PedroG

For vacuum sealing with marinade, see

Lava V333 is overkill, V100 http://lava-vacuum-packing.com/V100.htm is sufficient, as well as FoodSaver™ V2040 http://www.foodsavereurope.com/Products/ProductDetails.aspx?pid=121 . You do not need high vacuum, but an instant-seal-button is recommendable. MagicVac Elite will do as well, mine is more than 10 years old and still working. Regards Pedro

Your bags seem to float horizontally, which makes temperature uniformity and heat transmission in an unstirred bath even worse. You might try to suspend your bags on a skewer (see ) and eventually clamp a table cloth weight (this idea is from Bob Jueneman) to the bottom rim of the bag: Covering the bath with ping-pong-balls reduces heat loss and water evaporation, and a simple indoor fountain pump (mine supported 59°C without problem) may substantially enhance water circulation and temperature uniformity, see

See (posts #5-#25) and http://amath.colorado.edu/~baldwind/sous-vide.html chapter "Maillard reaction". In post #16 Douglas Baldwin says: BTW browning meat is the "Maillard reaction"; caramelization concerns sugars only, not amino acids. Regards Pedro

Nicolas, as you say in your blog: the problem really seems to be in the connective tissue and not in the muscle fibers, which might confirm my suspicion that it was a piece of meat with too much elastin; I had such an experience as an Xmas flop! I have no experience with brining, maybe Douglas Baldwin can enlighten you. Regards Pedro

Many of us prefer brisket 48h/55°C, this is the lowest temperature that can be recommended from a safety point of view, and it comes out nicely pink and succulent. See http://sousvide.wikia.com/wiki/Marinated_Brisket and . At temperatures over 59-60°C collagenase gets inactivated, so you miss the enzymatic splitting of collagen and fully depend on heat induced breakdown of collagen into gelatin which is faster the higher the temperature. If a "brisket" does not come out fork-tender after 48h/55°C, they may have sold you meat from a different part of the animal which contains more elastin than collagen, and elastin will never dissolve. See also Douglas Baldwin's Practical Guide: http://amath.colorado.edu/~baldwind/sous-vide.html

Some googling taught me that vacuum bags by FLAEM NUOVA (MagicVac), FoodSaver and LAVA are made of an inner layer of PE (polyethylene) and an outer layer of PA (Polyamid/Nylon), and that they are safe for freezing, boiling and microwaving (provided you puncture the bag before microwaving). LAVA and MagicVac say their bags can be used with other brand vacuum machines, FoodSaver say no. See http://vacuseal.com.au/skin1/images/vacuseal_catalogue.pdf page 15

sheepish: Vacuum bags usually are made of PE (polyethylene) or a combination of PE and PA (polyamide). See http://en.wikipedia.org/wiki/Low_density_polyethylene : LDPE ... can withstand temperatures of 80 °C continuously and 95 °C for a short time. So I should expect vacuum bags to withstand temperatures usual in sous vide cooking, i.e. 43°C (fish) up to 80°C (vegetables), and in my experience they actually do withstand 78°C, but they are not made for boiling. At boiling temperature, water (contained in food) becomes steam, so any sealed bag (irrespective of the vacuum level) will balloon and float and eventually get ruptured. jk1002: Some vegetables and fruits contain air (that's why you can vacuum-infuse them with liquids, see http://sousvide.wikia.com/wiki/Instant_rum_pot , this works even with clamp-type machines to some extent), and at higher temperatures this air will expand and make the bag float. So for cooking vegetables sous vide, a rack might be appropriate to hold the bag in position. I always suspend my bags on a skewer which keeps them in a vertical position and apart from each other, whereas just dropped in the water, they tend to lay horizontal and float.

