Sous Vide: Recipes, Techniques & Equipment (Part 1)

[pounce]

What a great idea! The main thing that keeps me from making yogurt more often is the hassle of regulating the temperature. Do you vacuum seal the jars?

Nope. I use mason jars and just screw the lids on so they barely seal so they can 'out gas' during incubation. When I take them out I unscrew them a bit to let any pressure out then screw them down tight while they are still warm. I then put them in the sink with icewater. After a while the jar lids will pop and create a good seal. They seem to keep a long time, but not sure how long since I eat them . I was doing yogurt in an electric oven using a light bulb on the end of a dimmer equiped extension cord. I'd put all the jars in a duch oven and fill it with water and then measure the water temp and adjust the dimmer on the light bulb to get the right oven temp. I'd get it right on 109, but it was kind of an ordeal. The water bath solves everything.

Watch the agitiation of the pump. You want to keep the jars still if you like solid yogurt. If you like it smooth then the slight agitation is fine. Mine has a lot of force so I had to adjust it down.

Sorry if this is getting off the topic, but it's nice to know the equipment investment has multiple uses.

I'm not sure how to fit the jars in without completely submerging them. I'll have to come up with a way to try this.

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When I bought mine it came with a small tank, but I have it mounted temporarily on a full size 6" deep steam table pan. I'm going to get one of those hinged lids for the steam pan and cut a hole in one side and mount the unit. When I have a vacuum bag in the pan I have these metal clips from office depot that have big magnets on them. I clip the bag and stick it to the side or the bottom so it doesn't float around.

[Stagiaire]

I'm not sure how to fit the jars in without completely submerging them. I'll have to come up with a way to try this.

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You can always put a smaller pot inside your large pot so that the mason jars are at the right height. Alternatively, you can use those plastic takeout cups they use for soups...just fill them with the same temp water and stack them up until the mason jars are at the right height when you put them on top....

[nathanm]

For some strange reason, after 40 hours, the oxtail still weren't falling off the bone tender. And the veal stock was not gelatinous. The carrots weren't even soft!  As I only had 6 hours left before dinner

I was just wondering how come the meat was still to tough after  40 hours at 141F?  I'm  planning to try it again for up to 72 hours (putting them in several smaller bags and test them at 50 hours, 55 hours, 60 hours and 72 hours. I'm trying to figure out whether it was time or temp that was responsible for the lack of collagen breakdown.

The great thing I noticed though is that the meat kept that medium rare color even after simmering it for 2 hours chilling and reheating them in a sautee pan. It's as if the color had set. Strange, I know, but a happy discovery nonetheless....

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this is not surprising. 141f is low and at this temp it will never be "falling off the bone". it will get very tender, but it will be more like fillet mignon tender than the falling off tender that is typical of meat braised at high temperature. i have cooked tough beef cuts up to 80 hours. eventually you get a mushy sort of tenderness which is not that appealing, but it never gets the way that hot braised meat gets.

the whole issue is whether you want this effect or not. in some cuts it is nearly miraculous - you get medium rare looking meat which has a unique texture that is tender in the sense that you can easily eat it, but it does not fall apart quite like a hot braise would.

note that being "done" is entirely subjective here. you can control very precisely the effect you want to have by choosing the cut of meat, the time and the temp.

if you want a typical hot braise texture you need some heat - less than for conventional, but you need the heat to get that texture. alternatively you can get the medium rare effect, which can be amazingly good, but it is not the familiar braise effect.

the ideal cut for long time low temp sv is one that is tough, but does not have huge amounts of collagen or fat. so, shin / ossobuco / hocks of veal, lamb or other red meats do not do well (my opinion) this way and are better with higher heat. brisket, short ribs, paleron (aka flat iron steak) work very well.

fillet mignon, rack of lamb, or other tender cuts get more tender if held at 130f to 140f for a while, but you need to be careful or you can make them a little mushy.

vegetables are another matter entirely. they need to be cooked fairly hot in order to break down the celluose and other material in cell walls. no amount of time at 141f will do very much for veges. you typically need to be at least 180f and more like 190f to do the cell wall restructing that we expect to soften vegetables.

delicate fruits - like berries - are different of course - there you want to avoid the cellular breakdown so low temps work much better.

