nathanm

These things are great - I have several. I like them particularly for hydrating (dissolving) hydrocolloids. For SV they work fine. Note that you really must stir them - so those with integral magnetic stirrers work best. Also, you need to have one that has a temperature probe. The best ones are digital with a built in PID contoroller, but naturally they are more expensive. As mentioned above a PID controller can also be added to simple magnetic stirrer/hotplate if you into a bit of electronics hardware hacking.

There are many options here. The first big decision is between SV served immediately, and SV that is chilled, stored and reheated. 1. For very fast cooked items, you can cook to order and serve. Most fish dishes would be a good example, because I like cooking fish at a lower temp then would be a good idea for cook-chill-store. Cooking time is kept short so they can be cooked to order in the water bath or combi oven. The key to short times is to keep the pieces thin - cutting the thickness in half cuts cooking time by a factor of 4. 2. Food cooked up to sterilizing time-temperatures combinations (i.e. the FDA time-temperture tables) can be held at 130F/54C (or cooking temperature if higher than that) all through service. If you sell them - great - use them directly. If you don't sell them then at the end of service you can rapidly chill them and refriderate and treat like cook-chill-store SV - see below. 3. Or you can do cook-chill-store from the onset, in which case you cook the food SV, then rapidly chill (immerse in ice water, or use blast chiller). 4. Regardless of whether you chill right after cooking, or after service store the cooled bags no more than 4 days at 7C/45F, or 7 days at 5C/41F, or 1C/34F for 30 days (this is US FDA SV rules). Or if you freeze them, you have much longer. Reheat by putting into a water bath or combi-oven. The time table for reheating is the same as cooking in the first place - at least to come up to tempertaure. So, as a pratical matter, with lamb cutlets, I would cook them at 130F/54C, probably for one to several hours (depends on cut of lamb, how tender I want them). I would hold them at that temp during service. If they don't sell do the chill-store at end of service. Then store cold until ordered at which point you can reheat them. However, once you have chilled them, keep them cold until reheat and serving - don't take them out reheat then re-chill etc. With braised meat - say lamb shanks instead of cutlets, cooking time would be more like 160F/71C for 8 hours. You can then hold them during service at anywhere from 135F/58C to 160F/71C. If you don't sell them the first service then once again you chill and store. Depending on what effect you want you could do final sear at the end, or at the beginning.

It is possible to take tender meat and cook it too long - it gets too soft and the texture suffers. As per other posts I would cook lamb for just long enough to reach temperature - depending on the thickness (see the tables) this is likely a hour or less.

You can get ribs to fall off the bone at nearly any temperture if you cook long enough. However, the fat rendering doesn't happen much below 180F/82C. So, 180F/82C for 8-12 hours depending on the specific cut of meat. I would start at 8 hours and then move up if you wanted it more falling-off-the-bone. Note that when you do long times like this the exact value is not that important - 8 hours is not that much different from 9 hours, for example. You can cook them at higher temp - up to 200F/93C, and the times are shorter - say 2-3 hours for ribs. The same times/tempertures work for most meats that you want to braise and/or confit. The issue here is personal preference. A rare steak is a different experience than stewed beef. We are used to assuming that each cut has a particular cooking method - nobody stews a fillet mignon, nor do they grill stew meat cuts and serve rare. However, with sous vide you have the opportunity to achieve different effects. I have done osso bucco down to 130F, but the texure is so unfamilar, and the fat does not render. Most of all, people are very set in the ways and if you serve osso bucco that has a non-traditional texture it can freak people out. In general I cook osso bucco and lamb shanks confit style (i.e. with oil in the bag) at 180F/82C for 8 hours. But don't let that stop you from experimenting on your own favorite combination!

Somebody recently asked me for a URL to the tables I posted here. So I went back and looked, and the formatting has changed. They are in HTML, and this used to work fine and look great, but now it doesn't and raw HTML code is displayed. This must be some setting with eGullet Here is a link to the posts I am not sure who handles technical issues like this, but somebody at eGullet must...

This ought to work well. However there are two issues. First, you won't have smoke flavor. Smoking the meat at low temp for an hour prior to going in the bag makes a big difference. Second, 160F is kind of low for ribs, because you won't get any fat rendering. The meat itself will be fine. This is a matter of personal preference, but most people are used to having some fat render out of pork ribs, and you need higher temperature to achieved this.

