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DouglasBaldwin

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  1. Since I don't see it mentioned above, you can also use my egg calculator (http://www.chefsteps.com/activities/the-egg-calculator) to compute the cooking time at different bath temperatures for different yolk viscosities. It solves a differential equation to compute the yolk viscosity based on Vega's paper and my own, extensive, experiments and measurements.
  2. I'm giving a free American Chemistry Society (ACS) Webinar entitled Sous Vide Cooking and Chemistry on 9 May 2013 at 2 p.m. EST. Registration is limited, so sign up now if you want to participate! (Coincidentally, I'm missing my doctoral hooding ceremony to give my webinar. But I can go to commencement the next day, so my friends and family still get to watch me graduate.)
  3. From a food safety perspective, there is nothing wrong with cooking from frozen. In fact, many food scientists recommend cooking from frozen; for example, O. Peter Snyder --- a food scientist I respect a lot --- recommends cooking your holiday turkey in the oven from frozen at http://www.hi-tm.com/Documents2005/turkey-cook-frozen.pdf . (Something most people are aghast to hear.) Some believe that the is a noticeable difference in texture, when cooking sous vide, between thawed and frozen; but I'm skeptical about this. Perhaps someone on here will do a blind taste test to find out. Either way,
  4. Or, I could generate and post a new table . EggHeatingTimes80C.pdf
  5. Morkai: The most important part of the “cooling to 4.4°C/40°F within 11 hours” is the initial cooling from 52.3°C/126.1°F to 21°C/70°F (say, within about 2 hours). The lower the temperature, the longer it can safely be held there; cf. Table A-2 in (FDA, 2011). Edit: Linked to wrong edition.
  6. Hi Morkai, Since there seems to be quite a bit of confusion, I thought perhaps that I might chime in. This is mostly a review of the food safety section of my guide and of my IJGFS article. Let's go through things step-by-step: You buy meat from a trusted source that doesn't have a strong smell, isn't slimy, and is before the best-by or use-by date. We hope that this will keep the number of microorganisms low, say less than 10/g of each of the Salmonella species, Listeria monocytogenes, etc. and less than 100/g of Clostridium perfringens (cf. Snyder 1995). We want this because it takes from 10
  7. I strongly recommend cooking directly after rapid aging and not refrigerating. Rapid aging without additional hurdles (as they're called in the food safety biz) is already pushing the boundary of what's considered safe. I'd suggest using an additional hurdle like an acidic marinade (with pH less than 4) as Pedro does and never using mechanically tenderized meat when rapidly aging.
  8. DouglasBaldwin : Is that really 45 '°C' - so not aging as people would think, but actually cooking at a low temperature? Yes, I did mean 45 °C / 113 °F. When I think ‘cooking’ I think about proteins denaturing and foodborne pathogens being reduced to a safe level. In that sense, rapid aging is closer to traditional aging than cooking. Even at 45 °C / 113 °F, many of the enzymes that affect the muscle fibers are active and can significantly increase tenderness — just as they do in traditional aging.
  9. Hi. Earlier this week, someone emailed me asking me why I talk about collagenase increasing tenderness below 60 °C after about six hours but that Heston in “In Search for Perfection” ages his steak at 50 °C and McGee says that fiber weakening enzymes “denature, become inactive, coagulate” at about 55 °C. I thought some of you might have the same question, so I've pasted my answer below: There are a lot of different enzymes in meat. We're mainly interested in proteolytic enzymes that split proteins or peptides (which are chains of amino acids) and these enzymes are called proteases. Enzymes are
  10. I actually do have a recipe for braised oxtail on page 62 of my book; I recommend 175F/80C for 12–18 hours.
  11. Thank you Shalmanese for your quick response to Tatoosh's question. To add a little detail, let me quote the food safety section of my web guide:
  12. I just wanted to let you know that the first issue of the International Journal of Gastronomy and Food Science is finally out. It seems that all 10 articles (including my review article on sous vide cooking) are available for free download.
  13. It's normal for the liquid in the bag to look unappetizing, especially for the long, low-temperature recipes. If you drain the liquid into a microwave-safe bowl and microwave it until it boils, it'll look more like what you're used to; many then filter out the precipitated (sarcoplasmic) proteins and brown them in a pan (with some fat) (add some flour to the fat to make a roux,) and then add the filtered liquid to make a simple sauce. That said, this method doesn't make a lot of sauce and the protein you just cooked is likely to get too cold while you prepare it.
  14. Hello Elsie, Let me see if I can unpack some of the comments made in this thread for you. When cooking, some thing happen quickly and other things happen slowly. In traditional cooking, few recipes take advantage of these slow processes. Sous vide cooking makes controlling these slow processes practical. The slow processes, like the enzymatic break down of collagen, mostly increase tenderness. If what you want to cook is tender, such as fish, then you want to limit the slow processes by not keeping the food in the water bath for too long. So if you are cooking tender pork chops, then you'll
  15. It's very hard to accurately predict heating times in a dry oven because the surface heat transfer coefficient, h, is too low (say 15–30 W/m2-K). For example, let's look at a variety of h values and see how it changes the heating time of a 50 mm cylinder to 54°C in a 55°C medium: h HH:MM 10 07:10 15 04:57 20 03:58 25 03:24 30 02:59 40 02:32 50 02:15 65 02:00 80 01:50 100 01:42 150 01:32 200 01:27 250 01:24 300 01:22 400 01:20 500 01:18 650 01:17 800 01:16 1000 01:15 As for food safety, I just don't have enough data on how sterile the interior of intact muscle meat really is. Obviously there's
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