[nathanm]

When I have a vacuum bag in the pan I have these metal clips from office depot that have big magnets on them. I clip the bag and stick it to the side or the bottom so it doesn't float around.

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the clips are a great idea!!

[alexw]

For some strange reason, after 40 hours, the oxtail still weren't falling off the bone tender. And the veal stock was not gelatinous. The carrots weren't even soft!  As I only had 6 hours left before dinner, I decided to take them out of the bag and finish them for an hour or two simmering in a Staub cocotte. Came out excellent at the end of the day (they were picked; mixed with some of the gelatinized stock, some chopped parsley, brunoise of leeks, carrots, turnips and truffles; rolled in plastic wrap and cooled; later on sliced inch thick, dabbed with some mustard on one side and dredged in seasoned panko; heated through  in some duckfat, breaded side down and served atop truffled pommes puree)

I was just wondering how come the meat was still to tough after  40 hours at 141F?  I'm  planning to try it again for up to 72 hours (putting them in several smaller bags and test them at 50 hours, 55 hours, 60 hours and 72 hours. I'm trying to figure out whether it was time or temp that was responsible for the lack of collagen breakdown.

The great thing I noticed though is that the meat kept that medium rare color even after simmering it for 2 hours chilling and reheating them in a sautee pan. It's as if the color had set. Strange, I know, but a happy discovery nonetheless....

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what I tend to do with braises, is to perform a standard recipe, and chill quickly, then transfer portion by portion into separate bags, with sauce. then keep this aside for service, then it's just a case of simmer in the bag, which retains juices aromas etc, I have only cooked the more lean cuts low temp (except for a piece of skirt steak once whih was quite frankly vomit enducing).

[pounce]

There are oxidation reactions within biological chemicals in the meat - not from the oxygen in the air, which I agree mostly excluded, but each other. I'm sure the fat will also slowly degrade, although I don't know how fast.

Although the temperature is low enough for the protein not to degrade and the muscle fibres not to contract, eventually the connective collagen turns to gelatine, and the meat falls apart, As I said, the texture reminds me most of meat paste, or perhaps rilletes, except that there are still hard bits (nerves? small blood vessels?) that have not degraded embedded in it.

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I'm wondering if the "mushy" or "meat paste" textures people are expereincing is due to holding meat below the temperature that kills any present enzymes to long thus having the effect of partially liquifying the meat. I wonder what the level of natural (or introduced through processing) enzymes are present in meat that has no extra preperation? I know the meat aging/tenderizing process involved holding the meat at a cool (higher than long term storgage) temperature for between 10 and 28 days to the let the enzymes work on the meat. If we don't raise the temp to the enzyme death zone for long cooking times are we really in effect "cooking with enzymes"? Acids are also a factor so putting an acidic liquid in a bag with meat for a long period of time will likely also effects the texture. Think ceviche.

What do people think?

[edsel]

I'm wondering if the "mushy" or "meat paste" textures people are expereincing is due to holding meat below the temperature that kills any present enzymes to long thus having the effect of partially liquifying the meat. I wonder what the level of natural (or introduced through processing) enzymes are present in meat that has no extra preperation? I know the meat aging/tenderizing process involved holding the meat at a cool (higher than long term storgage) temperature for between 10 and 28 days to the let the enzymes work on the meat. If we don't raise the temp to the enzyme death zone for long cooking times are we really in effect "cooking with enzymes"? Acids are also a factor so putting an acidic liquid in a bag with meat for a long period of time will likely also effects the texture. Think ceviche. ←

I experimented a bit with intentionally keeping the temperature in the range where enzymes are active. Following McGee's discussion of meat enzymes, I tried keeping the temperature just below 40°C (where calpains deactivate) for an hour or so, then ramping up to just below 50°C (at which point the cathepsins become inactive), and then ramping up to a more normal long-cooking temperature (normal for sous vide, that is).

