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

Try the short ribs at 55C for 24-36 hours. You will be amazed.

I will post more tables tonight. Thanks to Dave Scantland (Dave The Cook) for helping fix the formatting problem.

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

Moderator's Note: Please click here to see nathanm's table for 54.4C/130F final core temperature starting at 5C/41F initial temperature.

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

I started this thread nearly a year and a half ago asking about information on Sous Vide, particularly recipes which would give me cooking times and temperatures. Ironically, I am now going to largely answer my own question.

In the intervening period of time I have bought and read every book on SV in English, French and Spanish, talked to chefs, and done countless experiments of my own. Here are my conclusions on the basic issues for time and temperature.

There are several factors that go into determining the cooking temperature and time:

1. Is SV for immediate service, or to cook and hold? SV got its first big push in cooking meals on an industrial scale for later reheating – for example for airline catering, or servicing low to mid range restaurants from a central large scale kitchen. That is the cook and hold method – the food is stored up to three weeks after the SV cooking. More recently SV has been used by high end chefs for immediate service – i.e. just like roasting, frying or other techniques.

2. What is the product? Obviously, fish and meat are cooked to different temperatures, and even within something like beef there is a wide range of temperatures depending on the cut and on personal preference. The main split is pretty simple however. One set of cooking processes occur rapidly, so the goal is to bring the food to a temperature. Another set of cooking processes – such as tenderizing tough meat – require a lot of time. Collagen breaks down into gelatin at or above 130F / 54.4C, but the rate is very slow until you get a higher temperature.

3. Do you need to sterilize / pasteurize? This is a food safety question, but it is not as simple as you make think because most of what chefs are told about food safety is actually wrong. Sterilization means heating the food to a high enough temperature, and leaving it there for a long enough period of time that it kills microorganisms that could be harmful. Sterilization is required by law for some food products but there is no legal requirement for sterilization of many foods. Otherwise we couldn’t have sushi, carpaccio, or even a rare steak. Cook and hold SV requires sterilization no matter what the product is, but that does not necessarily mean you have to cook at high temperatures (see below).

4. Do you want to cook at the final temperature, or above? Conventional cooking is almost always about using a heat source (oven, steam, poaching water) that is much higher temperature than the food. As a result, timing is important. In SV you have the option to cook at, or only slightly above the final temperature. The cooking is very slow, but as a result timing is not critical you can hold the product for a long time without risk of overcooking. Or you can cook at a higher temperature. This has the benefit that the cooking time is shorter (see below) but you can’t help but overcook part of the product, and you must be careful about timing.

The food safety issue is particularly interesting. Most people think this means cooking to 140F / 60C – that is not correct, it is about both time and temperature. 140F/60C is NOT ENOUGH if you do it for a short period of time – typically you need to be at that temperature for at least 12 minutes. Conversely, red meats can be cooked at 130F / 54.4C and be just as sterilized if they are held for 112 min. Poultry is frequently incinerated in a well meaning attempt to meet food safety guidelines, but in fact the US FDA says it is perfectly acceptable to sterilize lean turkey or chicken at 136F/ 57.8C for 64 minutes. These times come from the following FDA document http://www.fsis.usda.gov/OPPDE/rdad/FSISNo...ltry_Tables.pdf

Many people who have the phobia that below 140F/60C is unsafe do not realize this and will say things like “it is unsafe to do long time duration cooking at 130F”. In actual fact it is SAFER than bringing food to 140F, unless you keep it there for 12 minutes. As long as you follow

In addition, it is not necessary to cook all foods to the sterilization limit – the majority of our food is not cooked to that limit even in conventional cuisine. So, most things that are served medium rare or below, including fish, beef, lamb, duck breasts and so forth are not cooked to sterilization normally speaking, and it is not clear why we would have to do so with SV (for immediate service).

Here is what I do.

I almost always cook for immediate service, not cook and hold. Nothing against it, but that isn’t what I do.

I use laboratory water baths for most of my SV cooking, or a Rational combi-oven in steam mode if there is a large quantity.