That approach works well, but it costs you time. It is one of life's litte tradeoffs. The fastest way to transfer heat to food is with condensing steam - nothing else comes close. So using a Rational for steam gets you very fast heat up. If you put the water in the gastronorm pans, you definitely smooth out the fluctuations, but you also need time to get the water heated. For precise low temp work use the water, but for high temp where the fluctuation does not matter steam will be faster.

Unfortunately plastic is degraded by UV light, so I don't think this would work. You certainly could use UVC to sterilize the water in a water bath - small UVC units are used to sterilize water in aquariums, and one of these could be adapted. However, for most people it is cheaper and easier to just dump the water out. You certainly can tell the difference between 122F and 125F in the meat, but it is a fairly small difference which you might well decide is worth it.

There are lots of techniques for reducing surface pathogens. Simple rinsing is one approach - that is what most people do. It is called "washing" but in most cases people only use water. This works by diluting the pathogens - which helps, but only so far. Generally speaking most people do not use chemical or other disinfectants on food itself - only on pots, pans, knives and other kitchen surfaces. As Chef Z mentioned implictly there are various washing products from companies like Ecolab. Ozone in the water is an example; chlorine in the water is another. Exposing food to UVC, or putting the food under ultra high pressure are other approaches. Many of these approaches work, and to one degree or another are used commercially. The large E. coli outbreak in the US in 2006 in fresh spinach is one inspriation - people want to eat spinach salads, so they want it eat it raw, and cooking is not going to be answer. In the spinach case, cold water rinsing in the spinach plant is thought to be a big factor in the contamination - because once one small bit of contamination got into the washing tank, it spread to all of the spinach. Current thinking is that the problem was caused by feces of wild boar on the spinach. The boar went through fences to get into the spinach fields. The wild boar got the E. coli because they previously had broken into a nearby cattle ranch and ate infected cow manure. Sorry to be disgusting, but that is how these things work. E. coli H57:O157 is bad in humans but can occur in cows without symptoms. Even so, it is likely that it was only a few spinach plants out of many huge fields but the wash water spread it to many states - enough to make about 200 people sick and kill a few of them. Ironically, washing the spinach in the processing plant - in order to sell "ready to eat" spinach made things worse rather than better. If they had not washed the spinach there would have been many fewer cases. This incident has re-energized interest in the question about how to sterilize the washing water, or sterilize the spinach, without destroying it as a fresh raw food. I am not aware of restaurant or home chefs using any of these advanced techniques for reducing pathogen count, but some of them may do this. It is certainly feasible. One exception is that a few restaurant chefs who do their own meat aging use UVC lamps shining on the meat to reduce surface mold. This works well. My blast chiller has a UVC sterilization cycle where it automatically sterilizes itself, but that is about steriziling the chiller not the food in it.

Rationals are great - I have two at home and one in my lab. However, you should get them calibrated if you are going to use them for low temp SV. You can check this with a good digital thermometer, or the Rational service guy can. You want to make sure that the temp is accurate, and constant across all of your ovens. Even if calibrated there are larger temperture variations than with a water bath. The gas models can have 10F temp swings (when burner comes on). The electric models are more like 5F, but still, this can make a difference. Knowing the variation can help you plan the temp. So, if you are cooking fish at 113F/45C, and the actual temp is going from 110F to 116F, you need to know that. For higher temperture work the variation is less important. That sounds about right. Sweet corn and other vegetables seem to be best around that temp. Many other vegetables need cell walls broken down, which takes more time and temperture. Carrots at 150F will be almost as crisp as raw, for example. This sounds fine, and is within FDA guidelines for SV. The key issue is keeping it cold and not holding too long due to botulism. 150F for 8 min is enough to kill everything except C. botulinum spores. 41F for 6 days is within guidelines for holding.

Correct, there is no difference doing it sous vide, or conventionally. C. perfringens and certain other pathogens are anaerobic, but if they are inside the steak (and that is a big if) that is an aneorobic enough environment. Sous vide does not change this a bit.

