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Everything posted by nathanm

  1. Very cool! You're clearly a maestro of bacon constructions!!
  2. That is a REALLY good point - SV does not rely on size effects, so you can test drive a small portion and it will work well. Indeed that is how we test things for the book - we do multiple pieces and then cook them for various times. When we like a time-temp combintaion we do a larger sample to be sure.
  3. This all depends on the final texture you want. We do pork shoulder for up to 48 hours at 60C. You get different texture at 24, 48 and 72 hours. We also like it at 65C for 36 hours, or pressure cooked for one hour. Each is very different result. I think you will find that the fatty portions are not quite tender enough if you do only 12 hours. Given your description I would guess 24 to 48 hours at 60C is your best bet.
  4. There are 5 hardcover volumes, plus the spiral bound kitchen manual (about 350 pages) which is printed on waterproof paper. So there are six volumes. That hasn't changed for the last 3 months, but about 3 months ago we had to split one of the hardcover volumes - it got too big. When you get too many pages in one volume, you get potential binding issues (the binding doesn't last as long, spine can crack. Also given the large format of the book it gets too heavy to be convienent for people. So yes, we went from 5 to 6 volumes, although not recently. Nevetheless, the Amazon page had originally been written for the earlier 5 volume set. Also, there is some lingering confusion between the fact that the 5 hardcover volumes are in one set, and then there is kitchen manual which we consider to be volume 6.
  5. Some news about the cookbook. We have had to delay publication by a couple months due to a number of factors. The new date is in March but we expect that the book may be available a bit before then. Also, the current issue of Food Arts magazine (subscribers should be getting it now) has a big article on the book.
  6. There is a big article on my cookbook in the issue of Food Arts that just came out. Also, the publication of the book has been delayed.
  7. As Pedro says, the key is insulation. Most water baths have very low wattage - 1000 to 1800 - which is about like a toaster. A typical home oven is 3500 to 7500 watts. So a water bath is quite weak. Depending on the insulation of the pot/water container there will be some watts lost. This could be large or small, depends on the level of insulation. The more insulation, the more water you can put in your bath. THe more water there is, the lower the temperature drop when you put food in which is good. Unless you put proportionately more food in! If the ratio of water to cold food you plunk in the bath is too extreme (i.e. too little water for the food) then you get a big temperature drop and it will take a while (perhaps too long) for the temperature to recover. I find that 7 liters is about the smallest bath that makes sense, and frankly 20 liters is much better. But no matter what the size, don't jam it too full.
  8. Sounds like fun, but my day job may get in the way! An even better idea would be to take the team and go across the country EATING great BBQ than cooking it. I bet we'd learn something, and it would be a change of pace from writing the book. However, all of that is indefinite future, right now our focus is on proofreading the galleys and telling the world about the book. This weekend I speak at a conference of food bloggers, and it will be interesting to see what they think.
  9. I do corn on the cob for 30 minutes at 60C/140F. This takes the raw taste away, but the kernels are still fairly crisp. It comes out very sweet. I usually cut the kernels them off the cob and serve them separatly, but you could serve them on the cob also.
  10. Any thoughts? There are several misconceptions in this text passage. Feel free to pass this along. Meat is mostly water! There was a classic Star Trek epiosode where an alien species refers to humans as "ugly bags of mostly water" and that pretty much sums up what any animal is (well, the ugly part can be debated). So no matter whether you inject or brine or just use meat as-is, there is plenty of water in the meat to evaporate. In the case of brisket it is about 71% water. The method of heating the meat does not matter, the same effect occurs for both radiative and convective heating. Now, as it so happens, radiant heating plays essentially no role in most barbeque, because radiant heating is only important when there is a high temperature source. Most barbeque is smoked with an air temperature (dry bulb) of 90C/194F to 110C/230F. At those tempertaures radiant heating is insignificant. Most barbeque rigs / smokers have the fire baffled so the meat does not directly recieve IR radiation from it. South American asado (from Chile or Argentina especially) does use radiant heat, but that is a very different method. However, even if there was radiant heating, it wouldn't matter. The point about wet bulb temperature is that evaporating water takes energy, so a wet surface that is evaporating will be cooler than a dry surface. It doesn't matter how you heat it, if the surface is wet, then it will be cooler than a dry surface if water can evaporate. When he says that wet bulb / dry bulb is about gas, I think there is some confusion. Wet bulb temperature is the temperature of a wet surface which is cooled by evaporation. It is a surface temperature. The air temperature is the dry bulb temperature. The reason that "gas" (i.e. air) is involved is that in order for the water to evaporate it must go into the air. If the air is already "full" of water (meaning that relative humidity is 100%) then evaporation can't