PedroG

Depends on thickness of the burger or whatever, see Douglas Baldwins's table 5.8

Hi Pete J, that's a very smart solution, it avoids the interference between my bent skewer and the lid of any pot. But I suggest to try to force the bags into a vertical or at least oblique position for better (natural or forced) circulation, so you might pin the bag to the fiberglass rod with clothes-pins and eventually weighing the other end of the bag down.

You can easily infuse fruits and vegetables with a clamp type machine using vacuum containers, not bags, see Instant rum pot and Infusing cucumbers, melons etc. With the weaker vacuum of clamp type machines compared to chamber machines, the fruits will not become as perfectly translucent as in Jean-François' experiments, but on releasing the vacuum, the surrounding liquid will be sucked into the fruits anyway giving them the desired flavor. When fruits are kept compressed in the bag for a prolonged period, they might lose their elasticity and on releasing the vacuum they might not aspirate as much liquid as on immediate release of the vacuum. Would one of you guys with a chamber machine (blackp? Douglas Baldwin? Jean-François?) do a comparison test? Infusing is VERY different from compressing fruits significantly. I know several professional chefs that have had the compressed watermelon (for instance) from French Laundry. And they have tried and tried with clamp-type vacuum packers to get it to work and all have said that the tiny amount of compression that you get with a FoodSaver (and similar device) is just not enough to get the radical compression that people can get with good chamber-type sealers. The texture changes quite radically with Keller's method. I have wondered if there is some kind of hand pump that can do it. The syringe trick (if I am understanding it right wouldn't work for compression. Infusion works by sucking the air out of the spaces and having the liquid replace it when atmospheric pressure returns. So, it requires a rigid-walled container. According to post 2049 and following the difference in compression force between 800mbar (clamp type machine) and 999mbar (chamber machine) would not make such a terrible difference. Has anyone confirmed NY_Amateur's experiences? With the syringe trick you could apply positive pressure much higher than the difference between atmospheric pressure and vacuum. Did anyone try that?

$24.95 / 272 pages = 9.2¢/page, printing an e-book at home will cost you more.

Hi Douglas, unfortunately the SVS site only ships to the USA and Canada, so we Europeans and Australians will have to wait for Amazon. Regards Pedro

The air that bubbled out of the intercellular air spaces will collect above the surface of the infusing liquid, and on release of the vacuum, there is only surrounding liquid, no air, to be sucked back into the intercellular spaces.

You can easily infuse fruits and vegetables with a clamp type machine using vacuum containers, not bags, see Instant rum pot and Infusing cucumbers, melons etc. With the weaker vacuum of clamp type machines compared to chamber machines, the fruits will not become as perfectly translucent as in Jean-François' experiments, but on releasing the vacuum, the surrounding liquid will be sucked into the fruits anyway giving them the desired flavor. When fruits are kept compressed in the bag for a prolonged period, they might lose their elasticity and on releasing the vacuum they might not aspirate as much liquid as on immediate release of the vacuum. Would one of you guys with a chamber machine (blackp? Douglas Baldwin? Jean-François?) do a comparison test?

Floating bags In my experience, bags have the most tendency to float in flat water (e.g. pan-in-the-oven-method), whereas in a pot with sufficient depth to allow the bag to stand vertically, there is less tendency to float. Suspending bags on a skewer helps even more to prevent floating: Bagging with marbles or glass cubes or the like forces submerging and vertical position: Alternatively, a table cloth weight may be attached to the bag (needs added depth in the pot): I suspected that in the FreshMealsMagic the fine air bubbles might decrease the density of the water sufficiently to make a Ziploc bag full of water sink down, but the opposite was the case, as the air bubbles adhered to the plastic bag and made it float: Bubbler off, bag plunging. Bubbler on, bag starts surfacing. Bubbler on, bag floating.