No, that occurs at lower temperture - around 100F. To get that effect you hold the meat at that temp for a few hours. By 122F the enzymes are mostly denatured. First off, there is no single correct answer to this question. The interior of intact muscle meats are almost always sterile. Contamination is on the surface - unless somebody poked a knife through the surface and thereby brought some contamination inside. Also, you should know that virtually all of the meat bought in a Europe or the US is not contaminated. So, most likely, nobody would get sick if you did this. Is there some risk? That is complicated. It might be possible for a couple of pathogens to grow inside the meat under these conditions - it is theoretically within the range that they could propagate. Clostridium perfringens is one example. However, to know for sure one would have to do scientific tests, in beef, under these circumstances. C. perfringens is not normally found in beef, and would be an external contaminant. The closest thing in food safety literature is that pork hams infused with a brine contaminated with C. perfringens can run into trouble in these tempertaures. However, that is only with slow cooling through the temperture range - not holding constant, and that is pork not beef. Since meat interior is sterile in almost all cases those pathogens are probably not going to be there. At a certain point one has to realize that obsessing about risk in one area is odd if you don't do it elsewhere. Will you ride in a car to buy the meat involved? Your risk of death or injury in a car accident is actually pretty high - tens of thousands of people die that way every year, a figure that dwarfs all food borne illness deaths. A separate question is whether this is OK according to food rules. Technically one could argue that the method described above is OK with the US FDA 2005 Food Code, since it specifies that in the case of beef steak if the exterior is brought to 145F, they do not care what you do to the interior temperture. Or, one could argue that a blanket rule in another part of the food code says that no food should be in the "danger zone" between 40F and 140F for more than 4 hours. It is unclear which rule applies here, and it would wind up being a legalistic reading of the rules that tells you the answer. Industrial food companies often get a specific process approved by doing tests or computer simulations. Heston does this also on occaision, and may have done that here. There are sous vide techniques where you use a hot bath initally as you suggest to destroy pathogens, so the concept works. However, frozen meat in boiling water would likely need to be in for more than 30 seconds in order to get the exterior to the right temperture /time combination for sterilazition. You could do some experiments with a temperure probe to find out. Or look at the meat - you need to have the exterior visibly change color (and look like meat cooked to 145F to 150F). However, it may be just as easy and more certain to sear the exterior, which you could do frozen or not frozen (but cold).

There are a bunch of low temperture steamers - the key here is low temperture rather than high temp steam. Steam is important to get good heat transfer, and to prevent evaporation from the food. Sous vide solves those problems by putting the food in a bag where there is essentially no air, and no evaporation. You can use a low temperture steamer to cook sous vide instead of a water bath (but temperture control is nowhere near as good). Or, if the food will tolerate getting wet, you can cook in it without a bag. There is no magic in calculating the FDA times - it just means it has a timer, and a table of time/temperture. There are many other brands besides CVAP. For some reason New York city chefs discovered Winston CVAP - I think Wylie may have been first - and it spread like wildfire in the last year or two. But in reality it is a very old technology and there are tons of brands with essentially the same specs. Rational (and other brands) of combi-ovens have this sort of functionality too, but they also do much much more. Most low temp steamers have a thermostat, which injects steam as needed to keep the temperture constant (but typically are off by +- 2 degrees and often +- 5 degrees F). The most technologically interesting low temperture steamer is Accutemp. Their systems maintain the temperture a bit differently - it actually pulls a vaccum in the chamber to lower the boiling point of water. This improves heat transfer, and has some other small advantages. The same company also has a very interesting griddle.

I'm working on the book, but it is going to be a little while yet. CVAP is a low temperture steamer. It is similar to low temp steam mode on a Rational combi-oven, but not any better. Rational has many other modes so is a lot more versitile (and also more expensive). It can do high temp steam and humidity controller roasting and baking.

The 2005 FDA food code goes down to 130F/55C for most meats - there are time & temperature tables. There is no problem with 130F. If you have an intact muscle - i.e. steak or roast - then FDA does not specify any minimum internal temperature - just that the exterior must be brought to 145F/63C. Of course serving carpaccio is legal, as is warm carpaccio. According to FDA you have 4 hours between 40F/4C and 140F/60C. So if you wanted to serve beef at 100F/38C you could, so long the total amount of time it spends above 40F/4C is less than 4 hours. Those are official guidelines. They are conservative Pragmatically speaking I routinely cook at 122F to 125F for red meat for many hours. That is both technically legit up to 4 hours. Beyond 4 hours there is scientific data that would say that 125F is more than enough, and certainly 127F - which is why the conservative FDA sets it at 130F. However, usually when I am cooking for a very long time, I use 130F because you want the highest temp you can for denaturing collagen. At 125F the times would be substantially longer than at 130F. That is all red meat. Other things get lower tempertures. I cook Fish down to 100F/38C, but I do not do that for very long (certainly less than 4 hours).

