as between the two cake tops or bottoms. The more uniform the color measurements are on a single cake top or bottom (internal cooking consistency) and between the two cake tops or bottoms (baking evenness), the higher the score will be.
Again, as with cookies, if the product has a second oven and/or convection capabilities, then the cake scores for those tests and the main oven test are weighted and combined to arrive at a final score. This way, products with just a single oven are not penalized for not having a second oven or convection capabilities.
Pork (Range & Oven)
To understand how each product cooks meat products, we also use fresh, never-frozen pork loins for our objective testing. While we recognize that all natural products have variations that can affect test results, pork is exceptionally uniform.
Before testing, each pork loin is weighed, then placed on a rack in a roasting pan. A temperature probe is placed in the exact horizontal and vertical middle of the pork loin. After preheating the oven to 325°F, the pork is placed on the middle rack, and cooks until the internal temperature probe reads 160°F, which is the minimum safe temperature for cooking most meat products.
We then remove the pork loin, let it sit for 10 minutes, and re-weigh it to determine how much fluid loss has occurred. Then, the pork is cut into thirds so we can take color data from the center of each of the four cut surfaces. By comparing this color data, we can quantify how evenly the interior of the pork is cooked. An identical test is conducted if the oven has convection capabilities, using the Convection Roast option if available or the standard convection mode if not.
The more consistent the color data between the cut pork surfaces, the more consistently the pork has been cooked, and the higher the score is.
Toast (Ranges & Ovens)
Broilers are known for their rapid and even cooking, particularly when it comes to fish recipes. Because even cooking is vital to an effective broil, we use toast as a "heat map" to measure the heat distribution throughout the broiler.
After the broiler is preheated on the high setting for 5 minutes, we put 6 pieces of white bread in a broiler pan. We place the pan on the rack recommended by the oven’s use and care manual, and broil it for 3 minutes. Then, we remove the toast and collect color data from the center and four other specific places on each piece of toast.
Color data from each slice of toast is compared to the color data from other slices. The more similar the color data, the more evenly the pieces of bread were toasted, and the higher the score.
Cornbread (Ranges & Cooktops)
In order to find any hot or cold spots on a cooktop or rangetop’s burners, we include cornbread in our objective tests. Cornbread may seem like an unusual medium for testing a burner, but it is uniform and thick enough that it acts as a heat map—burning wherever there’s a high concentration of heat.
After preparing two or three boxes (depending on the size of the burner) of Jiffy brand cornbread batter, we grease the appropriately sized Lodge brand cast iron fry pan by applying 2 teaspoons of vegetable oil to the bottom of pan.
We pour the batter into the pan, and then suspend a network of temperature probes in the cornbread mix half an inch above the bottom of the pan. We set the most powerful burner to medium, and place the pan on the burner for 15 minutes. Temperatures are recorded for the entire 15 minutes.
The temperature values across the temperature probes at 10 minutes of cooking time give us an accurate representation of the heat distribution across the bottom of the pot. This test emphasizes the importance of cooking evenness on a cooktop or rangetop. The more similar the temperature values are across the entire pan of cornbread, the higher the score.
Objective Test Scoring
All of those tests make up the final product score, depending on the type of cooking product. For example, we assess cooktops with the maximum temperature, minimum temperature, water boil, and cornbread tests, but obviously don’t test for convection baking. We assess wall ovens with the preheating, cookie, cake, pork, and toast tests, and ranges are subjected to all 9 tests.
Because it can be tough to convey to readers how evenly baked a tray of cookies is based solely on color data, our reviewers also look at pictures of the tops and bottoms of each tray of test cookies, and assign a cookie evenness score on a scale from 1-4, where the score increases with the baking evenness of the tray of cookies. Depending on the cookie score from the color data, this cookie evenness score can enhance, maintain, or diminish the final cookie score.
In order to give our readers a well-rounded review of each product, we also score aspects of the oven/range/cooktop that are more experiential; here, our expert testers can subjectively compare one product to another.
Some scores are based solely on product’s specifications, including whether an oven has a self-clean function, or where the broiler is located. Others are more personal—like the quality of the preheat notification noise, or how stiff the oven door is. We very clearly define the different possible scores so that our scores are consistent from product to product and reviewer to reviewer.
In the end, we combine our rigorous objective testing with our descriptive subjective scores to arrive at a final score for each product.
Want to stay up to date on our reviews of the latest cooking products? Check out our list of range, cooktop, and oven reviews. For a constantly-updated list of our favorite products, check out some of our Best Right Now articles, like the Best Gas & Electric Ranges Under $800, Best Ranges, Best Wall Ovens, and Best Electric and Induction Cooktops.