I tried doing this with Moulard duck legs "confit" and with beef brisket. I tried several combinations of ramping times for the duck legs, with subtly different results. The more prolonged the time at lower temperatures, the softer the meat texture. The result was OK, but somehow not exactly "confit-like". Also, the low temperature cooking appears to "set" a pink color in the meat which no amount of further cooking will remove. Some people may find this unappetizing.

The beef brisket was one of the few experiments that ended in utter failure. The flavor was bland and the texture was absolutely revolting. Think of wet papier mâchè and you get the idea. The color was also an unattractive pinkish grey.

[Ana Alfaro]

Hi, I¡m new to this topic. I recently read somebody using sous vide and cryovac as if they were synonimous. It does not sound right, since sous vide only implies a vacuum, and cryovac implies sub-zero temperatures, I believe. Anybody willing to enlighten me?

Regards, Ana

[nathanm]

I experimented a bit with intentionally keeping the temperature in the range where enzymes are active. Following McGee's discussion of meat enzymes, I tried keeping the temperature just below 40°C (where calpains deactivate) for an hour or so, then ramping up to just below 50°C (at which point the cathepsins become inactive), and then ramping up to a more normal long-cooking temperature (normal for sous vide, that is).

I tried doing this with Moulard duck legs "confit" and with beef brisket. I tried several combinations of ramping times for the duck legs, with subtly different results. The more prolonged the time at lower temperatures, the softer the meat texture. The result was OK, but somehow not exactly "confit-like". Also, the low temperature cooking appears to "set" a pink color in the meat which no amount of further cooking will remove. Some people may find this unappetizing.

The beef brisket was one of the few experiments that ended in utter failure. The flavor was bland and the texture was absolutely revolting. Think of wet papier mâchè and you get the idea. The color was also an unattractive pinkish grey.

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This is very interesting. I'm going to try some experiments here also. You could call this "hot aging" of the meat. I have tacitly relied on this in the past via slow normal cooking but haven't tried explicitly holding the meat at low temperatures deliberately.

The thing with confit texture is that it is produced by much higher temperatures and you are just not going to get it any other way. I make confit at 170F to 180F - it just does not have the confit texture otherwise. However, sous vide texture is very good - you just have to consider it a new option rather than a way to achieve an old traditional effect.

[nathanm]

Hi, I¡m new to this topic. I recently read somebody using sous vide and cryovac as if they were synonimous. It does not sound right, since sous vide only implies a vacuum, and cryovac implies sub-zero temperatures, I believe. Anybody willing to enlighten me?

Regards, Ana

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Cryovac is a brand name of vacuum packing equipment (http://www.cryovac.com/). Most of their products are geared toward large scale industrial food packaging. The "cryo" in the name is meant to imply cold because the first application was vacuum packing fresh meat for cold storage. However, you might think that cryo implies frozen or cryogenic - but that is not the case, the bulk of Cryovac's market is fresh rather than frozen. It's a brand name; it does not have to be technically correct.

Virtually all meat in the US, and a lot in Europe, is vacuum packed like this at some stage between slaughter and the final market. Cryovac packaging is usually done in heat shrink bags (also called thermo-retractable bags). You seal in a vacuum chamber, then dunk into 200F boiling water (very briefly) to shrink the bag.

In case you care, here is background on vacuum packing in the meat industry http://meat.tamu.edu/packaging.html Within the meat industry, Cryovac is a leading packaging supplier and pioneered the whole field, so most professional meat people will use the term "cryovac" as the generic name for every vacuum packing system (like people use Kleenex for all kinds of facial tissue).

Sous vide is about cooking in a vacuum packed bag. As such it uses a similar vacuum packaging machine. Typically you use different bags (sous vide requires a bag that can take heat) and usually you don't use heat shrink bags in SV (although there are some applications).

The recent Amanda Hesser article used the term "cryovacking" in the context of sous vide which I guess some people use, but it is technically incorrect and misleading because the meat packing industry already uses the term to mean vacuum packaging without cooking. I think this usage happens because chefs are familiar with the term cryovac from talking to their meat supplier. They even refer to the vacuum packing machine as a "cryovac machine". However, the Cryovac company does not even make the small packaging machines - they are made by Koch Equipment http://www.kochequipment.com/overview/ and distributed by Cryovac (among others). These are sturdy machines, and you find them in some restaurant kitchens. However, they are not as sophisticated as the better European machines that are microprocessor controlled.