I agree that it's not silly to inquire and explore. But I still think it has limited usefulness. That said, I am absolutely open to the possibility that I could be widely mistaken on this. So, in the spirit of inquiry, exploration and discussion. . . Well, for what it is worth, I think you are both right to some degree. Cooking changes meat irreversibly - due to various chemical reactions brought on by heat. Most of these reactions are very fast - essentially instantaneous. There are also a few reactions that are slow. Collagen denaturing into gelatin is one of those, but there are also enzymes that effect the meat between 100F/38C and 120F/49C. There are other slow reactions at high temperature. So, if meat reaches a temperature threshold - say 170F, then all of the fast changes will happen regardless of holding at lower temperature afterward. Slow reactions will occur over a period of time. Rational combi-ovens have an automatic program for roasting big pieces of meat that does this. First it preheats the oven to 500F/260C, you put the roast in with a thermometer probe. It sears the outside to brown it (for appearance and flavor), then it cools the oven down and puts it in low temp steam mode and steams for many hours, bringing the meat up to temp (say 130F/55C, but whatever you set) and holding it there for 24 hours. You could do the same thing with SV by browning first, then cooking SV. Or you could SV first and then brown. As discussed previously in thread there is very little difference. You might get more flavor transfer from the browning. In the combi-oven the reason you brown first has to do with food safety - there is no bag to hold the meat as with SV, and since all food safety contamination is external, this serves to sterilize the outside. Otherwise if you held overnight at 125F, the health department might get mad (although in reality there is little or no danger). There is no special benefit (that I am aware of) from cooking at two temperatures. If you brown quickly at high heat then there is only a very minimal gray layer of overcooked meat immediately under the browned exterior. Cooking more slowly at high heat would give you a larger band of gray overcooked meat - I don't know any reason to want that. If you want the meat that temp, then better to cook at that temp and let it go all the way through.

Technically speaking, the 2005 FDA food code gives you an allotment of 4 hours total time in the "danger zone" between 40F/4C and 140F/60C. This rule is very crude and imprecise, but that is the standard. Personally I would not push the outer limit of 4 hours at 95F to 105F since that is the temp when bacteria grow the fastest. But according to the official rule, you should be OK. The principle danger in a situation like this is Clostridium perfringens, a anerobic bacterium that has spores that could survive the initial heating, then germinate and grow, producing bacterial toxins and food poisoning. This has occurred, for example in commercial ham production, and/or in turkeys that are roasted then left out to very slowly cool. However that would take longer than an hour to occur, hence the 4-hour rule.

There is basically no agreement whatsoever between various cooking "authorities" on what temperature corresponds to the subjective scale from "rare" to "well done". For me rare in red meat is 120F/49F, medium rare is 130F/55C, 140F/60C is medium. But you can find books that say that 140F is rare! Part of the problem is that temperature alone does not determine things like how red the meat looks (oxygen access matters, for example). Collagen denaturing to gelatin is occurs throughout the whole temperature range, but is much faster at higher temperatures. With SV it is possible to have something cooked medium rare, yet cooked for long enough for the collagen to denature. This doesn't happen with conventional braising.

Well, I am not exactly a mutton specialist! I've never cooked mutton SV, at least so far. The classic thing to do with mutton is to cook it to death - meaning braise for a long period of time to to get very tender, grey meat with a texture similar to other long-braised (osso bucco) or confit cooked meat. Part of the reason to do this is to tenderize the meat, which can be tough, but part of the reason is that most old-time traditional recipes cooked meat to death. To get this effect you would cook at roughly 80C (or 76C if you prefer - the exact temperture is not critical but something at above 75C) for 12 hours. If you want confit like texture put some oil in the bag. If you cook at 55C to 60C, you will get a less-cooked-to-death texture, but you will need to cook much longer to get it tender. 24 hours at least, and it could easily take 36 or even 48 hours. I have cooked some tough beef cuts up to 96 hours. The lower temperture will eventually convert colagen to gelatine and this is an important aspect of tedenization. However, tenderization is not the only reason to braise meat at high temp - if you do pork shoulder or other fatty cuts one can cook them at 55C, and get them tender, but the fat does not render at that temperature, which can be a bit of a surprise. I don't know to what extent that is a problem with your mutton. I don't know how tough the mutton is, so it is pretty hard to say what you should do here. One approach is to throw it in for a period, take it out, test it, and if it is not to your liking put it back in for a while. There is no reason you can't rebag and cook sous vide. Obviously this wouldn't work if you are planning it for a dinner party. Good luck, and by all means post your results so we can all learn from them!