If you have a floating problem, see Weighing down with glass beads

Sous vide immersion circulator 449€ Unstirred sous vide water bath 450$ Sous vide immersion circulator including 18L container 300$ PID-controller 160$ plus immersion heater 35$ plus aquarium bubbler 11$ plus 28 quart cooler 26$ make an immersion circulator including well-insulated container for 232$ DIY Sous Vide Heating Immersion Circulator for About $75 needs extensive tinkering Water-pot / oven method 0$

See Harold McGee, On Food & Cooking, page 152: muscle fiber weakening enzymes are active up to 50°C, above they get inactivated. (Collagenase is active in the fifties, and gets inactivated towards 60°C). Aging beef can be done at room temperature for 24h (I used to do this, acidifying below pH 4 with marinade containing mustard to prevent bacterial growth), or you can do "turbo conditioning" at 49°C for one hour, but then you should avoid olive in the marinade, as it is said to give an off-flavor. In my experience, the effect of turbo-conditioning is rather marginal, but I did not make a double-blind comparison. @ Alan, will you do the comparison?

I try to clarify the 4h-6h-rule: If you go for ≥ 54.4°C and pasteurizing conditions, you have to heat your food from 4°C to 54.4°C core temperature within 6 hours. If you do not go for pasteurizing conditions, e.g. when cooking fish to 43.5°C, the food must not be more than 4 hours between 5°C and 54.4°C. That’s why the heating time tables do not go beyond 55mm thickness for temperatures < 54.4°C (4-hr-rule) and not beyond 70mm tickness for temperatures > 54.4°C (6-hr-rule). Alan, I hope this answers your question. Pedro

I had a plastic pump spray which worked like a charm for years until it ruptured when I filled it too high and pumped it too much. Now I have a Cuisipro Stainless-Steel Spray Pump Non-Aerosol Mister which after a few month became a piddler like Pierogi described. I filled it with 70% alcohol and sprayed until the nozzle was clean, now it works again as it should.

In long-time cooking (48 hours typically) a few hours more or less will not matter, so just put as many bags as necessary in the bath 48 hours before the party (cook-and-hold), and when the party is over and you have some bags left, rapidly chill them in ice-water for later use. Alternatively, you may cook-chill a few days earlier and reheat before the party (heating time according to Douglas Baldwin's tables), but beware, dropping many bags in the water bath may cause a significant temperature drop, so you have to consider the recovery time from the temperature drop. If you need a very large water bath for a big party, see FMM in bath tub Regards Pedro

mis, I had the same brisket-flop last Xmas (Frank Hsu quoted me in this blog ), and I also suspect I had a cut of "brisket" that was not beef breast but some other cut containing more elastin than collagen (which according to Douglas Baldwin occurs in some muscles in the rump). Since then I always look for a cut which has obviously been cut from the ribs, i.e. I can see the intercostal muscles. Apart from this flop, my briskets 55°C/48h always were fork-tender and succulent. I have no experience with short ribs. My other preferred cuts are "brisket" from veal 55°C/24h, veal shoulder 55°C/5h (16h was too much, falling apart), beef shoulder 55°C/50h, which all came out even more tender than brisket. Here is an explanation on gelatinizing of collagen from Douglas Baldwin (personal communication 26.12.2009): Our experiences with tenderizing tough meat show that thermal breakdown of collagen, contrary to Harold McGee's On Food & Cooking (page 152) and to http://www.britannica.com/EBchecked/topic/371756/meat-processing/50359/Structural-changes , does occur at temperatures well below 70°C, but it takes much more time. Regards Pedro

Hi Edward, I agree with you. Any ground meat must be cooked to pasteurizing conditions, and the same is true for any meat that has been jaccarded, larded, injected or otherwise surface contaminants have been transported into the meat. I took it for granted that meat cooked sous vide will be seared before or after cooking. When post-searing, an additional safety measure may be dunking the bag in boiling water for a few seconds after sealing. Regards Pedro

Ben, I think you are on the safe side, but leaving your protein in the intact bag for rapid chilling in ice-water and storing in the refrigerator would make it even safer.

