DouglasBaldwin

My book, Sous Vide for the Home Cook, has time and temperature charts on pages 22--31 for beef, pork, lamb, venison, eggs, chicken, turkey, duck, fish and shellfish, vegetables, fruits, and legumes. Thomas Keller's book also has a chart of temperatures and times. And, as Chris mentioned, the new index has temperatures and times. With any chart, mine included, there are implicit assumptions that you should be aware of. For my charts, I assumed the ingredients were purchased at a grocery store -- so my cooking times may be too long if you are cooking up 45-day-dry-aged prime-cut beef. Likewise, Keller's chart assume that you're cooking the very best ingredients money can buy and may not be the best time and temperature combination for supermarket beef. Finally, both our charts assume certain maximum dimensions for the food being cooked since size and shape have a huge impact on the cooking time. (I also include pasteurization tables based on thickness in the back of my book and in my web guide, see the link in my signature below.) So to make the most from the times and temperatures in the index, you'll want to read the posts they link to to see what their assumptions were.

I don't know any off the top of my head -- I wrote almost all my code in Mathematica. Probably the easiest language to program something like that up in would by Python using the free SciPy and NumPy packages. I'd do it myself, but I'm spending 60+ hours a week on my Ph.D. and just don't have the time. (I spent a week more than a year ago trying to code something up in Mathematica but my calculations didn't match my experimental data to my satisfaction.) If anyone is willing and able to code it up in Python, please feel free to email me and I'll share what I've done and the research papers and data I've collected on modeling the freezing and thawing meat.

Oooh! How I missed that is beyond me. I reviewed your guide earlier to come up with the range of 160 to 170 (effective pastuerization, esp. of the sketchy stuffing meets the time/temp requirements for tender dark meat). The way I read that chart is that it's the time to reach equilibrium temperature with the bath given a particular shape. Is there a similar chart (or, better, an equation) that models the specific case of frozen-to-long-cook, where the bath temperature is > pasteurization temperature? Stated another way, I'd like to model a system where for, a given shape with "forcing dimension" X, Starting Temperature Tstart and bath temp Tbath, the time to a given temperature of interest Tinst is calculated, including accounting for the heat required to make the phase change if Tstart<1C E (edited for clarity) The usual suggestion for cooking from frozen verse thawed is increase the time by half; in many cases, this works quite well. As for a formula for the time.... With some knowledge of Fourier series methods and Sturm–Liouville problems, you can fairly easily find a formal solution of the heat equation for a sphere, cylinder, or slab. Indeed, several students in the upper-division engineering math course I TAed last semester did it as part of their class project. Solving the heat equation from frozen is not as easy. From thawed is a linear problem while the from frozen is a nonlinear problem (since the thermal diffusivity is highly nonlinear near the freezing point); nonlinear problems are much harder to solve than linear problems; so most people approximate it as two linear problems with a moving boundary condition and it's referred to as the Stefan problem --- needless to say, all of this is way beyond the scope of this forum and is why Nathan and I give tables instead of formulas.

I link to a chart I made for heating spheres, cylinders, and slabs in this post.

Our family loves lamb and we frequently do boneless leg of lamb sous vide. I usually cook it for 24 hours at 130°F (55°C) and then blowtorch it (with my Iwatani butane blowtorch) until the surface is a nice mahogany brown. Coincidently, I served a boneless leg of lamb last night with the mint pesto recipe in my cookbook and everyone loved it.

Quick note: I assumed in my cookbook, since it's for home cooks, that everything was purchased at a grocery store; that is, I assumed the beef was choice and wet-aged about 2 weeks. If you are using a well aged (say 28 day) prime-grade rib roast, then you'll probably only want to bring it up to temperature. If you did get it at the supermarket, then I think you'll want to go the 8--12 hours to tenderize it some.

I did indeed pick worst-case pasteurization times for my recipes. (I did include pasteurization tables based on thickness on pages 256 to 258.) For the recipes, I tried to determine what the worst-case time would be for a given piece of meat constrained by weight; I was more explicit on steaks and usually give a thickness range to assure pasteurization. Being for home cooks, I implicitly assumed that they'd be buying their beef at the supermarket. When doing my testing for my book, I found supermarket rib-eyes to be fairly tough and so specified 6--8 hours in my cookbook. If you're buying well-aged, prime-grade rib-eye steaks, then 6--8 hours is going to be too long and you'll want to cut the cooking time down to 1--1.5 hours. I apologize for not responding sooner, but I usually don't check the "Cookbooks & References" board. If anyone has a urgent question, emailing me is your best bet.