I almost always use a cooking temperature that is just marginally above the final temperature. This makes cooking times longer, but it gives a better, more uniform result. If necessary I cut the product thinner to achieve reasonable times. Note that this approach is very different than many SV practitioners, such as Joan Roca. His book recommends cooking most food at a temperature substantially above the final internal temperature, although this is not consistent - for some things he recommends cooking at the final temperature.

I cook most fish (including prawns) to 45C / 113F. That is below the sterilization limit. That is perfectly OK within food safety guidelines so long as the cooking time is not too excessive (i.e. so long as it is less that a couple hours). I would NOT cook thick pieces of fish this way because the cooking time would be so long that some spoilage could result.

Beef and other red meat I cook to 130F / 54.4C. This is what I would term “medium rare” but there is a lot of disagreement on mapping subjective terms like that to temperatures. Depending on the situation I might cook it to sterilization, or I might not.

Tough red meat – such as flat iron steak, short ribs etc I will cook at either 130F/54.4C or 136F/58.8C, from 24 to 72 hours depending on the cut and how tough it is. This gives time for the collagen to break down and make a tender result.

Tender cuts of pork, such as tenderloin I generally cook to 140F/60C. Trichinosis is killed at 137F, and anyway has been eliminated from the food supply in the US and many other places. I would cook wild meat a bit more, and/or pre-freeze it.

Chicken and turkey also gets cooked to 140F, and I make sure that I follow the sterilization times.

Duck breast goes to 130F/54.4C. Duck confit is 180F/82.2C for 8-12 hours – pork or lamb confit is the same.

OK, so given all that the only remaining question is how long to cook a given piece of food. The answer is that it depends on one thing – the thickness of what you are cooking. Heat slowly diffuses through a piece of meat or other food product. The time it takes depends on the thickness and is very nonlinear – i.e. doubling the thickness more than doubles the cooking time.

In a flat slab, such as a steak or cutlet, the relevant thing is the thickness. In a more irregular shaped thing, such a chicken breast or a whole chicken, the cooking time is going to be constrained by the thickest part.

This is true for any kind of cooking actually. Most of what we are taught about cooking is actually wrong. For example, anytime somebody tells you it is “10 minutes per pound” they are saying something that cannot possibly be accurate, because this would imply that cooking time is proportional to the weight. If you take something like a whole bird and scale it up you will find that cooking time is actually proportional to something like (weight)^(2/3) – weight to the 2/3 power. This is because increasing the weight scales up the thickness by the cube root. Since most people are not accustomed to taking things to fractional powers, people substitute a linear relationship. That might work out OK in practice over a small range, but it can’t be accurate over a large range. For example, if you double the weight, the linear relationship would tell you that you double the cooking time. The 2/3 power would tell you to increase it by 59% - that is a pretty big difference.

As a general rule of thumb heat diffusion times go as the square of the thickness increase. So, doubling the thickness results in FOUR TIMES the cooking time. That is a rough general rule of thumb, which is not perfect but it illustrates the nonlinearity of the system. I don’t know why this isn’t taught to chefs more often because it is a fairly easy thing to grasp and use.

A more accurate way is to compile a table of times and thicknesses. I have done lots of experiments, and I have also written some software to solve the partial differential equations governing heat flow. The theoretical results agree with the experiments to extraordinary precision – a tiny fraction of a degree, and/or a tiny fraction of a second. The result of all of this is that I have produced the following set of tables.

Instead of using a table you can use a thermometer probe, inserted though closed cell foam tape. However, it is still useful to have the cooking times so you can plan ahead and know roughly how long things will take.

In each case I list different options of thickness, and different cooking temperatures. I use the low temperatures, but I have included the result for using higher temperatures, for example as recommended by Joan Roca in his book. I have also listed the time difference required to reach one degree less, or one degree more – i.e. it is the time range between undercooking or overcooking by 1 degree C (1.8 degrees F). This gives you the margin of error that you have in the timing. If the cooking temperature is the same as the final temperature, you can’t overcook it, so that is infinite.

Note that the thermal diffusivity of various forms of animal flesh (chicken, meat, fish) is very similar so within the accuracy displayed here, the product type does not affect the cooking times.

I will start with the table for a final core temperature of 54.4C / 130F. I’ll put other tables in other posts.

