nathanm
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PedroG, blackp, and I have been debating this issue extensively off-list over the last several weeks, and together we proposed an experiment along the lines above.
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Then once we can answer that question, we can go on to explore the vacuum variables involved in long term frozen storage-- hard vacuum vs. 90% vs. 80%; and then the even harder issue of whether to use modified atmospheric packaging (MAP), with either nitrogen or CO2. To that end, I'm probable going to add the gas port adapter to my MVS-31X, and start with a pure CO2 mixture. CO2 plus water yields carbonic acid, which might increase the Ph enough to provide a bacteriostatic benefit, as has been reported with chicken in industrial practice
Hopefully there will be a sufficient number of users on this list with the kind of high-end equipment required to do these tests, as it's now apparent that a single user's tests may not be conclusive, due to equipment parameters and god knows what else.
Bob
There is not that much difference in vaccum settings for most situations.
First off, you will never get a very strong vaccum no matter what you do, because the water in the food will evaporate. With any fresh meat or vegetable you can NEVER have a vacuum less than the vapor pressure of water, since you have water in the food. Note that even if the water in bag does not boil, it is nontheless evaporating.
A chamber style machine can draw enough of a vacuum to boil ice water, but there is little point in doing that. In general you want to draw enough of a vacuum to remove the residual air, but since you will never remove all of the water vapor, there is no point in attempting to pull a vacuum stronger than it takes to boil the water. You don't even need to go that far, but certainly there is no point in going farther.
Note that many vacuum sealers have a default program where they take the bag to 99% vacuum then hold it there for 5 to 10 seconds. The reason is NOT to draw the vacuum below 99%. In fact, depending on the temperature of the food it may not even reach 99%. The goal is to bring the bag to the point where the water in the food will boil. This fills the chamber with water vapor, which helps displace the residual air.
Note that a bit of boiling of water in the food like this is not going to hurt things.
Also, note that you are going to cook the food! Which means that ultimately the pressure in the bag is the vapor pressure of water at the cooking temperature. The original pressure in the bag is pretty much irrelevant.
As an example, if you cook at 60C/140F, then the vapor pressure of water is 19.9 kPa. Normal atmospheric pressure is 101.325 kPa. Vapor pressure of water at 5C/41F is 0.9 kPa.
So if you pack some chicken breasts (or other meat, seafood, vegetables) at 5C (typical refriderator temp), then no matter how hard the vacuum pump pulls, you will never get below a vacuum of 99.1% because that the level at which the ambient pressure equals the vapor pressure so the water boils. Realistically, you can draw a 99.0% vacuum but no more than that.
That will evacuate most of the air and thus oxygen, which is your real goal with sous vide vacuum packing anyway. The goal isn't the degree of vacuum, it is getting the oxygen out, and even then you ONLY care about the oxygen in some cases. If you are serving the food immediately and not storing it in the bag then you don't really care about the vacuum level. In fact, you can cook in an unsealed bag.
We seal and vacuum pack for storage, and a bit for convienence (keeps bags from floating...)
OK, so back to the example. If you pull a 99% vacuum at 5C, then seal it, the food bag is now at atmospheric pressure, because the bag is not strong enough to resist the pressure. In most normal cases with soft food, the bag does not contain a vacuum, and it is NOT "under pressure", despite the title of Thomas Keller's book on sous vide. Yes, it is true that atmospheric pressure pushes on the bag, but the atmosphere pushes on everything, so that doesn't count for anything meaningful.
The only real difference is that if you have a hollow space inside the food - a bubble or cavity - then in the atmosphere that cavity pushes back with the same atmospheric pressure. So, if you vacuum pack, you take that pressure out of the cavity, and it tends to collapse. Hollow foods - say a green pepper - will collapse in the vacuum bag. Stronger hollow foods - say a quail or cornish game hen - sealed in a vacuum bag are generally strong enough to resist the atmospheric pressure, so in that hollow space there will be a partial vacuum.
If you looked closely you would find that the bag has a small amount of gas in it - which is the residual air, and a small amount of water vapor. This is particularly true if the food has a hollow space, but it is even true for a soft food.
When you heat that bag up to 60C the residual air will expand a bit, and more water vapor will evaporate.