occur. Anybody who sweats knows this - sweating is done to take advantage of evaporative cooling. The reason that we feel more uncomfortable in high humidity is that our sweating doesn't work as well. I am not sure that he understands that the temperature tests I did were not in a water bath. I took a vacuum sealed brisket and cooked it next to an uncovered brisket, but they were in the same oven. The sous vide bag simply stopped the evaporation. There is a TINY effect due to collagen, but it is so tiny that it does not show up unless you use a differential scanning calorimeter. If there was a large collagen effect, then we would see it in the temperature profile for the sealed brisket with no evaporation. But we don't. The test I did was in a convection oven, but a "free draft wood smoker" will not change anything. Water still evaporates! The existence of some smoke in the air won't stop water from evaporating. The smoke build up on the surface of the brisket may hinder evaporation slightly. The free draft part means that the smoker would, if anything, have a lower humidity than in the convection oven because the convection oven recirculates air to some degree while the smoker may, or may not depending on how open the dampers are. The amout of draft in the smoker, the way air circulates, how full the smoker is, the dry bulb temperature in the smoker, the relative humidity of the air outside the smoker will all make small differences. That is why different people report a "stall" of different temperatures and durations. The humidity outside the smoker has some effect, but only a small effect. The hotter air is, the more water it will hold. If you take air and heat it up to 90C/194F to 110C/230F, it will be very low relative humidity, no matter how moist the air outside is. Finally, he can find no reference supporting what I am saying here because, as far as I know, nobody has explained the BBQ "stall" this way before. It is a new explanation. I suspect that some food scientist somewhere may well have figured this out, but I am not aware of any. But that doesn't mean it is wrong - it just means it is new. The paper he quotes from Journal of Food Science supports ALL of what I am saying, by the way. It is a good early article on the topic of roasting meat. It confirms that there is substantial evaporative losses, and it confirms that the meat cooks with the surface at the wet bulb temperature.
  11. OF COURSE we cover Pacojets. I had the 2nd Pacojet in the United States, back in 1995, and have used it ever since. We have a whole chapter on combi ovens. I did start a combi-oven thread many years ago, around when I started this thread. There were no takers...
  12. The temperature stability and accuracy are mostly at or above 60C/140F. Below that it is nowhere near as accurate. Above there is it good, but not 1C. It is true that a big combi oven is expensive. One of the principles that we have with the book is that we don't "dumb down" content. So we have a bunch of material on combi ovens. We also tell you how do do things with home ovens. So while a Rational 61SCC is not for everybody, I think that it is important to support it with information. Electrolux makes a countertop professional grade combi oven that is $1900, so that is much more affordable. Several home oven manufacturers like Miele and Gaggenau are now making home combi ovens. So while a Rational 61SCC is not a home oven for most people, there are other alternatives.
  13. I have two of those ovens at home, and one in the cooking lab for the book. We have a whole chapter on them in the book. Yes you can use them for SV. They are not perfect for doing low temp sous vide (i.e. fish at 45C/133F), but are very useful for many other things.
  14. Here is the graph showing BBQ stall is due to wet-bulb temperature effects (humidity). Chris Young, one of my co-authors on the Modernist Cuisine book ran these experiments last night and this morning. We took one brisket, cut it in two. One was sous vide cooked, the other was not covered. Both were put on a wire rack in a Rational combi-oven in convection mode at 90C/194F, with a temperature sensor in the center (core). The wet-bulb temperature comes from an home-made wet bulb sensor (details of the sensor, and this whole topic are given in my upcoming book). Dry bulb temperature is from a sensor in the oven. You will notice that the sous vide sample actually is higher than the oven temperature. How can that be? The reason is that the oven temperature varies at various places in the oven by a few degrees. The sous vide brisket makes a smooth transition from its initial temperature up to 90C/194F, reaching that point in about 10,000 seconds (2.78 hours). There is NO STALL in the sous vide sample. The glitch in the dry bulb and wet bulb temperatures near the start is caused by opening the oven to put the meat in. The wet bulb temperature starts out at about 60C/140F. The WB temp rises as evaporation from the meat makes the oven higher humidity. It reaches a peak of about 80C, then declines over time becaues the meat is drying out, and the oven is venting air and moisture. The non-bagged brisket (labeled traditional) has a stall between about 7500 seconds and 15000 seconds (between 2 hours and 4 hours after the start). Eventually the surface of the meat dries out, so that the the surface reaches dry bulb temperature - at that point the stall ends and the meat temperature rises again. I think this pretty conclusively shows why there is a stall. The actual temperature of the stall will depend on the humidity in the oven, and a couple other factors.
  15. Would you mind posting the graph? Thank you. We repeated it again last night, with the same result. I will post a graph when I get the time.