Waterbath temperature stability and temperature uniformity How much temperature oscillation is acceptable for sous vide cooking? Douglas Baldwin http://amath.colorado.edu/~baldwind/sous-vide.html says ±1.2°C will do for most sous vide cooking. The Sous Vide Supreme is specified to be stable within ±0.5°C, LoftyNotions reports it to be stable even within ±0.5°F (±0.25°C), which should be comfortable for most sous vide cooking. With my SousVideMagic 1500B and VEGA 400W sideheater stockpot with forced circulation (indoor fountain pump) I have stability within ±0.07°C, see and with the SousVideMagic 1500D and a pre-production model of the FreshMealsMagic stability is similiar (after some PID-tuning). With laboratory immersion circulators stability may be ±0.05°C (Douglas Baldwin) or even in the milliKelvin-range, which in my opinion is an overkill for sous vide cooking. So, temperature stability with a Sous Vide Supreme may be sufficient, with an appropriately tuned PID-controller (Auber or FreshMealsSolution) it is very good, and with an immersion circulator it should be even better and rather an overkill. How is water bath temperature uniformity with / without forced circulation? I did a test with the SousVideMagic 1500B and VEGA 400W sideheater stockpot, mounting one sensor of my Voltcraft K202 data logger (resolution 0.01°) near the vessel wall together with the SousVideMagic's sensor, and the second sensor was a few millimeters near an iceBrick which I introduced to simulate addition of a cold pouch of food. With forced circulation by an indoor fountain pump (which has supported temperatures up to 58°C so far), deviation of temperature at the center of the bath to the periphery of the bath is between -0.2°C and +0.3°C Without forced circulation, deviation of temperature at the center of the bath to periphery of bath is between -1.7°C and +0.3°C; maximum deviation is during initial heating. Deviation during disturbance dip is significantly more pronounced than with forced circulation. So, for longtime cooking (24-48h) forced circulation may be optional, but for short time cooking or for adding pouches while another pouch is long-time-cooking, forced circulation is strongly recommended. It would be interesting to see a similar experiment with a Sous Vide Supreme and with a rice cooker (bottom heater). Who is going to undertake and publish these experiments?

Brisket „Stroganoff“ Sous Vide With Mixed Mushrooms Ingredients for 2 servings about 400g well marbled Brisket 3 tablespoons rice bran oil or other high smoke point oil (grapeseed oil) 3 tablespoons extravirgin olive oil 3 tablespoons Cognac (brandy) 2 small onions, finely diced ½ yellow or red bell peppers cut into strips 90 g mixed mushrooms 100 ml of gravy from last Brisket (or concentrated stock) 1 teaspoon mustard, Dijon type 1 teaspoon paprika mild (not spicy!) 1 medium pickled cucumber cut into thin strips 2 tablespoons parsley, finely chopped approx. 120g sour cream with herbs Sous Vide - cooking Marinate brisket with Mexican style (medium hot) marinade in the vacuum bag for at least 3 days at 1 ° C, cook sous vide 48 hours at 55.0 ° C. Preparing the sauce At a moderate heat sauté onions in olive oil, add peppers (preblanched in the microwave oven for 2-3 minutes) and mushroom mixture, stir-fry, remove from heat and add the gravy. Add pickled cucumber, pepper, mustard and cognac. Put on very low heat, add sour cream and keep warm, but do not boil as the cream will separate. Remove the brisket from the bag, cut into strips (about 8x10x35mm), sear very quickly in smoking-hot rice bran oil, add the meat and the parsley to the sauce. Serving Serve on warmed plates. Typically served with spätzle (south German) or chnöpfli (Swiss). And don't forget a glass of good red wine! Enjoy your meal! Pedro