In fact, the amount of air and water vapor would be the same as if you vacuum packed the food at 60C temp, at which point you would get about an 80% vacuum.
Now, it is not true that you get a "80% vacuum in the bag" because for most foods there never is a vacuum in the bag once it is sealed. For a soft food, the amount of residual gas in the bag would be identical to one sealed at 60C, at which point the lowest possible vacuum in the chamber would be 80%. For a hard food with a hollow space in the middle, that hollow space would have a parial vacuum of 80%.
If instead you sealed at 90% vacuum at 5C, then heated the sealed bag up to 60C, the amount of residual gas would be a bit more - equivalent to sealing at 68% vacuum.
So, as you can see, there is not that much difference.
Some people, like Dave Arnold, say that they get big differences in results by their vacuum level. I totally respect Dave and his team, and we use many of their discoveries in MC, but I am not sure how to respond to this. In our tests we don't see a difference in the final quality. As the example shows the laws of physics pretty strongly suggest that there can't be much of a difference. My guess (but only that) is that there are some other issues at play here in how the food is handled, but I don't know for sure.
Fish are a particularly amusing example. It is often claimed that fish "can't take the extra pressure" of high vacuum packing.
First off, at a normal cooking temperature, there is very little difference in the amount of air in the bag. Fish don't typically have hollow spaces in them, so this is a moot point.
One reason that fish typically don't have hollow spaces is that fish can generally swim pretty deep. Almost any fish can swim 33 feet (10 meters) deep, at which point the fish is under TWICE atmospheric pressure. At 66 feet / 20meters it is 3 atmospheres and so forth.
Deep dwelling fish, like a monkfish live routinely in a 10-20 atmospheres of pressure.
So, fish, all of animals, are built to take a lot of hydrostatic pressure, and thus should not have a sous vide pressure effect.
Finally, note that "bag pinch" where you can see where the bag came together can affect any food, but that little bag seam is not generally a quality problem.
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I've tried corn on the cob SV, but to me, the long cooking time (1 hours at 85C) tends to make the corm taste too "cobby" for my taste. Nathanm, Thomas Keller, and others recommend slicing the kernels off of the cob, and cooking them with butter and other spices as desired -- perhaps my favorite, a little chipotle and lime.
Don't go so hot! With fresh sweet corn 140F/60C is great. I typically do 30 min for corn on the cob, less if it is off the cob in a thin layer in a sous vide bag.
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After reading the infusing/extracting section in vol.2, I'm wondering if I might be able to infuse flavors into cocoa butter for flavoring chocolate. I'm wondering if there would be any foreseeable problems using sous-vide, but not an ultrasonic bath (since I don't have one!)
Should work fine for any fat soluble flavor.
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Question regarding the pasteurization of meats.
Repeatedly in volume 1 the authors detail the the inside of whole cuts of meat are sterile unless they've been jaccarded. The discussion of salmonella on chicken details that there are 2 "varieties" one that is fecal based and one that invades the ovaries and then the eggs.
Based on this, one would be led to believe that the inside of a chicken breast is sterile like other solid muscles.
If that is the case, why does the whole chicken breast have to be brought to temperature and held for pasteurization rather than just the surface, as one would be able to do for beef? The case is made that it's because chicken is often sold whole with skin on which would carry the majority of the risk, but that would still only affect the surface of the chicken breasts, would it not?
This is substantially correct.
Food safety is about paranoia - as it should be. What you want is measured and appropriate levels of paranoia, but that is not always what you get. The theory behind cooking a chicken breast all the way through is that it would not be hard for contamination to get inside - for example a stray cut with a knife, or even the act of poking a thermometer probe. That is a possibility, and that is the justification for cooking all the way through.
Frankly, most home chefs given a badly contaminated chicken to cook would likely cross contaminate everything else in their kitchen. If you are making a salad in the same kitchen as the chicken, cross contamination could occur, so why not pasteurize the salad?
Indeed, why not pressure cook all food to 12D sterilization, wouldn't that be safer? In fact you can achieve that by only eating canned food - wouldn't that be best of all?