I agree that it is confusing and inappropriate to confuse vacuum packing for shipment and cold storage with sous vide which is vacuum packing for cooking. The Cryovac company does NOT promote sous vide cooking at all - if you search their web site there are ZERO mentions of the term. Some of their big industrial systems will package then cook the product in the package, but that is nothing like real sous vide.

So, anyway there is more than you (probably) wanted to know about the relationship between sous vide and cryovac.

[slkinsey]

Thinking about home sous vide cooking with a Tillia III Foodsaver "professional" model. . . has anyone thought about double sealing the bags to prevent some of the ballooning?

A normally sealed Foodsaver bag looks something like this:

I was thinking that, once the bag is sealed and provided that there is no liquid in the large, flat empty part of the bag (freezing the liquids should take care of that), you could place the flat part of the sealed bag on the Foodsaver sealing strip and manually seal the bag again much closer to the food. Then the extra part of the bag could just be cut away (and potentially used for something else). It would look something like this:

That would presumably cut way down on ballooning, and also keep any exuded juices, melted oils, etc. confined to the area with the food rather than potentially migrating to the (inflated) flat part of the bag.

[Msk]

Sam,

Foodsaver also has "Rolls" of bags you can custom cut to your food size. Just be careful you don't cut the bags too close to the food as the seams are more likely to pop open.

Msk

[slkinsey]

Well, right. This I know, of course. But even with custom made bags I have found that it often seems like it would be possible to do a second seal much closer to the food. (My illustrations exaggerate for effect.)

[nathanm]

Many commercial machines are set up to do this - you push the seal bar as close to the food as you can, and then it automatically cuts off the bag just past the seal. You can do the same by cutting the bag short first (just not too short).

The other thing you can do is seal twice a little way apart because that helps have redundancy in case one seal breaks.

[edsel]

The other thing you can do is seal twice a little way apart because that helps have redundancy in case one seal breaks. ←

Yeah, the belt-and-suspenders approach. After my duck fat meltdown episode, I've been known to do that.

I think that what Sam wants to do is cut down on the "bag bloat" effect. I'm not sure how much of a difference it makes whether the seal is close to the product. Some things are just going to inflate the bag no matter what. Broccoli will blow it up like a balloon if you don't par-cook first. I haven't had much trouble with meats picking up air pockets in the bag. Some things give off a lot of liquid, but the air pocket thing seems to be mostly from vegetables giving off gasses as they heat up.

[pounce]

Samuel, I've done exactly as you have illustrated. I'm almost ready to upgrade to a more professional vac machine than the tilla...almost. I make my own bags and find it sort of tedious with the Tilla with it's recommended wait time between seals and the fact that the vac runs whenever you want to make a seal effectively running it 100% more than really needed. I'm looking at buying another item just to seal bags. You can find them everywhere and are used in retail to seal poly bags. Most are called impulse sealers. There are some cheap ones on ebay also. I found some really cheap ones at my favorite cheap tool store Harbor Freight. I'm thinking of getting a 15" model.

Impulse Sealer at Harbor Freight

With something like this I think it would be easier to sculpt your bag size after the initial vac and seal.

For those who don't know costco has a pretty good deal on Tilla bags. There is a box of 4 12" rolls and 2 8" rolls for around $38. I use the sealer for a lot of things other than sous vide hijinks so I'm always looking for a deal on the bags.

Has anyone found good alternatives to the tilla bags for use with the foodsaver?

Edited September 8, 2005 by pounce (log)

[nathanm]

I have an interesting new result to report.

It is well known that one of the reasons that juices escape from meat as it cooks is that fibers in the muscle contract. These contractions squeeze juice from the meat - in effect the meat wrings itself dry. This process starts at 120F/50C when myosin starts to coagualate.

Because the effect depends on temperature, it happens in sous vide cooking in the same way as any other kind of cooking.