Some meats (like spare ribs) seem to need to be cooked at temperatures at which the fat will really render. I haven't done pork butt at temps these low so I don't know, but I suspect that it will be better cooked at significantly higher temperatures. For some cuts, like short ribs and brisket, you need to choose pieces where there isn't too much interior fat. For short ribs, I make sure that they are trimmed of most of the exterior fat (since I like the texture at 135F/48 hours at which time the fat is still unrendered). So, it may be a matter of picking the right short ribs to cook. I am very curious about your brisket experience. What sort of brisket was it? And how trimmed was it to begin with. When I have cooked it, even at 48 hours most of the exterior at was still there (fortunately soft and easy to remove before slicing)? Was it interior fat or exterior fat that rendered? Is it possible that it wasn't a significant amount of fat rendering but some combination of the fat and gelatin? I ask because the interior marbling of my briskets was nice and soft and melt in your mouth, but not very rendered. Of course, there might be a huge difference between 48 and 72 hours in this regards. Juiciness is an interesting topic -- because there are a few things at play -- the actual moisture content and the subjective experience which seems to be mostly about mouth-feel. The muscle fibers start to shrink significantly as heat goes up so it forces out moisture -- which may or may not be reabsorbed as the meat cools. My own personal experience is that in some cases, the mouth-feel created by the rendered fat can play into one's perception of juiciness. So, even spare ribs that are well-done can seem "juicy" because of the mouth feel. And spare ribs cooked below the temperature at which the fat renders can seem to be not as juicy (because they are missing that lovely lubricating grease). I had an experience of some dry mouth-feeling with a falling-apart-tender veal shoulder 48h/55°C which seems to be too long. I had chilled the second piece of the same veal shoulder and yesterday reheated 2h/55°C, then cut in cubes, seared and served in my Stroganoff sauce http://sousvide.wikia.com/wiki/Brisket_Stroganoff , and the mouth-feeling was definitely more juicy. My next veal shoulder will be only 12-24h/55°C. BTW I always use the the gravy from the last long-time-cooking and preserve the actual gravy in a glass, heating in the microwave to pasteurize and keep it refrigerated.

Excellent post Pedro. I would like to throw in an additional thought. Unless there is a compelling need to cook at the edge of safety, I think it is wise -- even if you have calibrated your setup -- to give yourself a margin of safety that is beyond the theoretical precision and accuracy of one's equipment. I have had an enlightening email exchange with Suyi Liu -- the designer of the Auber Instruments PID Devices (which were sold by Fresh Meal Solutions as Sous-Vide Magic until late last year) -- in which he explained calibration drift, etc. I will summarize that information in another posting in the next few days. Long story short, these devices can (but may not) experience calibration drift over time -- usually such a drift is fairly small but under certain conditions can be a few degrees -- as can the high-precision thermometers used to calibrate the devices. Because various things can cause your system to drift slightly over time, it is wise when pasteurizing to give yourself some additional margin of error. In most cases, when pasteurizing, this is happening at temperatures and with proteins where cooking at one degree or two degrees higher than the margin should have minimal impact on texture but will have a huge impact on safety. Also, these devices need to be calibrated to a temperature between 65F and 145F or so. Within that range they are (when functioning properly) accurate to less than 1/2 degree Fahrenheit. So, you can't do an ice water or boiling water calibration since those temperatures are well outside the range where the probes operate correctly. Safety: With the usual 55°C for longtime cooking I am well above the 52.3°C (limit of C.perfringens thriving), and with my SVM 1500B and VEGA 400W sideheater stockpot with forced circulation (indoor fountain pump) I have stability within ±0.07°C. For additional safety I routinely marinate my meat to lower the pH below 4.1, which even allows me to let the meat age at room temperature for 24 hours. Drifting of temperature sensors: I (and Robert Jueneman and blackp) experienced this with the first sensors FMS delivered with the new SVM 1500D, as there was a problem at the junction of the cable and the mantle tube of the sensor. They seem to have fixed this, the newest sensors have so far tolerated permanent immersion and temperature changes.