Actually, it would from a pure food safety point of view but most people would say that is silly. Deciding exactly where to draw the line on food safety versus food enjoyment is a judgment call. Most food safety rules are repeated as if they were the pronouncements from on high, and don't admit that they are judgement calls as to a subjective level of risk and reward.
Chicken sashimi (toriwasa) is served in Japan. You need to be very sure of your source of chicken, and clean the outside well, but people have eaten it for years.
In practice it is not that difficult or onerous to cook chicken breast all the way through to pasteurization, so you might as well do it. It probably is safer, although exactly how much safer is open to debate - it depends on your source of chicken. Nobody has good statistics as to how likely it is that you would get sick if you didn't cook all the way through, but wouldn't get sick if you had cooked it - cross contamination and other issues make this very hard to assess.
In other cases - like a green salad - it would certainly be safer to cook it, but that would also ruin it so most people would make the choice to eat their salad raw.
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Time magazine named Modernist Cuisine to their list of the 100 most influential things in the world. The relevant portion of the list shows that MC is only two below "boobs" and above Groupon or Kate Middleton's dress.
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Any chance that second printing kitchen manuals will be available for purchase without the rest of the book?
No plans for that at the moment.
I think that selling the KM without the rest of the book would encourage people to just buy the KM which is not something that I support - I think that the knowledge in the main book is very useful. One could try to have a KM exchange program but that requires lots of logistic hassle which we are not staffed to do.
An additional reason why not is that we are creating a detailed index for the kitchen manual, which we will put online as a printable PDF. We will also include the index with the KM in a future printing, but not the second printing since that is already in press, and we couldn't get the index done in time. So even if I did want to sell an improved KM then I would wait for the one with the index.
Since we are putting PDFs of errata and the index online so you can print them, I think that will at least allow anybody with a current KM to get most of the benefits of the corrections and upgraded index.
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I was curious about the broiler rule of thumb when I read it too. The thing that I couldn’t understand was how the distance from the heating rods to the top of the oven was not a variable. I modeled the system myself and found that under my assumptions* this distance mattered. I also couldn’t come up with a good explanation for the 44% of spacing plus 5mm rule.
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Now if we account for reflection from the top of the oven, things change a bit. Now we get more infrared hitting the food in between the rods but less directly below them due the shading effect MC describes. This is shown in the following graph, which models a reflective oven top 3cm above the rods.
So what does all this tell us about the so-called sweet spot? First of all, as MC tells us, we can’t put the food too close or we get big spikes that will burn the food before it cooks in other areas. The top few curves clearly demonstrate this. But even these curves show shade effects directly below the rods. There are also second-order shade effects where the reflected heat from one rod is shaded by an adjacent rod, but they are smaller and I did not model them. Further from the rods, the curves are smoother and flatter, but still have the shade effects on the order of 15%. The good news is they are quite narrow, so you can cut the effects in half simply by sliding your food to the left or right a couple of centimeters halfway through the cooking. Do this three or four times during the cooking, always in the same direction, and the shade effect should be effectively eliminated.
I'd love to hear how the MC rule of thumb was derived and what assumptions were made. Also happy to hear feedback on my results.
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*My assumptions are that the heating rods are long enough and the food is sufficiently far from the end that their infrared radiation can be modeled by a 1/r rule and that the top of the oven is completely reflective in the infrared part of the spectrum.
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My calculations were done with a full 3D model using (1/r)^2 fall off. Your results should be valid near the center of very large grill - i.e. where the rods are very long. In my case I did the calculation at the centerline, but took into account the finite size of the broiler directly. I also modeled dirtier reflectors (85% reflectivity not 100%).
Yes, the distance between the rods and the reflectors matters, but not very much.
The way I derived the rule is that I did the calculations for literally thousands of different grill configurations and then plotted them up. To my suprise there was a pretty simple correlation which is the rule that we discuss in the text.
Note that this depends on rod diameter as well, but most broilers are fairly similar. Sometimes they use a coil of fairly fine wire instead of a thick rod, but those are quite similar.
Please note that this is just a rule of thumb. Real examples have lots of unique differences - one post above mentions unevenly spaced rods. My own Sodir broiler has a shiny back plate on one side and open on the other three - that changes things there. Putting up your own aluminum foil coller around a dish improves eveness by reflection - that makes a bigger difference than being at the exact sweet spot with respect to rod shading.
