Sous Vide Machines (Immersion Circulators)
Sous vide machines are cheaper, sleeker, and smarter than ever before. Can we find one that brings this high-tech cooking technique into the mainstream?
How We Tested
Whether or not you’re familiar with sous vide, chances are you’ve eaten food prepared this way. In the past decade, this method of cooking food in a precisely controlled water bath has rippled its way from Michelin-starred restaurants such as Alinea in Chicago and Per Se in New York to chains including Chipotle, Panera, and Starbucks, and it's now making a splash in home kitchens.
Here’s how it works: A water bath is preheated to a precise temperature. The food is sealed in plastic (though not always; you can sous vide in glass jars, and eggs can be cooked right in their shells) and immersed in the bath so that it eventually reaches the same temperature as the water. And in the case of meat and fish, there is usually a quick searing step before serving. This differs from conventional stovetop and oven methods, in which the heat used is much higher than the serving temperature of the food, making it imperative to remove the food at just the right moment so it’s fully done but not overcooked.
But with sous vide there’s usually no risk of overcooking, making it a game-changing technique—especially for temperature-sensitive (and often expensive) foods such as fish or steak. Long, slow cooking breaks down collagen to render even tough cuts such as chuck or pork shoulder extremely tender. The low cooking temperature ensures meat remains juicy, never dry; and dialing in the precise temperature creates exceptional, consistent results that can’t be achieved with traditional methods. It also eases the daunting task of cooking for a holiday meal or dinner party, since large quantities of food can be prepped hours in advance and held at the perfect temperature until serving time.
Home models of sous vide machines now come in two styles: big heated boxes called water ovens and slim, stick-like devices known as immersion circulators, which attach to a pot or container and continuously heat the water. We’ve found in previous testings that we prefer immersion circulators, since they heat faster, store easily, and work with vessels of different sizes, ranging from a saucepan to a large cooler. Circulators started out as hulking, expensive lab instruments, but manufacturers now make smaller, sleeker models with features such as wifi and Bluetooth connectivity, which are marketed to home cooks.
Though sous vide technology is rapidly evolving, we decided to take a look at all the major immersion circulators on the market right now. We evaluated seven models marketed for home use, with prices ranging from $129.99 to $274.95. Three of the models were wifi-enabled, with accompanying mobile apps. We tried the circulators in a variety of different-size containers and cooked foods to a range of temperatures, testing with eggs, salmon, flank steak, pork loin, and beef short ribs.
How Much Does Temperature Accuracy Matter?
We tracked the temperature of each bath throughout testing, timing how long the water took to come up to temperature and to recover after we added cold food and how accurately the circulators held their target temperatures. (All the models we tested can operate in Celsius and Fahrenheit. Though we tried the machines on both settings, temperatures are reported in Fahrenheit for the purposes of this story.) In addition to monitoring the temperature of the water while cooking food, we measured accuracy using lab-calibrated temperature tracking software to evaluate the circulators while they heated an empty 6-quart water bath for 3 hours, first at 149 degrees (the temperature at which, when cooked for 1 hour, eggs are soft-cooked, with just-set whites and runny yolks) and later at 190 degrees, the highest temperature some circulators can reach.
Most of the circulators fluctuated an average of 1 to 2 degrees from the target temperature over 3 hours, particularly when we set them to 190 degrees. The most accurate circulator, however, stayed within 0.2 degrees of the target at both temperatures. All the machines were able to recover quickly when we added food, usually reaching the target temperature after just 2 or 3 minutes.
Temperature accuracy didn’t have an impact on meat or fish; every model we tested produced tender and flavorful salmon, pork, and steak. Accuracy issues were noticeable, however, when we cooked eggs, which are very time- and temperature-sensitive. Circulators that fluctuated more than 1 degree from the target temperature often made over- or undercooked eggs. With eggs, we saw more consistent results with extremely temperature-stable circulators.
Ease of Use Is Paramount
While some circulators whirred to life with one touch, others required a confusing sequence of button-pushing to get started. A few wouldn’t run unless we set their timer function beforehand—a slightly bothersome extra step since one of the selling points of sous vide is that time isn’t as crucial. However, one model lacked an onboard timer, which was frustrating on occasions when we wanted to track the time, such as when cooking eggs. Some models beeped unnecessarily throughout cooking, and we had to repeatedly consult the manual to stop the noise. Others gurgled and churned rapidly, tossing eggs around and jostling delicate salmon fillets. We preferred circulators that were simple, quiet, and user-friendly. Our favorite models sported gentle motors but still heated water quickly; had intuitive dials, buttons, and timer functions; and beeped only when the machine needed our attention.
The Best Immersion Circulators Are Small but Versatile
The size of the circulator also factored in to how easy it was to use. The two circulators that weighed more than 4 pounds quickly heated a 6-quart bath to 190 degrees in under 15 minutes, but they took up so much room in the water bath that there was hardly any space to add food. We could fit only two or three steaks before the bags began to push up against each other, which prevented circulation and produced visibly undercooked spots on the food. Despite their power, these machines were too big to work with 4-quart saucepans or 7¼-quart Dutch ovens—the largest pots most home cooks keep in the kitchen. Smaller circulators were more versatile, easily attaching to whichever pot we tried them on; they were also slim enough to stow away in a kitchen drawer when we were done. We particularly liked the two lightest circulators, which weighed 2½ pounds or less and had minimal footprints. Though they took an average of 5 additional minutes to heat the bath, these products left plenty of space to keep food separated and circulating freely.