Here are the links to Nathan's famous charts: 5°C to 54.4°C: 5°C to 45.0°C: 5°C to 60.0°C: and his tutorial:

"The time has come," the Walrus said, "To talk of many things: Of germs - and molds - and botulism - Of meat and fish - and pasteurizings - And why the searing is so hot - And what the PID-controller brings." Most of the posts from #3210 to #3250 deal with food safety aspects, temperature/time combinations, and accuracy of temperature measurement and stability. So it seems justified to compile a few data. They may be found in http://www.hi-tm.com/homeprep/Home-2006-2col-forpdf.pdf and http://www.hi-tm.com/RFA/food-path-summ.pdf and http://amath.colorado.edu/~baldwind/sous-vide.html Food safety and spoilage: Meat and fish is safe below 29.3°F/–1.5°C (Listeria monocytogenes is the limiting pathogenic microorganism). However, spoilage bacteria begin to multiply at 23°F/–5°C. So with improper refrigeration, spoilage will begin before pathogen multiplication. Food can be safely held at or above 126.1°F/52.3°C (Clostridium perfringens is the limiting pathogenic microorganism). The upper limit of the “danger zone” has arbitrarily been set to 130°F/54.4°C in the FDA Food Code. After cooking, the food must be rapidly chilled in ice water (crushed ice/water 1:1) to prevent spores of Clostridium perfringens from becoming active bacteria and producing toxins. If the food is safe to eat raw and you are not pasteurizing it, then the FDA Food Code requires that it is between 40°F/ 4.4°C and 130°F/54.4°C for less than 4 hours. Surface pasteurization by dunking or pre-searing: A 6.5D reduction of Salmonella takes 85 seconds at 149°F/65°C, 11 seconds at 158°F/70°C, 1.4 seconds at 167°F/75°C, and 0.17 seconds at 176°F/80°C. So when dunking, add 30 seconds for heat penetration through the bag and a 1mm surface layer, and you are on the safe side. Pre-searing would theoretically sterilize the surface, but handling during cooling and bagging before vacuum-sealing may introduce new germs. Importance of accurate temperature control: Pasteurization (a 6.5D reduction of Salmonella) takes 110 min at 54.5°C or 89 min at 55.0°C, so when relying on the pasteurization times looked up in Douglas Baldwin’s tables (http://amath.colorado.edu/~baldwind/sous-vide.html ), a temperature variation of ±0.25°C makes a significant difference, although this would rather not influence the organoleptic outcome. However, in Douglas’ tables there is already a safety margin. If a 0.1°C error of the SousVideMagic’s sensor adds up with a ±0.1°C oscillation of water bath temperature, this may already result in a 0.2°C error. When using a SousVideSupreme with a specified “sensitivity” of ±0.5°C (accuracy is not specified), safety margins have to be accordingly larger. Whatever your SV equipment is, a calibrated reference thermometer is highly recommendable, and quoting Bob Jueneman (post #3232 ), funeral expense cost a lot more than a thermometer calibration! Thanks a lot to Douglas Baldwin for proofreading this post and making corrections in the “food safety and spoilage” section. We are looking forward to further clarification by Douglas Baldwin. Pedro

Can you describe this "odd smell/taste" more precisely? Was it still pink? Was it falling-apart?

[quote name=PedroG' date='31 January 2010 - 12:37 AM' timestamp='1264894657' Interesting article. Thanks for the link. If I read the graph correctly, at temps above 55C the maximum error is less than 1C and doesn't happen until 90C. Yes, and fortunately all sensors had minimal deviation at 55°C, as you can see in my original spreadsheet http://www.mydrive.ch/download/50434411/1500D_sensor%20calibration_on-the-fly_25-90%C2%B0C.xls

I agree with e_monster that digital ovulation thermometers are not generally unacceptable as a secondary standard. I have a "Cyclotest Lady" by UEBE Medical GmbH in Wertheim, Germany. It has a resolution of 0.01°C and is specified to be accurate to ±0.10°C. In fact, its offset against my ISO-calibrated Greisinger GMH3710 high precision thermometer was -0.06°C at 33°C and +0.01°C at 42°C, see http://www.mydrive.ch/download/50592073/Calibration_GMH3710_SVM1500A_testo_Mastrad_GourmetCheck.xls By extrapolating from 33-42°C to 55°C, we might risk to be 0.5°C off, but this is still better than no calibration at all and just trusting any junk thermometer, and regular checking of the SVM sensor against an ovulation thermometer may indicate a beginning shift in the sensor (some sensors do not withstand permanent immersion for many months or years). BTW in the ominous 54.4°C safety limit, there is already a safety margin of at least 1.4°C, see http://www.hi-tm.com/RFA/food-path-summ.pdf So longtime cooking at nominal 55°C should be safe even with a 1.5°C deviation of the sensor. Pedro