  16. Yes - a 100% humidity environment is what you have inside a sous vide bag, or in a covered pot, or in a combi-oven in steam mode or CVAP oven. In that case there is no evaporative cooling, and there is no stall.
  17. We did the stall experiment. We took a brisket, and cut it in half - one piece was sous vide vacuum packed, the other not. Both pieces were put in a combi-oven in convection mode at 90C/194F. We had temperature probes in the air, in the core, and at the surface of each one. The stall occurred for the un-bagged brisket. The surface temperature of the bagged and unbagged meat started to diverge at 72C/161F. Below that point the bagged one was slightly lower (due to insulation effect and slick surface of plastic), but they crossed over at 72C and from that point forward the bagged one was hotter (both surface and core). The flat part of the stall was at 78C/172F. The flatest part of the stall curve lasted about 2.5 hours, then gradually creeped upwards. The temperature of the un-bagged brisket was still lower than the bagged brisket after 5.5 hours. I think this conclusively shows that wet bulb temperature effects (i.e. oven humidity and drying) are the source of the "stall" in doing BBQ. Uncovered meat will stall due to evaporative cooling, which gradually goes away as the surface dries. This also points something out that I am not sure everybody knows - you can cook sous vide in a convection oven. The reason that we all use water baths is that most convection ovens have poor temperature control compared to a water bath. The heat transfer rate to the food is also much worse, because water is about 1000 times denser than air. However you can do it. In this case we did it because I wanted the two brisket pieces to be under the same temperature and heat transfer rate - the only difference was surface evaporation.
  18. Roughly how long does it take for the skin to get crispy when using this method? Depends a lot on how much weight you have on top, and what the weight is. I would estimate 30 minutes in a 180C/356F oven.
  19. That is exactly what is going on. To cook a chicken to a temp of 60C/140F, you need the wet bulb temperature in the oven to be that high. If there is 100% relative humidity then wet bulb temp = dry bulb temp. So you need to either introduce more humidity, or raise the dry bulb temperature.
  20. We are still planning what we do about the launch. We don't have plans for a conference at this point.
  21. Yes, wet mops matter. Having water in the smoker (as is a water smoker) matters. Having the smoker be full of meat raises humidity, so that matters. Humidity is the source of a lot of the variation that we see in cooking processes. Professional smokers used for meat processing control humidity for this reason. Combi ovens and CVAP ovens do too.
  22. Yes, you got it right. I am going to run a brisket today or tomorrow to get the definitive test.
  23. Here is more detail, replying to Pedro and slkinsey. Heat gets into food from the surface. If the surface is wet, it will be at the wet bulb temperature. This depends on two things - the food staying wet near the surface, and also the relative humidity in the air around the food. If the humidity is 100%, as it is inside a SV bag then wet bulb = dry bulb. If the food is underwater, then there is no air to worry about and the temperature is again the same. The surface is wet because there is water in the meat, but over time the surface layers dry out. This tends to raise the temperature until with a very dry crust on the meat very little evaporation will occur and the temperature will be at the dry bulb temperature. The reason this affects the interior temperature is that the interior can't be any hotter than the surface. So if the surface is stuck at say 74C, then the interior can't get any hotter. As the surface dries out, the surface temperature rises, and sometime later the core temperature will too. As Pedro points out this would not happen inside a SV bag (or in a combi oven or CVAP oven in low temperature steam mode.) Yes we have done the experiment (sort of) - we have recorded temperature in meat cooked SV or in combi for long intervals and we do not see a stall. I say sort of because if you really wanted to check this out you would need to take two identical pieces of meat (say brisket), treat them indentically (dry rub and so forth) and then cook on in a smoker. We haven't cooked a whole brisket side by side. We did smaller pieces of meat, and we didn't do perfect comparisons. So a skeptic could still. Most smokers / BBQs have no humidity control, and people don't know what wet bulb temperature is. We show in my book to rig up a wet bulb thermometer. We think that is how you should control your BBQ, and once you do that we think that reports of the "stall" will disappear. I have several smokers and we have wet bulb temperature in them and you don't see a stall. We have also done experiments using a convection oven, or a very fancy smoker, where you can show the wet bulb effect easily. Take a convection oven (or combi oven in convection mode), set the temperature to say 60C/140F and put meat in, it plateaus at the wet bulb temperature. Finally, if you put meat in a DSC you can see a bit of a stall due to the various chemical changes that are happening but it is NOT a single fixed plateau, nor is the total amount of heat big enough to cause the reported hours-long "stall" that BBQers see. Conversion of collagen into gelatin is complicated it does NOT occur at a single temperature - it is a reaction that occurs at an increasing rate over a range of temperatures, all the down to just above the animal's original body temperature. It does not occur "at" a certain temperature. Sorry but I can't resist saying that all of this is covered in depth in my upcoming cookbook.
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