The idea behind the refrigeration is that you can put a piece of salmon, for example, in the Mellow in the morning, use the Mellow's app to schedule when you want that salmon to be ready, and go about your day without having to worry about your fish floating around in room-temperature water until you want to hit the "on button." (And speaking of buttons, there are none on the Mellow. You control everything through the app.)
This is all fine and dandy, but some sous vide fans might not see the necessity to cool your water before it's time to cook. The concept of sous vide is to get water at a stable temperature; you can begin to sous vide your salmon in the morning and any decent sous vide product will hold the set temperature for as long as you need it to without overcooking the salmon.
But we've seen in our test labs how the structure of a tough piece of meat like a flank steak can change when you sous vide it over a long period of time; it goes from tough and chewy to delicate and tender, which might not be the best for every food item. Mellow gets rid of that possibility. It will only cook your food for exactly as long as you want it to.
Mellow cooks up tasty, tender dishes
The Mellow is at its best when you follow the cooking recommendations of its accompanying app. Steak that I prepared according to the app's preset temperatures surpassed what I cooked on manual mode using the standard cook times and temperature settings I use for sous vide tests. Thick cuts of New York strip steak were melt-in-your-mouth tender and juicy, and were cooked consistently throughout the meat. I set the Mellow to cook the steak to medium, though it's version of this doneness was a smidge on the medium rare side.
The Mellow lived up to its assertion to maintain temperature accuracy of plus or minus 1 degree Fahrenheit. However, there were some discrepancies between the actual temperature of the water in the Mellow versus what the Mellow app told me through notifications. For example, I cooked a steak at 140 degrees Fahrenheit. I wanted it to cook right away, so the Mellow began to heat the water immediately. I eventually received a push notification that the water had reached my desired temperature, but our test lab's temperature probe and the Mellow app showed that the actual temperature was still half a degree below 140. A Mellow spokesperson said the company is "working to improve the accuracy at the steady state temperature," and the next software update should reflect improvements in that area. It's good that the company recognizes this, but it's a little disappointing to have to wait for more accuracy.
The Mellow's size also made me cue the sad trombone. The appliance is 15.8 by 6.7 by 12.5 inches, and its water container can hold 4.5 liters. This is great if you're short on space and don't need to cook a lot of food simultaneously. But the narrow structure will limit the cook who wants to sous vide for a crowd. For example, a large cut of flank steak wouldn't fit into one of the Mellow's bags, let alone the container.
I also had some beef with the Mellow app. It's not immediately clear what your current water temperature is unless you decide to start cooking. And there is very little by way of actual recipes within the app -- you need to already know how to season and prep your food before you put it in a bag. That's a shame when you consider other sous vide companies, such as Anova, fill their apps with cooking guides and recipe suggestions.
The Mellow has its faults. But at the end of the day, it's a device that's reliable in creating meals that are cooked just as you like them. This is an appliance for someone who knows a thing or two about sous vide -- but stand down if you're still not sure about water-bath cooking.