See comments Interesting article. Thanks for the link. If I read the graph correctly, at temps above 55C the maximum error is less than 1C and doesn't happen until 90C. Yes, and fortunately all sensors had minimal deviation at 55°C, as you can see in my original spreadsheet http://www.mydrive.ch/download/50434411/1500D_sensor%20calibration_on-the-fly_25-90%C2%B0C.xls The non-linearity seems to mostly be in a temperature range where for proteins a variation of 1C isn't going to make a critical difference. For most applications, there won't be much difference between cooking at 75C vs 76C even after many hours. I absolutely agree. Did you repeat the trials enough times to find the non-linearity predictable? No, this is not something you can simply record with a data logger, I set up my digital camera to take a picture of all the displays at 30sec intervals and then I entered all the data into the spreadsheet. If so, it would seem that one could have an offset table that should have you pretty close. The easiest temperature for most people to calibrate to is in the range of 36C to 38C since very accurate (+-.2C) thermometers can be purchased for less than $20. I should prefer those sous vide geeks who have a NIST or ISO calibrated high precision thermometer to offer a one-point-calibration service (55°C) for other sous vide home cooks living in their region. Or manufacturers of PID-controllers could offer this service for a given controller-sensor-combination at a reasonable cost, then the user can compare his sensor with a basal temperature thermometer at 37°C and recheck this at regular intervals. Regards Pedro Edit: Frank Hsu of FreshMealsSolutions just told me:"We are now calibrating all our 1500D units/with the sensors before we ship them out to customers. We use the Lada pt100 calibration bath and is accurate to 0.1C and better."

See my article on thermometer calibration on sous vide wikia: http://sousvide.wikia.com/wiki/Thermometer_calibration . Calibrating against a basal temperature thermometer at 37°C is better than not even thinking of calibration, but nobody garantees your working thermometer or your sensor has a linear temperature response curve that parallels the one of a calibrated high precision thermometer. SousVideMagic 1500A/B have 5k sensors that in my experience are correct at 55°C but show low at lower temperatures and high at higher temperatures. SousVideMagic 1500C/D have 50k sensors that parallel the temperature curve of my ISO-calibrated high-precision thermometer.

In my experience, pork needs lower temperatures (52°C/126°F) than beef filet (54-55°C/129-131°F), and especially lean pork is prone to feel dry. In a pork chop typically the fatty portions are fine, but the lean part feels dry most notably in continued chewing. Juiciness at first bite is the juice in the meat, but in continued chewing, it is the saliva provoked by fat, spices, maillard products, marinade. Over-compression is a problem in fish and to some extent in poultry, but not so much in beef and pork, see http://www.cookingissues.com/2009/06/17/boring-but-useful-technical-post-vacuum-machines-affect-the-texture-of-your-meat/. Clamp type vacuum machines rarely produce a vacuum stronger than 80%, so with these over-compression is not an issue. (See http://sousvide.wikia.com/wiki/Find_out_how_strong_a_vacuum_your_machine_produces ).

At what temperature did you cook your beef filet? I do not have the book of Thomas Keller, but I suspect that his recommended temperatures are much too high for legal reasons.