Distance Between Minimum and Maximum Water Line Matters
While using an immersion circulator, you have to keep the water level between the minimum and maximum fill lines noted on the unit. The minimum line ensures that there’s enough water for the circulator to pull into its heating ports and circulate, while the maximum line keeps water away from the sensitive electronics at the top of the circulator. In general, the wider this range, the easier a circulator is to use.
Water in the bath evaporates as you cook, though the rate and amount vary depending on the temperature and cooking time. Evaporation can be stalled by covering the cooking container with plastic, but the issue is avoided altogether in machines with a large distance between minimum and maximum water lines. These products didn’t need their pots to be refilled, and we didn’t have to worry about them shutting off in the middle of cooking due to a low water level.
This often came into play during the quicker cooking projects. (Sous vide projects can range from minutes for quick-cooking foods such as eggs or fish to several days for tough cuts like pork belly or short ribs.) For convenience, we prefer to leave the bath uncovered for such projects, but this meant that circulators with a short distance between water lines (less than 3 inches) were beeping and flashing error messages after just a couple of hours of heating.
A larger range between water lines allowed us to cook uninterrupted and gave us more flexibility to use the circulators with vessels of different shapes and sizes. We were particularly impressed with one circulator that had a generous 6.5 inches between minimum and maximum water lines, so we never had to worry about evaporation.
Do You Need a Sous Vide Machine with Wi-fi?
The potential for water evaporation also clued us in to the benefit of a wifi-connected circulator. Three of the circulators we tested could be paired with a smartphone using Bluetooth or wifi and the given brand’s companion app. (A wifi connection lets you monitor the cooking from far away, while Bluetooth requires your phone or tablet to be within range of the circulator to work. All three connected circulators support both types of pairing, though we opted for wifi since the connection is more stable.) The apps allow you to turn the device on and off, set the temperature or cooking time, and browse suggested recipes.
We loved that wifi-connected circulators allowed us to check the temperature, water level, and timer from across town, especially for longer projects. The apps could notify us when water was running low and, if needed, we could adjust the temperature directly from our phone.
However, the apps weren’t as helpful for quicker-cooking foods such as fish and eggs. For these uses, we liked the ability to set the temperature and timer directly on the circulators, which was faster than starting up the app and pairing the device. Of the three wifi-connected circulators, two weren’t completely tied to their apps; they also allowed us to set time and temperature directly on the circulators.
What Makes the Best Sous Vide Machines—and Why
Though we liked the convenience of being able to set temperature and time directly on the machines, the product that most impressed us had no controls on it; it functioned completely through a smartphone app. The Joule ($199.00 for stainless steel model, $179.00 for all white polycarbonate model) was the smallest circulator in our lineup; however, it had enough power to heat a water bath almost as quickly as the largest circulators, and it was accurate within 0.2 degrees of our target temperature. Though we were initially skeptical of having to use a smartphone app all the time, we quickly realized that the absence of exposed electronics was a big boon to versatility. Without front-facing buttons or display screens taking up space, the Joule has an impressive 6.5-inch distance between minimum and maximum water lines, so we never had to worry about evaporation. Plus, it was the only circulator that could tolerate accidentally being submerged in the water bath (the machine turns itself off if it tips over). It also has a magnetic bottom that allows it to stand in the center of metal pots, and it automatically downloads firmware updates that make the circulator even smarter as the technology continues to evolve. These small details combine to make sous vide cooking even more approachable for home cooks. If you are apprehensive about having to use a smartphone to sous vide, we also like the Anova Precision Cooker WI-FI ($199.00), which can be operated with or without a smartphone; it was fast and sleek and produced great results when cooking.
We tested seven immersion circulators priced from $129.99 to $274.95. We used each to prepare eggs, salmon, flank steak, pork loin, and beef short ribs. We evaluated accuracy and speed by tracking the temperature as each machine heated and maintained a water bath at 149 degrees and 190 degrees over 3 hours. Weight, height, footprint, and distance between minimum and maximum water lines were all measured in-house. All products were purchased online and appear below in order of preference.
ACCURACY: We tracked how well the circulators maintained a water bath at both moderate heat (149 degrees) and high heat (190 degrees). Top points were awarded to circulators that kept the bath within 0.2 degrees of the target temperature over the course of 3 hours.
SPEED: We timed how long it took each product to heat a 6-quart water bath from room temperature to 190 degrees. Full stars went to those that achieved this in 20 minutes or less.
COOKING: A team of editors evaluated the cooked food straight from the water bath. Points were awarded for food that was evenly cooked and, in the case of meat, juicy and tender. Machines lost points if they jostled and tore delicate fillets, cracked eggs, or left cold spots on the food.
EASE OF USE: Testers awarded full points to circulators that had intuitive controls, easy-to-set timers, clear displays, and meaningful alerts and alarms. We also evaluated the functionality of wifi pairing (if applicable) and the usefulness of companion apps.
VERSATILITY: We tried the circulators on 4-quart saucepans, 7¼-quart Dutch ovens, 8-quart plastic containers, and 9½-gallon coolers. Our favorite circulators secured easily to all these vessels. We also preferred circulators with at least 3.5 inches between minimum and maximum water lines, which allowed us to cook food for more than 72 hours without interruption. Bonus points went to circulators that alerted us when the water level was getting low.