I wondered if one could effect that somehow, so I have run a series of experiments where I used a Jaccard meat tenderizer. The Jaccard is a set of 48 thin blades that poke through the meat and cut some of the internal fibers. Running the Jaccard through the meat cuts many (but not all) of the fibers.

Most steakhouses use a Jaccard (or the industrial equivalent) to make certain cuts tender, particularly New York and Rib Eye steaks. Note that the Jaccard does not generally leave any obvious marks on the meat once it has been cooked. People served a Jaccarded steak generally will never know. It tenderizes by cutting enough of the meat fibers to make it much easier to chew, but without getting soggy or mushy.

On one hand, the Jaccard perforates the meat, so one might think that more juice would run out. That is the common sense answer. However, at the same time, the Jaccard cuts fibers that would otherwise pull and squeeze the meat which forces the juice out, so perhaps it would not leak more.

As I guessed, the results of several experiments show that the meat perforated with the Jaccard loses LESS juce than the unperforated meat. The same fiber cutting that the Jaccard does to make the meat tender reduces the ability of the fiber shortening to squeeze juice from the meat.

The effect is pretty large. The un-Jaccarded meat loses about 50% more juice than the one that is Jaccarded.

I have repeated this several times now in different cuts of beef cooked sous vide to 130F/54.4C. Other red meat should be the same. I have not tried poultry or fish yet.

So, if you want a juicy piece of meat, consider using a Jaccard tenderizer first. Yes, I know that sounds strange, but there you have it...

[Silly Disciple]

that's fascinating Nathan.

Can you comment on the resulting texture of one piece of meat vs. the other after cooking sous vide?

[UnConundrum]

Nathanm,

You've been such a great source of information on this subject... Can I impose on you some more? Would you be willing to share your experiences with vacuum sealers?

I'm currently a Foodsaver Pro II user, but I'm ready to move ahead with a more commercial version. This sous vide cooking is extremely intersting to me, and just what I needed to convince me to make the move.... I've never even personally seen a chamber type of vacuum sealer, although I can see the pictures on various web sites... I could probably afford the ARY SVP 10, but wonder if there were other models or features we should look for.

I often use my FoodSaver to seal mason jars filled with spices (they last much, much longer that way). Can you put a mason jar (on its side) into a chamber type of sealer, maybe with the band attached to hold the lid in place, and seal it? Will the chamber hold a mason jar?

[nathanm]

that's fascinating Nathan.

Can you comment on the resulting texture of one piece of meat vs. the other after cooking sous vide?

←

The texture was good on both the Jaccard and non-Jaccard meat. Jaccard is more tender due to the processing, but it does not get mushy unless you cook it for so long that the normal meat is mushy too.

[nathanm]

Vacuum sealers are a big topic if you really get into it. Here are the basics.

First, there are two kinds of machines - edge sealers and chamber machines. Edge sealers grab the edge of the plastic pouch or bag, suck the air out, and then seal it. The bag sits outsides the machine. Chamber machines are much larger because you put the bag completely inside a vacuum chamber in the machine.

The edge sealers include the inexpensive consumer machines like Tilia Food Saver, Rival and a couple others. There are also a couple of more expensive commercial grade edge sealing machines.

Edge seal machines are problematic for sous vide because they tend to suck liquid up into the machine. Nevertheless they are cheap, so a lot of people use them. A good trick for an edge sealing machine is to freeze the liquid into an ice cube so that it can't get sucked out.

As discussed in this thread, a lot of people use edge sealing machines for sous vide because they are widely available and affordable.

Chamber machines are the best way to go for professional results - liquids work fine in them. In fact, I store stock by vacuum sealing it in pouches, then freezing. Chamber machines draw a lower vacuum, have stronger pumps, and are all around a lot more versatile. However, they are also much bigger, heavier and more expensive. Like is like that.

Chamber machines have an interesting tradeoff. The bigger the chamber, the larger the food you can seal. However the flip side is that big chambers take a while to suck the air from, so they can be slower. Typical machines will have a "cycle time" of between 20 seconds and a minute or two. Of course, manufacturers tend to be very optimistic when they quote cycle times - for example by quoting a cycle time with very large things in the chamber (which thus has less air and is faster to pump out).