Rod shading is one effect, but the fall off near the edge is in general a much bigger effect - that is why the aluminum collar is a good idea.
The sweet spot will by necessity be at a place where the broiler is VERY intense. It's at the point where the reflected light from the top is just about as bright as the light from the rod itself, which puts it very near the rods. So even though this is where things are the most even, you may not be comfortable cooking at that intensity level. As another post mentions, your broiler may make it awkward to actually broil that close, or to see what you are doing. Visual inspection is important with a broiler, so cooking in a matter where you can't see what you are doing may be more even, but nonetheless is harder to do.
I think that the main point here is to alert people to the fact that broilers are not very even in their heat. The fall off at the sides is substantial (unless you have shiny walls, or the aluminum foil coller). Also, it is counterintuitive, but the rods actually do shade the food, giving rise to the funny peaks you found.
Here is a graph of absolute intensity for a 4 bar grill (like my Sodir). Only half of the grill is shown, because it is symmetric around the center. Distance from center is in meters - I probably should have normalized it also, but didn't.
Each line shows the cooking intensity at a different distance from the rods.
If we care about even heating rather than the absolute amount of heat, then we can compare them by normalizing to the center intensity. That gives us this graph.
You can see the bumps, the shading and the edge effects. If you want no more than 10% difference from center to edge then look at the bands between 1.0 and .9 intensity.
The "most even" cooking distance is shown here as the purple line that stays very close to 1.0 intensity, but eventually falls off and hits the 0.9 intensity curve much further to the right than then dense pack of lines below it. It is within 10% of center intensity almost to the point below the outermost rod. The dense pack of lines is only within 10% of being even to just past the center between the two rods - and they are 20% down from the center at the same point where the most even cooking distance is only down by 10%.
Most people broil in the region shown by the dense pack of lines. It is not as even from center to edge, but the intensity is lower, and other practical considerations like being able to watch the food, are more important than the actual radiative intensity.
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We've tried to make the book as good as we could. The fact is that all cookbooks have errors, but I am not aware of any cookbook that has taken the full transparency stance that we have - telling everybody about the errors, providing an errata PDF, and correcting the errors in the second printing.
In fact, I will tell you a secret - many of our errors came because of proofing! It is very easy for a proofreader to find an "error" that isn't actually wrong. One classic example is the difference between converting an absolute temperature between Fahrenheit and Celsius (1C = 33.8F), versus converting a temperature difference ("increase the temperature by 1C = 1.8F). At some point in the process it is hard to add more review without having the review contribute some errors.
It is very easy to say that we should have found all the errors. Of course we "should" have, in some sense, but realistically speaking if you produce a brand new 2400 page, 1500 recipe cookbook, there will be a few errors. It is also easy to say that "for the price" we should have done better, except that prolonged futher review would only make the book even more expensive to produce. You can say that we "should have" looked even harder at the proofs - but I assure you we did look at the proofs very intensively.
Of course you wouldn't even know the number if we hadn't published the list. So I agree with a previous post that by being open we are exposing ourselves to criticism. That's why most book authors don't publicize their errors. It's a classic case of "no good deed ever goes unpunished". The more this occurs, the less incentive an author has to be open and transparent.
But so be it, we remain committeed to being open about this. We have fixed a lot of errors which will be in the first printing, but they will not appear in the the second printing. I am sure that we will find additional errors over time and as we do we will update the web site and the errata PDF, and update future printings.
By printing out the errata PDF, or using pasted in labels (as one post suggests) you can get access to our best knowledge at any point in time.
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Anyone calculate the "sweet spot" of their broiler, per pages 2-22 and 2-23?
I just did, and there's a few issues.
First off, the rods in my electric oven are not evenly spaced; the element consists of 3 U-shaped rods, making 6 straight rods, and the middle one is slightly bigger than the 2 on each side, so my rods range from about 4.5 cm from each other to about 6.5 cm.
That gives me a "sweet spot" that ranges from about 2.5 cm - 3.25 cm from the rods. That's an inch to an inch and a quarter for us metric-challenged people.