I have a lot of SV equipment! Many water baths - both immersion circulators and integral baths. I also use Rational combi-ovens to use low temperature steam for SV. I have a couple vacuum packers, but my current favorite is Henkelman (a Dutch company that is not distributed very much in the US). I recently got one of the Auber Instruments units to test, and it seems very useful for an inexpensive approach to SV. I also have a couple smokers and a lot of other kitchen equipment.

There is evidence that smoke does not adhere well, or penetrate properly if the meat is cooked (proteins denatured) so most of the flavor enhancement occurs early in the smoking process. This means you are better off smoking first, then doing sous vide. I have done this on many things, and it works well. First you smoke, in order to season with smoke taste, then you sous vide to get tender texture.

Yes, this is all characteristic of SV. Low temperture SV, even for 36 hours, is not going to give you a classic braise texture. If you want that, you need to use traditional braising temperatures - 170F/77C to 190F/88C. Low temperatures - say 130F/54C in tender meat will be medium rare - like a steak or roast. Tender cuts (say a fillet mignon) cooked for a short time (long enough to bring it to temperture) will have at texture exactly like conventional cooking (but with less gray overcooked meat at the edges). A tender cut cooked for a couple hours SV will be more tender than that, but still similar to conventional cooking. If you cook a tough cut of meat at 130F for long enough - say 36 hours (I have done up to 72 hours on very tough cuts of meat) then you a unique texture - medium rare color and taste, and a tenderized texture that is not the same as a conventional cooking, nor is it like a braise. Wine or other seasons in the bag can be overpowering - when the meat is in the bag there is no place else for the flavors to go, so they tend to affect the meat more. In conventional cooking the flavors often evaporate into the air (which is why it smells good in the kitchen).

So, here is the story. FDA rules say the lowest you can do to sterilize (i.e. kill pathogens) is 130F, for times given by tables elsewhere in the post (the FDA tables, not my timing tables). But basically 90 minutes at 130F is considered safe by FDA. FDA says you can be below 130F for no more than 4 hours. So, technically speaking the FDA rules are OK with up to 4 hours at < 130F, but no more. This is a guideline of course - it is a rule that is sometimes excessive, but sometimes not. So, if you want to follow the FDA rules, then no more than 4 hours between refrigerator and done if less than 130F. Or, 130F for 90 minutes or MORE. Does that mean that if you do 122F for 5 hours you will get sick? Probably not, but it is technically outside the rules. Doing 120F for a really long time could be a problem however

Exactly....

Sorry, but I don't have tables for going from frozen. I will try to do this for my cookbook, but don't have it now. 41F was an arbitrary choice - it was close to what my refriderator at the time did, and 5C is pretty standard temp. In reality the tables are about the temperature difference. So the time to go from 41F to 140F, with a bath temp at 141F, is going to be the same as the time to go from 51F to 150F, with bath temp of 151F. As long as you stay away from phase changes (freezing and boiling) then you can scale the tempertures. In the tables, bath is ALWAYS warmer than the final temperature, however in the tables some of the choices are only 1 degree F warmer. So it will continue to rise slightly for a while. If you are cooking within 1 degree of final temperature, the rest time is pretty much irrelevant. If instead, you cook in a bath at a warmer temperture - for example you cook in a 65C / 149F bath and you want to cook to a final temperture of 130F, then the rest itme is a serious issue - the temperture will rise after you take it out of the bath. For example, if you cook a 6 inch thick roast in a 149F bath, and want the core temp to be 130F, the fact is that you must pull the roast out of the bath when the core reads 122F, and it will take about any hour before the core drifts up to 130F. However, I recommend cooking in a bath temp that is only a tiny amount above the desired final temperture. At the time I made the tables various people (such as Joan Roca) were advocating higher bath temperatures, which is why I made the tables include these cases. Since then I have pretty much moved away from using bath temps higher than the desired core temperture (with a couple exceptions). All of this will be discussed better in my cookbook, when it eventually gets done. Nathan