As the size of the chamber gets bigger you can of course get a bigger vacuum pump. Look carefully at any machine you use and make sure that it has a cycle time that is acceptable. If you seal a large number of single serving pouches this can be an issue.

One approach to getting throughput is to have a dual chamber machine - these let you fill one chamber while the other chamber is being sucked empty. Dual chamber machines are very large and probably only make sense if you are really high volume.

A simpler way to get higher throughput is to choose a machine with a long enough sealing bar that you can do two bags simultaneously. This gets you twice the

I typically use a bag that is about 7 x 10 inches. My chamber machine has a 10.5 inch sealing bar so I can only do one at a time. If I got a machine with a 16 inch sealing bar I could do 2 at a time, doubling the throughput.

Some machines have an option to have dual bars, at either end of the chamber. In that case you seal one, or even two bags on each bar.

American made machines tend to be very basic and lack a lot of the features found in European machines. The most famous brand is Cryovac, and many chefs think that they make vacuum sealing machines.

Well, they don't make small ones. Cryovac primarily sells huge systems for factory scale meat processing. Cryovac does resell the Koch line of smaller machines for chefs

see here, or from Koch directly. The Koch machines are very sturdy but they are primitive compared to the better European machines.

Ary Corporation has two US made machines that are entry level chamber machines - the SVP-10 and SVP-15. I have the latter. The difference between the 10 and 15 is that the 15 has an oil based vacuum pump, which needs to be regularly serviced, but is more powerful than the pump in the SVP-10 which never needs maintenance. If you want the cheapest chamber machine one of these is probably the way to go - they are pretty widely available and are about $1200 to $1500 (see for example here).

Here is another low priced chamber machine, which has a few advanced features.

Koch machines are more like $2500 and up. A good medium sized table top vacuum machine is $3000 to $4000. That sounds expensive (and is) but if you do a lot of sous vide cooking then you have to consider that this in effect replaces a lot of expensive pots and pans. It is also very useful for food storage.

One interesting thing is that Busch, a German company, makes the vacuum pumps used in most machines, regardless of whether the machine itself is assembled in the US or elsewhere. They seem to be the market leader. SVP uses Italian vacuum pumps in the SVP-15.

One feature that you may see advertised on machines is "gas flush". This is a system where you connect the machine to a nitrogen tank (which is inexpensive) and it blows the chamber out with nitrogen prior to pumping down to a vacuum. This helps reduce oyxgen levels in the pouch even further. However, it is mainly useful for storage (i.e. vacuum packing to extend shelf life) rather than for sous vide cooking.

The US machines are primitive compared to the European machines which typically have several additional features. This isn't a question of national chauvinism - sous vide is much more advanced in Europe than the US right now.

Service is always an issue - all things being equal it is better to go with a compnay that has service people (or authorized service shops) in your area. If you rely on a machine crucially for your business, you really don't want it to quit. Home use is generally more forgiving in that way.

The European machines (and a few US models) are typically digital rather than analog, and have microprocessor based controls.

"Soft air" or "soft release" is a very good feature on advanced machines. This is a valve that gradually releases air into the chamber at the end of the sealing cycle.

Soft or delicate foods can be crushed by the rapid influx of air - this is particularly true of something like fois gras which can crack when the vacuum comes back on. It also helps prevent creasing in the bag.

Another feature is double seal bars - this in effect does two independent seals on the bag to make sure that it stays sealed.

They also store 10 or more programs for various food types -so that you can program the vacuum level, seal bar tempertaure, soft air (or not) and other parameters.

Some machines also feature special cycles for achieving extra high vacuum (important sometimes for sous vide, but mainly for storage).

Here are some of these European machines - Henkelman,

Biro (US based reseller of imported machine). Powervac Note that many of these are imported to the US would be available here.

I don't have enough experience to say which of these European machines is "best". Perhaps an eGulleter from Europe can comment.

There are several others - notably some German and Dutch made machines but I don't have the URLs handy.

The more advanced machines naturally carry more advanced pricetags.

I am somewhat feed up with my SVP-15 machine - it is slow and it has a tendency to blow fuses often. So I will probably replace or suplement it with a more advanced machine.