That's a LOT closer to the element than I've been broiling at. I'm not even sure if I'm steady-handed enough to get something like a pizza in the oven if I've only got an inch to do it in. And it's confounded by the fact that the element is set in a metal support that hangs down about a quarter inch below the elements.
In order to really broil in the sweet spot, I'd almost have to come up with some sort of system to raise and lower the rack so that I could put the food on the rack, then raise it to the right level. Hmmm.....
The quoted formula is where you will get the greatest degree of evenness, however it is intense enough that this does not mean you necessarily need to cook there. If it is awkward, then cook farther away.
Also, if your rods are not evenly spaced there is not much that you can do to make it perfectly even anyway, so cook where you think it will work best.
Putting aluminum foil mirrors at the sides of the area where you broil will help evenness.
A commercial electric broiler (aka salamander) usually has the rods ride in a housing which can be raised or lowered
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The first curry recipe on page 225 of the Kitchen Manual calls for a tomato puree and references one on page 55 of the same manual. I am not finding that recipe anywhere even doing a search of the full index to MC and the table of contents of the Kitchen Manual. Is it my eyesight or my search skills? I have reported it to the MC team but wonder if I am somehow missing something that is in clear sight. I can easily make a tomato puree but this is really starting to aggravate me. Anyone?
I don't have the kichen manual handy - in fact, I don't have my own copy of the book yet!
But if you look at Volume 5, the curry recipes (page 5.89) refer to a tomato puree on 3.290. That is probably it.
If you look at 3.290 you find a parametric recipe that calls for making tomato puree by cooking peeled seeded tomatoes cut into quarters and cored, and cooking at 85C/185F for 25 minutes.
I don't have the KM to look at, but my guess is that it is referring to a parametric recipe on vegetable purees. Is that what is on page 55 of KM? That would be my bet. If so then the reason you can't find it is that it is not a recipe per se it is an entry in a parametric recipe table.
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Oh: I'm also going to make the pastrami this week (though I'm using brisket, you can't get beef cheeks around here): what is the difference between "red pepper flakes" and "chili flakes"?
Short ribs are our favorite cut for this
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Hi everyone,
I just spoke to a high up manager at Barnes and Noble (who is personally handling all the Modernist Cuisine orders). He informed me that to date, they have not received a single copy of Modernist Cuisine at any of there warehouses. This seems very strange to me since the first printing was supposed to be prorated for the different retailers. Unfortunately, this means that even though I placed my order many months ago, I will likely have to wait till at least July for my copy
.This is just flat out wrong. B&N has recieved many copies. I don't know about their internal systems, but they have recieved many of them.
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We have a policy in the book of mentioning exact brand names we used in case it matters.
In many cases there are multiple grades of what is ostensibly the "same" product. This is particularly true for hydrocolloids. As an example, agar is available in many grades from food ingredient manufacturers. You can also buy agar at the supermarket, and at Asian markets. They are all similar at some level but can have very different properties. It's a bit like calling for "beef" in a recipe when different cuts all have different properties. Fillet mignon is not the same as flank steak.
Different grades of gels won't always work the same. So, if you want to replicate one of our recipes exactly, then use the exact brand we use. Or, try another brand, but be aware that there may be some variation. With a bit of experimentation most other sources can be adapted.
Some products are proprietary blends - as an example Nzorbit is a product of National Starch. It is a type of tapicoa malodextrin, but in that case there are MANY types and you really must use the proprietary product to get the same result. The Texturas line of products, for example, has a gellan blend that is a mix of high acyl and low acyl, so it can't be used to subsitute for pure high or pure low acyl gellan.
That said, you often can subsitute. Nutifos 088 is essentially just pure sodium tripolyphosphate (STPP), so in this case there ought to be very little if any difference between it and other food grade STPP.
Some phosphates are a mixture of STPP and SHMP (sodium hexametaphosphate). In most meat recipes that also ought to work the same way. The only point where I would worry about the composition being critical are in using phosphates for sequestering ions for gelling (see Gels chapter).
So, yes try the substitution. It really ought to work.
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The books will ship to UK customers on Monday, I am told.