Hi Merridith, I reply to your PM concerning pasteurizing in the forum, as food safety aspects in sous vide cooking are even more important than in traditional cooking and should be of general interest. Poultry: See post #3535 Beware microbes in poultry. Pasteurizing poultry is mandatory (see Food Safety Hazards And Controls For The Home Food Preparer page 2). Texture may be better with shorter pasteurizing times at higher temperatures, so e.g. for a 25mm thick (see Measuring thickness ) chicken breast 69 minutes at 60.5°C may be preferable to 138 minutes at 57.5°C (see table 4.7 in Douglas Baldwin's Practical Guide to Sous Vide Cooking ). Meat: Pasteurizing is required only for immune compromised persons and is only suggested for everyone else. Tender meat: with cooking times up to 4 hours you are free to select the core temperature suiting your taste. My personal preference is 52°C for pork and veal, 53°C for beef and 55°C for lamb racks. Tough meat: long time (12-48h) cooking is required to gelatinize collagen, so 55°C is microbiologically safe (even if your SV bath should be off by 1°C), enzymatically (collagenase) adequate, and results in a medium-rare to medium aspect. Fish: As fish live in cold water, their (autolytic and other) enzymes as well as microorganisms living on them are adapted to work at 0-5°C. So storing fish in a household refrigerator will not prevent spoilage and self-digestion of fish. Eat fish before it eats itself! The freshest fish is frozen fish, and professional freezing (-35°C for 15 hours or -23°C for seven days, see Harold McGee, On Food & Cooking 2004, page 186f.) kills parasites like Anisakis worms, allowing you to cook fish rare to medium-rare (43-49°C) instead of pasteurizing at 60.5°C. Note that freezing kills parasites only, not unicellular microorganisms. So if in doubt or if serving immune compromised persons, go for pasteurizing. Regards Pedro

jk1002: I did not find Jean-François' test on sousvidecooking.org, would you mind posting a permalink? Okanagancook: Julabo offers floating hollow plastic balls, see http://www.julabo.de/database/add_downloads/8970010.pdf for covering sous vide baths, but you have to order 1000 pcs.; I use ping-pong-balls instead to cover the water surface. Spheres ideally cover 90.7% (i.e. the area of a circle divided by it's surrounding hexagon) of the water surface, substantially reducing heat loss and evaporation. My VEGA stockpot (9L 400W side-heater, controlled by a SousVideMagic 1500B) covered with the original sheet metal lid consumes about 54W in steady state at 55°C; with ping-pong-balls instead of the lid, power consumption is reduced to 43W. I also have a FreshMealsMagic (controlled by a SousVideMagic 1500D) with a 18L polycarbonate pot; filled with 13L water and covered with ping-pong-balls, it consumes 116W in steady state at 55°C; insulated with a triple layer of bubble wrap plus a cover made up of four layers of bubble wrap sealed in a vacuum pouch and floating on top of the ping-pong-balls, power consumption is reduced to 42W. Using plastic spheres instead of a lid allows for easy insertion and retrieval of food pouches, especially when they are suspended on a skewer to keep them in a vertical position, and with your IC it should also avoid condensation on the power outlet.

I totally agree with dougal. Some time ago, I tried to close my gap in education concerning temperature sensors, and it took me quite some time of googling. Here is part of what I found: Thermocouples: Temperature difference between two bimetallic junctions produces a temperature-dependent voltage. K-Type: NiCr (pos.) with Aluminium-plated nickel (neg.) -> 0°C … +760°C J-Type: Fe (pos.) with Constantan (neg.) -> 0°C … +1260°C T-Type : Cu (pos.) with Constantan (neg.) Thermistors (= Temperature dependent resistors = RTD =Resistance Temperature Detector): Applied measuring voltage causes a current in the sensor which heats the sensor, so they work best with a strong circulation of the surrounding media. PTC (= positive temperature coefficient, cold conductors) PTCs can be made of polycrystalline Titanat-ceramics like BaTiO3, with doting atoms, or of pure metals, typically Platinum. Pt100 has 100Ω at 0°C -> -200°C … +1562°C Pt1000 has 1000 Ω at 0°C NTC (= negative temperature coefficient, hot conductors) Made of Fe2O3, ZnTiO4, MgCr2O4 semiconductor materials. NTC 10 has 10k Ω at 25°C NTC 20 has 20k Ω at 25°C NTC 30 has 30k Ω at 25°C NTC 50 has 50k Ω at 25°C NTCs often are defined at 20°C (R20) The New Splash-Proof Super-Fast Thermapen is a K-type thermocouple, NIST-calibrated to ±0.4°C. Beware, it has a trim potentiometer, so you can destroy the factory-calibration. My Greisinger GMH-3710 high precision thermometer http://www.greisinger.eu/index.php?task=2&wg=26 (accurate to ±0.03°C) has a Pt100 thermistor. The PID-controllers from FreshMealsSolutions and Auber Instruments have NTC 50 thermistors. Generally, thermocouples are faster and thermistors are more accurate. @Merridith: What did you mean by "Thermapen or other thermocouple type digital IR thermometer" ? The Combo Thermometer IR + Fold out Probe http://www.thermoworks.com/products/ir/combo_thermometer.html ? This would be accurate to ±1°C only.