Just a little patience, as an addendum to the 1500D user manual http://www.freshmealssolutions.com/ will soon be coming out with a PID-tuning document which is coauthored by three of us EgulleterSousViders. Associated with it will be an Excel sheet to evaluate tuning results, you find a preliminary version here: http://peter-gruber.gmxhome.de/SV/TESTING_PID-SETTINGS.htm . Any suggestions are welcome, I might refine this spreadsheet. Regards Pedro Thank you, I will be eagerly waiting for this guide! The "Guide to PID Control for Sous Vide Cookery" is now on-line at http://www.freshmealssolutions.com/downloads/PID1500Dtuningguiderelease1.pdf Pedro

It is not surprising that the settings vary from what is mentioned in the manual. The manual (at least the one that comes with the Auber Instruments version) makes it clear that the settings represent ones that worked for the particular devices that they used and that you are likely to need different settings if you use different equipment. Devices that heat from the side are especially challenging because the weak convection currents results in irregular latency. Adding a bubbler (you don't even really need the airstone) will help. And you should re-auto-tune once you start using the bubbler because it significantly alters the dynamics. Other people's settings may be of limited use unless they are using near identical equipment. The settings they give as the default work almost flawlessly on my Presto Multicooker (which only heats from the bottom) but are far from optimal from any of the 'side-heating' devices that I have tried. SousVideMagic 1500A and 1500C do autotuning with a hysteresis of ±0.5° (C or F), whereas the 1500B does autotuning with a hysteresis of only ±0.1°C, which in my experience gives less reliable results. Try autotuning with the 1500C in Celsius mode and use these values on the 1500B!

Just a little patience, as an addendum to the 1500D user manual http://www.freshmealssolutions.com/ will soon be coming out with a PID-tuning document which is coauthored by three of us EgulleterSousViders. Associated with it will be an Excel sheet to evaluate tuning results, you find a preliminary version here: http://peter-gruber.gmxhome.de/SV/TESTING_PID-SETTINGS.xls . Any suggestions are welcome, I might refine this spreadsheet. BTW with your Banquet Meal Maker BSC400 which seems to be a rectangular side-heater, I should strongly recommend using forced circulation with an aquarium bubbler (for higher temperatures) or an indoor fountain pump (mine works fine up to 58°C). For better insulation, you might cover the water surface with ping pong balls. Regards Pedro You find Bob Jueneman's "radically condensed version" of the above-mentioned PID-tutorial here: http://chowhound.chow.com/topics/678636#5304760 When googling "PID-Controller" you will find many descriptions and tutorials, e.g. http://en.wikipedia.org/wiki/PID_controller or http://www.learncontrol.com/tutorial/index.html . Please note that different authors define parameters differently. The proportional band P is in degrees in SousVideMagic controllers; in 1500A/B/C P=10 is 1.0°, whereas in 1500D P=10 is 10.0° (at least in the pre-production model it was so). Other authors define P as gain, where Proportional Band = 100/Gain. The integral parameter I may be defined as repeat time in min or sec or as repeats per min or repeats per sec. In all SVMs I is repeat time in seconds; the higher the value, the weaker the action, a zero value means infinitely weak action. The derivative parameter D is in seconds in all SVMs. The higher the value, the stronger the action, and zero value is zero action. Other authors use gain which is reciprocal. All clarities cleared? To download my spreadsheet "TESTING_PID-SETTINGS.xls" please use the following link: http://peter-gruber.gmxhome.de/SV/TESTING_PID-SETTINGS.htm which will link you to the actual version of the file. The filename will now contain a version number. Pedro

See and http://books.google.ch/books?id=iRlnToZbRxEC&pg=PA274&lpg=PA274&dq=thermal+conductivity+bone+meat+fat&source=bl&ots=0nFgEkkMjN&sig=-3jV-JMz2lAmdgfu050tAHKiHP8&hl=de&ei=kbZHS8uZMYvJ-QbHr_1w&sa=X&oi=book_result&ct=result&resnum=1&ved=0CA4Q6AEwAA#v=onepage&q=thermal%20conductivity%20bone%20meat%20fat&f=false which states the following thermal conductivities in W/m/°C: Lean meat 0.49, fat 0.21, compact bone 0.56, spongy bone 0.26, bone marrow 0.22 In marrow bones which are mainly from the shaft (diaphysis) of the bone, the major part of the bone is compact bone with thermal conductivity similar to meat; cuts approaching the joint (epiphysis) contain more spongy bone which acts as an insulator. So both McGee and Wolke are right, it depends on what kind of bone is concerned.