The first column is the cooking temperature (water bath or steam oven) in degrees C, the second is degrees F. The next column is the thickness of the slab in mm, followed by the thickness in inches. Then comes the cooking time, and the resting time. The resting time as I use it here means the time until the core temperature stops rising and starts to fall. The next two columns are the core temperature at the time you stop cooking, in C and F. Even if you use a digital thermometer probe, you can’t just wait until the food is at the final temperature, because if you do it will overshoot. The overshoot is minimal or non-existent if the bath temperature is close to the final temperature. However, the higher you go, the more the risk of overshoot.

Finally I have two columns showing the cooking time to go one degree C lower, and one degree C higher. This shows the amount of time latitude you have. In some cases it is quite surprising – a multi-hour cook time might only have 5 minutes plus or minus leeway.

It turns out that it is easier to get the HTML formatting correct if I put the table in a post by itself, so it comes next.

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

I have been meaning to post about temperature sensing through the bag. As the post above says, you can monitor temperatures inside the food during sous vide cooking.

First, buy some foam tape weatherstripping. BUT PLEASE NOTE you want CLOSED CELL FOAM. There are two kinds of foam tape! The open cell type is not going to do you any good at all, so get closed cell foam. It usually says the type on the package.

I generally get the 1/4" (6 mm) wide weather stripping because I use thin needle probes, but you can use 1/2" (12 mm) if you want.

You cut a small square of the weatherstripping and stick it to the bag. Then take a sharp temperature probe and stick it through the foam and into the food. The bag should not leak, and will maintain vacuum.

I use the "minature needle probe" from Thermoworks but others will work.

You connect the probe up to a digital thermometer. There are many makes and brands. My favorite one for most cooking use is by Extech, because you can set an alarm for it to beep when it hits a certain temperature. That is very handy because it can take a long time and you don't want to be watching the thing. Any thermocouple based digital thermometer will do.

Once the probe is in the food, you can put the whole thing into either a waterbath or a steam oven to cook. The probe wires are fine, and the bag won't leak - or anyway it hasn't happened with me, even for cooking times of many hours.

Obviously, if you are cooking many items, pick one that is the thickest to put the probe in because it will be done last.

Note that when you pull the probe out at the end of cooking time, the bag will lose vacuum. So, if you are not going to use it immediatley, it will NOT keep like a regular sous vide bag would. You can simply put the bag in another bag and reseal, or use it immediately.

The main use of the probe is to establish the cooking time. Once you have it set, you don't need to do this every single time if you have identically sized product.

I am in the process of generating a table of cooking times for different products at various temperatures - when I get this done I'll post it if there is interest.

[Smoking and Barbequing Meat]

As I said in the original post, I have great respect for "seat of the pants" barbeque. There is no disrepect to this approach in wanting to learn more, nor does it take anything away from that to actually find out how it works. If you want to still make barbeque your way, nobody will stop you - certainly not me.

[Smoking and Barbequing Meat]

Like I said, there are many strong opinions, often contradictory

While one can cook by the seat of the pants and get great results and then have chocolate ice box pie for dessert. Be my guest.

However I like to understand more about the process. Sometimes that means using sensors and transducers and so forth. The knowledeg that is learned that way can have a lot of implications, even for seat of the pants cooking. But anyway, that is what I am interested in.

As to the other post, I don't think that bacteria are responsible for the smoke ring - or anyway I have never heard that, and would be shocked if it was so.

[Smoking and Barbequing Meat]

I have smoked and barbequed meats for many years, and I own, or have owned just about every device mankind has produced for doing this. This includes traditional style barbeque "pits" all the way to computer controlled smokers that control humidity temperature and a dozen other variables.

I don't mean to brag, but I've had some success at this - I've competed several times in barbeque championships, including Memphis in May and the Jack Daniels Invitational. The team I was on (I am not the leader however) has won first place at those competitions.

Along the way I have noticed the following things. First, nearly everybody involved in barbeque or smoking meat has strong opinions. Second, many of those strongly held opnions directly contradict one another! So, one guy will say "never do X", and almost certainly you can find somebody else that says "always do X". They can't both be right.

