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Achieving the Proper Temperature Insights into Gourmet Home Cooking Products, Techniques, and Burned Yams

by Eric Norman


I recently burned roasted yams. Luckily it was Thanksgiving, so nobody really cared because we needed to have yams. Plus they were still rather tasty. But it bothered me, and I tried to think of why. Perhaps because I added maple glaze and didn’t reduce the cooking time. Perhaps my oven is different than the oven used to develop the recipe. It is not uncommon for ovens to deviate by 50 degrees around their setting. Oven temperatures can also drift over time, slipping out of calibration. Accomplished chefs know this, but to the average home cook it is not second nature.

For home cooks, ovens and other traditional temperature-controlled methods of cooking meat-such as using thermometers and temperature sensors-have long been affordable. But products to use those methods may soon be joined on the consumer market by new products that allow home cooks to prepare meat using a unique slow-cooking French method that until recently has been prohibitively expensive for home cooks.

Sous Vide Cooking Method

Sous vide (pronounced: “sue veed”) is a cooking technique developed in the 1970s that has come to prominence in the U.S. in the last 10 years via influential chefs such as Thomas Keller. Nathan Myhrvold, author of the modern cooking bible Modernist Cuisine, declares that, “Sous vide is an amazing cooking technique; it lets you have total control over how done something is, and you get perfect results every time.”1 The equipment consists of a water bath, a vacuum sealer, and a tool for finishing the dish. Water is good for two reasons. First, it has a high thermal mass, which means it can hold a specific
temperature well because it takes a great amount of energy to change its temperature. Second, because thermal conductivity is high the water imparts heat into the foodstuff quickly. Compare this to your standard oven, which uses air as the heat transfer mechanism. Air transfers heat more slowly, and every time the oven is opened the heat drops which makes it far from precise.

Water does have one drawback: If you put food into sub-boiling water it’s called poaching, and that cooking method yields a specific flavor. In sous vide cooking, the foodstuff is placed into a plastic bag to prevent the water from leeching out flavor. And to make sure air doesn’t slow the heat transfer, the bag is vacuum-sealed. Hence the name sous vide, which in French means “under vacuum.”

Then finally, the method calls for the foodstuff to be finished or seared with high-heat. This can be done in a cast iron pan or, more extravagantly, sous vide enthusiasts prefer a blowtorch. In high heat cooking, like an outdoor grill, you throw the food on and the outside nicely browns while the inside slowly comes up to temperature. Here that process is separated into two steps. First the low temperature for the inside doneness, and another for the outside crust or seat.

New Affordable Sous Vide Products

The consumer space for sous vide is rather interesting. The first products were repurposed laboratory equipment. Water baths used to hold chemicals or biological samples at extremely precise temperatures began to make their way into kitchens. They were expensive, and the d├Ęcor did not match sleek, stainless, modern kitchens. Prices were $2,000-plus for the water bath alone. As of this writing, there are new consumer products being launched that bring prices down from the current high cost of sous vide lab equipment. Better looking and friendlier appliances are leveling out in cost at around $200.

PolyScience may be regarded as the leading company with a history of chemistry lab equipment. They worked closely with top chefs like Grant Achatz of Alinea to create a line of food equipment for restaurants. According to Forbesmagazine, in 2007 five percent of the company’s $20 million in sales were from cooking gadgets.2The original products were much more precise than required, and had box-shaped and inert steel design features. Such features were needed for the equipment’s original function of mixing chemicals together, and no one cared what they looked like. However, high-end kitchen equipment for the home tends to be stainless steel or sleek black glass, and must be easy to use. Hobbyists began playing around with the technology and creating products of their own, creating competition which helped drive down the price. Over the last few years, PolyScience has introduced new models, dropping the price from $1,100 to $300. The retail presence remains slim, with only high end kitchen specialty retailers carrying these products. Williams Sonoma carries PolyScience and Sur La Table carries the Sous Vide Supreme, but in both cases the products tend to be on the bottom shelf or in some back corner. New competitors are going straight to cooking enthusiasts with consumer oriented products.

These new players have been successful marketing their products to the masses via crowdfunding. Crowdfunding is a disruptive business innovation which reverses the traditional startup cycle. Traditionally, an entrepreneur raises money, develops the product, produces a first run-all costing great amounts of money-then launches to the public and attempts to negotiate retail shelf space while hoping that sales realities match projections. Today, through crowdfunding, inventors receive pre-orders and working capital if the public buys into their vision. A year ago, when the Polyscience was selling for $800, a husband and wife team launched Nomiku on Kickstarter and received 2,000 orders at $330 each. In the past few months, the blogger Seattle Food Geek had larger success, selling 4,000 units at $200 apiece. The price is now in a reasonable territory for cooking appliances. These were both very successful campaigns, but of course to achieve multi-million annual sales means consistently selling thousands of units a month. Because the technique remains new and complex, it remains to be seen whether it achieves mass adoption.

Temperature Reigns Supreme

Temperature affects the chemical reactions of cooking, and controlling this lets us get closer to the results we are trying to achieve. Even the United States Department of Agriculture, whose concern is mainly on safety, points to the supremacy of temperature. The new doneness guide, released in 2011, gives the proper internal temperatures for cooking beef. Medium rare is 145 degrees, medium is 160, and well done is 170.3 The guide even discusses how visuals are misleading. Undercooked beef can appear brown, and overcooked beef can appear pink (this discussion is focused on ground beef, but the same principles of oxidation and aging are applicable).4 The simplest way to cook to a specific temperature is to use a thermometer. Instant-read thermometers like the Thermapen are great, and there are now even leave-in Bluetooth thermometers like the iGrill.

Steam Ovens for Higher Volume

For cooking higher volumes of food, there are ovens called combiovens and CVap, which are essentially precise steam ovens that are often programmable. Starting at $3,000 for small sizes, they tend to require a dedicated water source and an industrial 240-volt outlet, which regulates to the commercial realm. The CVap oven was originally invented to keep KFC chicken crispy while holding for order (think advanced orange glow lamp or bain marie).5 Quickservice restaurants, the fastest growing segment of the restaurant industry, are helping to grow demand for this kind of product. Chains like Umami Burger use a more defined process to deliver quality hamburgers consistently. A cooking time and temperature is set in advance, followed by a quick sear when it is time to plate the meal. This keeps the quality more consistent than having multiple line chefs cook the entire dish from start to finish. For the traditional diner grilling a traditional hamburger, this was fine, but the new restaurants are pushing the limits of quality to feed the growing foodie population.

With the help of a new wave of cooking entrepreneurs, and financing methods such as crowdfunding, consumers are being presented with new ways to prepare a gourmet meal at home. The increasingly popular foodie movement presents a unique customer niche. New home appliances are driving out the need for extensive trial-anderror cooking in your own kitchen, and at increasingly lower price points. Thanksgiving enthusiasts of evenly cooked, juicy turkey, and perfectly roasted yams may soon have a consistent result each year.

Eric Norman (Rady MBA, 2012) is making it easier to create restaurant quality food at home. At Rady, he was elected by his peers as head of the student body. He lives in San Francisco.


  2. Andy Greenberg, Gadets for your Future Kitchen, 2/11/2008,
  4. food-safety-fact-sheets/meat-preparation/color-of-cooked-ground-beef-as-it-relatesto- doneness/ct_index