I'm trying short ribs for the first time this week and am thinking about the anti-pathogen dunk -- but would it also work to give the short ribs a quick sear with a blowtorch prior to bagging? ...might want to do both unless you are incredibly thorough blowtorching the surface. Cooking Issues recommends searing meat before and after sv'ing, and I can certainly taste the difference. Below is a quote from an email I recently sent to one of my readers about this:

I'm afraid our applied math department server died over a week ago and I don't know when they'll be back up. I've now permanently moved my sous vide guide to http://www.douglasbaldwin.com/sous-vide.html. [i hate having to pay for server space, but I just don't trust my department's servers anymore and too many people count on my guide.] Please use this address in your future posts (and update your links up-thread if you're able).

I have a recipe for apples in my cookbook: 185F (85C) for 30--40 min. The exact time depends on the acidity of your apples --- high acid apples soften faster than low acid apples. For more details, you can always see my book --- though I only discuss fruits and vegetables briefly since I rarely cook them in sous vide in my own home.

ScottyBoy: In my original post on using a glucose solution to promote the Maillard reaction, I recommended a 4% glucose wash. While the concentration does make a small difference in the final taste, I usually just add a drop of light corn syrup to about a quarter cup water and stir until it's well mixed. If you're really interested, I can dig up the journal articles and give you references for further reading. Paul: I generally agree with the above comments. I'd suggest cutting a little meat off and testing 53C for a few hours and then searing it with a blowtorch (since pan-searing would overcook too much of a small piece of meat). But I'm a scientist and like to empirically verify my theories.

It's been quite awhile since Nathan or I got into the science of heat transfer in food on here. Since Nathan's recent posts on `stall' have a lot of science behind them, I'd like to unpack them a bit. I hope my expanded explanation from a slightly different perspective will aid your understanding. Heat transfer in food is wonderfully complicated! If it were simple, there wouldn't be several academic journals devoted to its study. First I'll discuss how Nathan and I model heat transfer in sous vide cooking. Then I'll discuss the more complicated problem of modeling heat transfer in dry ovens and smokers. [i won't discuss the mathematics because it's beyond the scope of this thread. I'll restrict my discussion to meat.] SOUS VIDE COOKING We can very accurately model the transfer of heat in sous vide cooking if we know: the thermal properties of the food, the food's shape and initial temperature, the surface heat transfer coefficient of the water bath (or convection steam oven), and the water bath's temperature. For example, Nathan emailed me some measurements he took while cooking a 80mm cylinder of beef and my mathematical model calculated the core temperature (without any fiddling with the parameters) to within +/-0.1F! Thermal Properties of Meat We model the temperature inside the meat using the heat equation. The only parameter in the heat equation is the thermal diffusivity of the meat.1 Between refrigerator temperatures and boiling, we usually assume that thermal diffusivity is constant even though it change slightly with temperature. The change in thermal diffusivity with temperature depends on the specific heat capacity of the meat. As Nathan mentioned, one way of measuring the change in specific heat capacity is with a differential scanning calorimeter (DSC).2 The specific heat capacity tells how the temperature changes with the addition of energy. Kemp et al. (2009) showed that the specific heat capacity of muscle fibers and sarcoplasmic proteins is essentially flat from 30C to 85C, connective tissue has a hump peaking around 60C, and fat is essentially flat over 50C. Therefore, the `stall' in smoking at around 74C isn't caused by chemical changes in collagen or the melting of the fat. There are huge change in thermal diffusivity of meat outside 0C to 100C. Melting/freezing takes a huge amount of energy: it takes about as much energy to heat beef from -20C to 0C as it does from 0C to 70C. It takes even more energy boil away the water in the meat, but we don't have to worry this when cooking sous vide so I'll discuss this later. Shape and Initial Temperature See my previous posts about shape and cooking times. In short, the shape of the food has a huge affect on the cooking time. Initial temperature, so long as the meat isn't frozen, doesn't really matter. Surface Heat Transfer Coefficient and Water Bath Temperature To be able to calculate the temperature inside the meat (using the heat equation),3 we need to know how the temperature changes on the surface of the meat. In sous vide cooking, we can very accurately compute this from the temperature of the water bath and something called the surface heat transfer coefficient. The water bath's temperature and how to control it has been discussed extensively previously in this thread, so I won't discuss it further. The surface heat transfer coefficient is an intrinsic property of the water bath or convection steam oven.4 It describes how efficiently the energy in the bath can be transferred to the meat. In water baths, it mainly depends on the natural or forced convection (or movement) of the water. [in convection steam ovens, it mainly depends on the condensation of water vapor on the food.] If you've been outside when it's cold, you've probably experienced this first-hand: when it's calm out, your body is able to heat a thin layer of air around you so it doesn't feel so cold out; when it's windy out, the wind is continually removing this warmed layer of air so it feels much colder out. It's the same idea when cooking food in a water bath: if there isn't any convection, then the cold food cools a thin layer of water around it and the surface temperature takes longer to reach the water bath's temperature; if the water is always moving, then this layer of cooler water next to the food is removed and the surface temperature reaches the water bath's temperature much faster. The surface heat transfer coefficient, h, is measured in W/m2-K. Once h is above a certain threshold, there is practically no difference in how quickly the core temperature increases. That is, once h is high enough, the limiting factor on how quickly the core temperature changes is the thermal properties of the meat. I've started doing empirical tests to measure h for all the water bath's we typically use. I've found that h is about 95 W/m2-K for my SVS and about 155 W/m2-K for my 2 year old PolyScience immersion circulator: both these h are above this threshold. In dry ovens (both convection and standard) and consumer smokers, h is below this threshold and small difference will cause large changes in the cooking time --- Nicolaï and Baerdemaeker (1996) reported that the h of dry convection ovens is about 14--30 W/m2-K. So different ovens and smokers will have significantly different cooking times. DRY OVENS AND SMOKERS While the meat at the surface still retains most its water, we can use the same heat equation and take the thermal diffusivity to be constant. The main differences are that h is much lower and how quickly the surface temperature increases is proportional to the difference between the wet-bulb temperature in the oven and the current surface temperature of the meat. (In the water bath, the surface temperatures rate of change was proportional to the water bath's temperature, which is always equal to the wet-bulb temperature, and the surface's current temperature.) As Nathan's explained, the wet-bulb temperature is cooler than the dry-bulb temperature in an oven when the relative humidity is less than 100% because of evaporative cooling. Evaporative cooling is so important because it takes a huge amount of energy to change the phase of water to water vapor --- it takes five times as much energy to evaporate a mass of water as it does to heat it from 0C to 100C! When the meat at the surface has desiccated (dried out), we can no longer assume that the thermal diffusivity is constant --- indeed, it changes dramatically. This makes it very difficult to calculate the core temperature of the meat and so is beyond the scope of this post. This is also when, as Nathan discussed, that the dry-bulb temperature in the oven or smoker becomes more important. Since this doesn't really apply to sous vide cooking, I'll leave it for a later discussion; if you're really interested in how we deal with this `moving boundary value problem' then either Nathan or I can direct you to the relevant literature or discuss it on a more relevant eGullet thread. Footnotes Thermal diffusivity is defined as the thermal conductivity divided by the specific heat capacity and the density. The very small sample size that must be used in DSC, usually less than 0.1 grams, makes getting a representative sample difficult. So most studies look at the meat's components --- myofibrillar proteins, sacroplasmic proteins, connective tissue, and fat --- separately. Previously, adiabatic calorimeter were used because they accept much larger sample sizes. The heat equation is very well behaved, if we know the temperature on the surface and the initial temperature, then there is always a unique solution. If the water bath is held at a fixed temperature, then the heat equation tells us that the interior of the meat will (eventually) go to that temperature. How the food is arranged can detrimentally affect the surface heat transfer coefficient:. Closely packed food cannot be heated as efficiently as adequately spaced food, which is why it's important to keep the food pouches well separated. References Robert Kemp, Nike North, and Shane Leath. Component heat capacities for lamb, beef and pork at elevated temperatures, Journal of Food Engineering (2009) 92, pp. 280--84.