[UnConundrum]

Thanks Nathan,

I think I may stretch the budget and go for the Minipack you so kindly offered a link to. But that page raised another question. They have an option of either 2 4mm seals or one mm seal and a cutoff wire. Would the cutoff wire be used for roll bag applications, not really applicable to sous vide?

[pounce]

Instead of using a table you can use a thermometer probe, inserted though closed cell foam tape. 

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Nathan,

I have to say that I appreciate all of your effort in this thread. You have provided so much useful info.

I'm curious about temperatures and read back to your posts and tables. I have an immersion unit that can be operated by a computer. I can log water temps and contro the temp using some profiles if needed. What I can't do at the moment is log the temp of the item sous vide. I would like to do some experiments and correlate the bath temps with internal temps. I'm curious about your technique with closed cell foam. How does this work exacly? Is this the stuff that has a sticky side? Do you just punch a hole in the bag before vacuum packing and then stick a piece of foam tape over the hole and seal the bag?

I've found a food temperature data logging probe what looks perfect for what I would like to do, but the solution is around $400. See the data logger. The advantage here would be I could seal the probe in the bag and fetch it later. The probe logs data at defined intervals within the unit so you can hook it back up to the computer and correlate the temp data.

What I'm curious about is how temp curves effect the cooking time. I wonder if starting with a cold bath then bringing up to temperature can effect the results in some way. I also wonder if starting at a higher temp and letting the temp drop to the desired temp is avantageous.

Any thoughts?

[UnConundrum]

New article appearing in the Washington Post....

Sous-vide in Washington DC.

[nathanm]

Instead of using a table you can use a thermometer probe, inserted though closed cell foam tape. 

←

I'm curious about temperatures and read back to your posts and tables. I have an immersion unit that can be operated by a computer. I can log water temps and contro the temp using some profiles if needed. What I can't do at the moment is log the temp of the item sous vide. I would like to do some experiments and correlate the bath temps with internal temps. I'm curious about your technique with closed cell foam. How does this work exacly? Is this the stuff that has a sticky side? Do you just punch a hole in the bag before vacuum packing and then stick a piece of foam tape over the hole and seal the bag?

I've found a food temperature data logging probe what looks perfect for what I would like to do, but the solution is around $400. See the data logger. The advantage here would be I could seal the probe in the bag and fetch it later. The probe logs data at defined intervals within the unit so you can hook it back up to the computer and correlate the temp data.

What I'm curious about is how temp curves effect the cooking time. I wonder if starting with a cold bath then bringing up to temperature can effect the results in some way. I also wonder if starting at a higher temp and letting the temp drop to the desired temp is avantageous.

Any thoughts?

←

I have many data loggers, but not that particular one. Data loggers are great for some tasks, but they tend not to have great temperature probes, and as you point out they are expensive.

You want a probe small enough to get to the exact place you want it - in the center of the food typically. I use thin needle probe from thermoworks

These probes are great. You can the use the probe with either a digital thermometer or with a data logging unit for a PC (which is what I do).

To use a probe with sous vide you first seal the food in the bag normally. Then you cut a piece of closed cell foam weatherstripping tape - just a piece 1/2 inch (1 cm) long will do. Yes, the weatherstripping is sticky on one side. You stick that to the bag, then insert the needle probe through the center of the foam tape and into the food. Now you can put the whole thing into a water bath, or steam oven or cook it however. The bag will not lose vacuum unless you pull out the probe.

Ramping the temperature in the water bath will slow down the rate at which heat is conducted into the food. The fastest way to heat the food up is to use a bath at a temperature higher than the final core temperature (but I recommend not much higher). If you start with the water cold, then you'll get much slower heating.

It's not clear why you need to have a slower cooking time. If you want to hold the meat at a particular temperature (to allow enzymes to tenderize the meat) then raise to another temperature, then having a specific ramp might make sense.

One thing to consider if you are using a water bath is that the most laboratory water baths and circulators have pretty low wattage (1000W for most, up to 2000W for others) is not all that high so it can take a while to ramp up from cold.