OK, now I am really confused. 52C for tender pork sounds very, very rare if not raw to me. So apropos of our recent discussion, may I assume you are not cooking it for more than 4 hours? I'm not sure I understand what "tender pork" is other than a tenderloin. Most pork chops seem pretty tough to me even when brined in a 7% brine for 3 hours before bagging (how I handle my pork chops). Also, at 52C, how long are you cooking say a 15 cm thick slab? I cooked a boneless pork shoulder for 48 hours at 60C it was still plenty pink, juicy and tender. I have done 10cm chops for one hour at 58C, I would like to do it a little less (say 57C)because the loin chops I use are so lean. What would you recommend. Thanks. Merridith, sorry for not having answered sooner. It is my personal experience with pork tenderlon and pork neck that they need a lower core temperature than beef tenderloin or prime rib or lamb racks to give the same feeling of medium-rare; one might expect it to be the other way round, but that's just my experience. A 15cm thick slab would be a mighty piece of roast, so I assume you mean 15mm thick, which heats from 3°C to 55°C in 18 minutes (Douglas Baldwin's table 2.3). Assuming "10cm chops" is 10mm, it would need only 8 minutes. And yes, I do not cook tender meat longer than 4-6 hours. Thermapen http://www.thermoworks.com/products/thermapen/splashproof_thermapen.html is specified to be accurate within ±0.4°C; if you have 4 thermometers reading within ±0.1°C, odds are high that they are correct. (Our mathematician could tell you how high). I assume you have read my article http://sousvide.wikia.com/wiki/Thermometer_calibration Regards Pedro

See http://www.sousvidecooking.org/foie-gras-cooked-sous-vide-58-degrees-during-47-minutes/ (58°C/47min) and http://forums.egullet.org/index.php?/topic/95886-roasting-or-poaching-a-whole-foie-gras/page__view__findpost__p__1313028 (60°C/25-30min). Viktor Stampfer (Sous-vide, Cooking in a vacuum) recommends 20min in 56°C waterbath for core temp. 54°C.

I'm not sure if that would happen Pedro. The frozen state of water is larger than its thawed state so we can surmise that the frozen fish will be expanded beyond its normal size and vacuumed in that state. Given this, as the fish thaws it is likely to shrink somewhat. It is therefore possible that the vacuum will not be as strong on the reduced sized and now-thawed fish. Definitely worth an experiment to see if it affects texture. Density of water is 0.99987 at 0°C 1.00000 at 3.98°C 0.99025 at 45°C i.e. from 0°C to 45°C there is about a 1% expansion. I agree it would be worth an experiment (Dave Arnold??).

Larger cuts will lose less juice, so cook the intact roast sous vide (e.g. 48h/55°C; with higher temperatures there is more liquid loss) and cut into chunks just before searing and adding to the sauce which you prepared separately. As an analog example see And of course well marbled roasts will come out juicier than lean roasts. If you keep braising the traditional way, you might consider Harold McGee's rules: My two cents: never exceed 78°C, as at 80°C and above meat will turn into shoe leather.

I suppose that the fish is frozen before being cryovacced. In the frozen state, a 99.9% vacuum of a professional chamber vacuum machine will not affect the texture of the fish, but as soon as it is thawed, this high vacuum may compress it and deteriorate the texture (cf. post #2). So it would be better to transfer the fish to a Ziploc bag (or Foodsaver bag, but with minimal vacuum) together with your preferred ingredients. For cooking sous vide, it is not necessary to thaw the fish first, just drop it in the water bath, and use the old rule of thumb "increase the cooking time by 50% when cooking from frozen", as Douglas Baldwin provided cooking time tables for thawed fish only in his Practical Guide http://amath.colorado.edu/~baldwind/sous-vide.html