Nathan, I certainly wasn't saying that your incredible search for your perfect recipes isn't important. I have no doubt that what you've discovered will help many people find their perfect recipes. I'm also sure that many people's perfect recipes will share many common ideas and techniques. Consider the skinless chicken breast: I prefer mine pasteurized at 140F (60C) and my mother prefers hers pasteurized at 145F (63C). Is one temperature really more `perfect' than the other? For me, one certainly is; for my mother, one is certainly is; but these temperatures are not the same and nothing either of us can say or do will convince the other that they're right. Indeed, neither temperature is `perfect' for everyone but either temperature might be `perfect' for someone. As another example, consider tea. I prefer a loose-leaf green tea with a light grassy flavor. I'm sure that's not everyone's favorite cup of tea. But that doesn't mean the techniques used to make my perfect cup of tea won't help you make your perfect cup of tea.

Nathan hit it on the nose. I prefer a confit-like texture for my poultry legs and thighs and that's reflected in my recipes. Likewise, I prefer my yolk to form a tender gel; if you prefer your yolk runny, then your `perfect egg' temperature is probably 146F. (Sadly I wasn't allowed to include any photographs in my book, otherwise I would've included the picture-temperature-egg-matrix from my web guide next to the `perfect' egg recipe.) My recipes just represent what me and my family prefer based on hundreds of experiments, the vast academic food science literature I've read, and constrained by the current best food safety practices. I always put quotes around `perfect' when talking about recipes because I don't believe there is a `perfect' duck breast recipe or `perfect' roast beef recipe. Different people like different things: so there is no one `perfect' recipe, but there are many recipes that are `perfect' for someone. [Moreover, your `perfect' recipe often has more to do with your previous experiences and memories than some absolute notion of optimization.] If you haven't watched it, you may like Malcolm Gladwell's very relevant TED talk on spaghetti sauce.