Often the opinions come with elaborate stories that sound semi-reasonable. However, in most cases these are like Kipling's "Just So" stories (how the leopard got his spots etc.) - they are based on folk wisdom, not reality. A famous example of this is the notion that you must sear meat to "seal in the juices". This makes a certain amount of intuitive sense - it just happens to be completely wrong. Barbeque and smoking are filled with these sort of beliefs, hence the directly contradictory "facts".

I am looking for some definitive answers and hard facts. I know people who are incredible barbeque chefs / pit tenders / smokehouse operators who fly by the seat of their pants. But surely in the 21st century some of these things can be reduced to fact. This is particularly true of parameters that must have been studied to death by food scientists, and the meat processing industry.

Some people viewing this post may question the importance of getting hard facts, because if the seat of the pants method works for you, why worry about things like relative humidity, or optimimum meat temperature? However, we have seen the same tranisiton occur in other forms of cooking as people test old beliefs and discover that many are false. New ideas, new techinques and a better understanding of cooking comes from such knowledge. So, even if you can't adjust your RH or wood temperatuer exactly, I think it is interesting to know what the real truth is.

Here is my initial list of questions to which I think there must be a definitive answer, but where there is seems to be no or little agreement.

In the questions below unless specified "meat" means flesh - i.e. poultry, pork, beef, fish.

1. At what temperature (in the meat) does meat absorb smoke best? One recent barbeque book claims that above 120F proteins in the meat start to set (which is true) and therefore no smoke can penetrate the meat (not necessarily true). He therefore recommends starting your meat as cold as possible, so it has the longest time to absorb smoke before the surface layer of the meat exceeds 120F. Other experts, including an award winning smoked meat producer I know, argue the opposite - they recommend adding smoke primarily at the end of the process, long after the meat temperature will exceed 120F. Note that this answer is likely to be slightly different for meat, poultry and fish since their proteins denature at different tempertaures. Note also that the optimum temperature for absorbing smoke flavor during the smoking process is likely to be quite unrelated to the final cooking temperature - i.e. when the meat is done.

2. What is the optimum temperature to generate smoke? There are many ways to generate smoke. One method uses an electric hot plate on which you dump sawdust, chips or pellets of hardwood - what temperature is the best for this? Other methods involve burning whole wood. A web page, from the University of Illinois meat science department says that the best quality smoke is produced between 650F and 750F. Below 575 they say the smoke is too acidic. Meanwhile, the manfacturer of a high end computer controlled smoking system told me the opposite - that you need to be below 575 to get low acid. Note that this temperature issue is related to the next question.

3. Does wet or moist wood make more or better smoke? Many people believe that you get the best smoke from having wood (sawdust, chips, chunks or logs) which are wet or damp. Note that I don't mean whether wood is green (i.e. freshly cut from a tree) or not - I mean the moisture content. Those in favor of wet / damp /moist wood usually advocate adding water, soaking the chips in water etc. Others argue just the opposite! Note that having moisture in the wood will lower the temperature at which it burns, so the advocates of using moist wood may actually be asking for lower temperature (the previous questoin). Moisture in the smoking wood would also contribute to the humidity - the next question. Humid smoke tends to be more opaque and light colored - as the smoke leaves the fire and hits the air, it cools down and reaches the dew point, creating droplets of water - i.e. like condensing steam does, or a fog or cloud. So, moist wood that produces humid smoke might LOOK more "smoky" but that does not make much difference. My guess is that moisture in the wood is actually irrelevant except insofar as it determins wood tempertature or humidity, but it would be good to know this for sure.

4. What is the optimimum humidity (RH) in the smoke chamber for smoking? Many smokers use water to add humidity to the smoking chamber - that includes both popular "water smokers" as well as fancy commercial units that have humidity control. Note that pans of water in the smoke chamber also help to control the temperature by absorbing heat and boiling, especially in uncontrolled wood burning pits or converted grills. Some people will tell you that humidity aids in smoke penetration, others will say the opposite. This page says that 30% to 38% RH is optimum, but does not say why. Note that I am asking about smoke penetration - at some point in the process of smoking or barbequing one typically wants to develop a "bark" or crust. This may require different conditions than the smoke penetration phase.