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i meant what keeps it from collapsing while pulling the vacuum, and pulling the air out of the jar isntead of it staying in the gel structure
There is lots of pectin in mango, so it will hold all by itself.
Any foam stabilizer (gelatin, xanthan etc) would work for fruit other than mango that does not have the same pectin content.
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I do think it is a little strange that they have you add vodka and don't discuss the reasoning - I assume it's just to extract alcohol soluble flavors, but you think it would be mentioned ? (or maybe I missed it?).
Yes, that is the reason. This is discussed 2.320 to 2.321 and 2.326 - 2.327, but only generically. Sorry about that.
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I will post some photos when I get a chance. I am still traveling - eating at Fat Duck tonight...
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There is a sous vide clotted cream recipe in Modernist Cuisine, but I don't have it handy at the moment.
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OK, so now I have to keep FG honest by relating two of his classic comments during the meal.
We were all mesmerized by the black truffle series. After the braised/raw endive dish (which arrive in transparent packages "en papillote"), there was a pause in the conversation. FG broke the silence with a profound observation "I think that the black truffle really helped that dish".
Reallly? The endive wasn't enough by itself? The rest of us didn't know whether to laugh, or quietly tell the server to stop pouring him wine.
But the classic of the whole evening is when we went back out on the terrace to have petit fours. Thierry Rataureau turnes to FG and says "So, Steven what do you think?" It was Thierry's first time at elBulli and he was contemplating the meal.
FG, who had noticed how little light there was on the terrace turned and said "I think I'm going to need flash".
That's the kind of deep culinary insight that we've all come to expect from him
A great time was had by all of it - it was a great group, and a great meal. It is also the end of a era, which made us all a bit sad, but also happy that we had been there to partake in it.
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I grew up on World Book and National Geographic too... and our editor (Wayt Gibbs) and art director (Mark Clemens) were both from Scientific American.
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Pedro is right - hotter than core cooking requires more precision in timing, for little in the way of benefit.
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When are people without "connections" going to be able to get this book?
I think it important to point out that many peoople who now have this book had no special connections of any kind. They simply pre-ordered from Amazon.
The only connection the people posting here had is that they had followed the progress of the book for 4 years or so on egullet postings so they were able to make a quick decision and order early.
I'm sorry that the book is back ordered - demand has exceeded my expectations. People who ordered by mid-March will get their books in the next couple weeks, if they haven't gotten them already. After some point in mid to late March the orders will be filled from the second printing - those books should arrive to customers by late June.
Note that there is an advantage in ordering sooner rather than later because the 2nd printing will be shipped in stages. The sooner you order, the sooner you get your book. Somebody ordering today may not a book until mid to late July.
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Equilibrium brining
On page 3·154 ff the principle of equilibrium temperature cooking we use in sous vide is applied to brining. In contrast to measuring final core temperature in sous vide cooking with a thermometer, the end point in equilibrium brining can be determined by measuring salinity with an "inexpensive salinity meter". Has anyone tried this? Where did you get a salinity meter? At what price? Can you recommend it?
See Volume 2 page 313 for one type.
Many pH meters will also meausure brine see 2.316
You can also use a refractometer, or a digital dissolved solids meter see 4.366
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Well, I received a notice from Amazon.ca 2 days ago, saying that my book shipped. I was so happy to see the DHL courier walking from his van to my house, until I saw that he was carrying a small box under his arm. The box had only Vol 6, the Kitchen Manual in it. No Vols 1-5! Arghh!
I called Amazon.ca and they surmised that the two parts ship separately. I haven't gotten that sense from reading previous posts. Anyone else have this problem?
They do NOT ship separately. Something very bad happened - like people other than the customer opening the box. The entire set comes in ONE BOX - both the kitchen manual and the 5 hard cover volumes in the acrylic case.
If other people have this happen, please post about it and I will try to find out what is happening.
Sous Vide: Recipes, Techniques & Equipment, 2011
in Cooking
Posted
Sorry, I don't have experience with frozen corn.
I would try it at 60C/140F.
A wild guess is that it will take an hour. I would put it in with an hour (or maybe a bit more to be safe) before the meal, and then test at 30 min and 45 min.