Yes indeedy. That's why I give an alternative method using a higher temperature (167°F/75°C) for a precise time that I calculate from egg circumference (based on empirical measurements I made) to set the white so it isn't watery.

As for eggs, I'll quote my cookbook: I may have the times from Table 1 of my book somewhere up thread, but I can't remember.

I have a recipe for turkey breasts in my guide along with pasteurization times. As a special treat for yourself, remove the skin and crisp it between parchment covered sheet pans in the oven until golden brown --- yum.

Thank you for your constructive criticism: I'll make sure the volume level is higher next time and that you can see what I'm doing. I'm generally a cheerful and outgoing guy, but I'm not used to being videotaped and it showed --- I'm sure the more I do, the more myself I'll be. Since I used my cousin's video equipment (who was visiting last week on vacation), I'll order a video camera and will plan to make a new video every week or two. [i still plan to do a major revision of my guide, but working in the office 60 hr/wk on my doctorate is keeping me from making much progress on it.] As for my book's availability, I'm afraid I don't have any control over it. I'll keep sending them emails voicing your complaints and hope they make it available to you soon. Thank you again for all your comments and support.

You might be interested in the two YouTube videos I made this week on sous vide cooking: Sous Vide Chuck Roast Sous Vide Chicken Breasts I've never made or posted a YouTube video before, so they're pretty rough. Do you think I should make more YouTube videos on sous vide cooking? If so, what topics/recipes do you think I should demonstrate?

Chris, Yes, it's the same. I probably should have put "not frozen" instead of "thawed"; but since I get my beef by the half, my mental image of beef is white-paper wrapped packages in our freezer with our name, the date, the cut, and the locker's name stamped on it. When you (chamber) vacuum seal your formed, not-frozen hamburger patties, I recommend using a weaker vacuum setting (say 90--95%); if the patties are frozen, then you can use the 99% vacuum setting. Depends on thickness of the burger or whatever, see Douglas Baldwins's table 5.8 Baldwin notes that this is for "thawed meat." Are the times identical for meat that's never been frozen?

I don't. It was on my to-do list, but I never got around to it. I do include vegetables and dried beans though.

adey73: Yes, that's what MartinH means. It really is very convenient to making custard ice cream bases sous vide. MartinH: Thank you for your very nice comments, I'm very glad to hear that you like my book.

Thank you for all your support and kind words; I really appreciate it. Paul: I asked my publisher and they don't have any immediate plans to do an electronic version. (Besides, while I love my Kindle, I find the paper version to be much more convenient than the Kindle version I made for myself; but that's just my experience.)

Hello, I just wanted to let everyone know that my cookbook, Sous Vide for the Home Cook, is finally out. At the moment, you can only get it through the SousVide Supreme site (for $24.95 plus shipping). It should be available on Amazon.com soon and Amazon.co.uk in about a month. I spent a lot of time on it and am very happy with how it turned out. It has 272 pages with over 200 recipes (plus a giant table with sous vide cooking times and temperatures for everything I could think of). I designed it for home cooks with straightforward recipes that don't call for any exotic ingredients or equipment (other than a temperature controlled water bath, of course ). Indeed, after I sent off my manuscript, my father (who hadn't cooked anything in decades) started cooking my recipes for my mother and they've all worked great for him. My recipes aren't designed to be tasty works of art like those of Mr. Keller or Mr. Blumenthal or Dr. Myhrvold: but I think they're delicious and hope you'll think so too. While the text is light on math and science, I used a lot of math and science in designing my recipes: I numerically solved the heat equation to compute the heating and pasteurization times; I used network theory and the volatile flavor compounds of the ingredients to design my sauce recipes; and I applied what I learned from the 350 or so academic food science journal articles I've read in the last two years. I look forward to hearing what you think of my cookbook once you've cooked a few of its recipes. As soon as I finish writing two chapters on sous vide and cook-chill processing for an academic text (intended for food scientists and industrial food processors), I'll get back to work on the next major revision of my (still and always) free web guide. (There's a lot of new material I want to add to my guide; but it'll take a while now that I'm back to working on my PhD thesis 60+ hr/wk .)

That's an excellent question. I got the corrected proofs of my book last week; so I hope that it'll be headed to the printers very soon. It came out to be 271 pages and has a little over 200 recipes (not including variations). I'll post here what the official publication date is as soon as they tell me what it is.