5. How much oxygen should there be in smoke production? Some people advocate a "smothered" or smoldering fire which is under-oxygenated. Such a fire (regardless whether it is on a tiny chip on a hot plate, or a whole log) tends to burn with dark sooty smoke. Other people advocate a clean burning fire with sufficient oxygen, pointing out that black soot particles do you no good in penetrating the meat. As with moisture content, the amount of oxygen can surely affect the temperature. So when people try to starve a fire of oxygen they might be trying to leave more unburned hydrocarbons in the smoke, or it might just be a round about method of controlling the temperature.

Note that I have steered clear of topics like "is dry rub better than wet rub?", because those are much more a matter of personal taste. It is clear that you can season meat any of several different ways, and deciding what is "best" is pretty subjective.

I am hoping that somebody on eGullet will have some pointers to definitive works on these topics or be able to answer with some hard facts.

Or add your own questions that need answers.

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

Cooking time is something that is very misunderstood - the time depends totally on the thickness not the weight. This is true in regular cooking, but is particularly important in sous vide.

The key issue is the temperature of the water bath, or steam oven, in which you cook the sous vide bag, and the thickness of the meat in the bag. So, the difference between Joan Roca's timing estimate and another one is depends on how thick the meat was cut before being placed in the bag.

If you cook with the water bath at close to the final temperature, then it is slow to come to temperature, but as was pointed out above, you can leave it without fear of overcooking. THat is NOT true if you cook at much higher than the final temperature, then timing becomes important.

So, if you want a piece of meat to be 130F internal temp, I will generally put it in a 131F water bath. I will post some times later.

Roca and some others like to have a bigger temperature difference between the water bath and the final temperature.

Searing the beef is purely for appearance. I use a blowtorch often, but a hot pan or super hot broiler works too.

Beef is not very attractive after sous vide, particularly for long cooking times - the exterior is a greenish brown. If you envelope it in sauce that may be OK. If you have a beef fillet, most people expect a certain look.

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

There is an interesting article on sous vide in Slate...

[So what else can I blowtorch?]

MAPP is a gas similar to propane that burns a bit hotter. This can be important for doing silver soldering or braising. Most (but not necessarily all) propane torches can use MAPP as well.

I have used it for cooking purposes but i have not found any significant difference. A propane torch is already hot enough that there is no increased utility in MAPP.

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

How long does it take to cook an 6 oz. filet fo beef to medium-rare at 140 degrees?

Depends on a lot of things.

First off, 140F is closer to medium. There is no universal agreement.

Anyway, the key thing is not the weight, it is the thickness. If you put it in a water bath at 140F, it should probably take 30 minutes. The good news is that it won't over cook.

I would cook at 135F to get medium rare.

You'll have to brown the outside afterwards.

[What is the white substance oozes out of salmon?]

If you cook the salmon sous vide at 45C / 113F or below some juice will run out of the salmon. However, if you collect the jice and heat it, it will coagulate like a custard. It has very mild but interesting salmon flavor. I've served it....

[Cooking with Liquid Nitrogen]

No, I believe that what he does is siply pour the oil into a blown sugar bubble.

You could freeze things and then coat them this way I suppose. Albert Adria does lots of other things with liquid nitrogen.

[Cooking with Liquid Nitrogen]

My father used to regularly win bets from his colleagues at MIT by gargling liquid nitrogen.  I'm not sure what the trick was, but he never burned himself.  I'll have to ask him about it.

←

Yes, amoung irresponsible things that science types do with LN2, this is one of them.

I have not done it myself - I'm crazy, but not that crazy. I am sure it can be done, but it would seem that if it isn't done just right you'd have a real problem.

[Cooking with Liquid Nitrogen]

Chef Sean can reply on how he makes his cocktail spheres - I am curious too.

Here is a trick that may be similar. Take a mixture which normally does not freeze at typical freezer temperatures - for example something with lots of sugar in it (syrup), or lots of alcohol in it, or an oil that does not typically freeze.

You can use LN2 to freeze these things. Even pure vodka will freeze. Alcohol freezes at -117C, but LN2 is at -196C.

Once you've frozen the normally unfreezable liquid you can encase it in something else around it - say ice cream, mousse.... or a liquid which will stay frozen at normal freezer temperatures. Then you put the whole thing in the freezer and let it sit a while - usually overnight. Ironically the goal of putting it in the freezer is to WARM UP the core that was frozen with LN2, which then melts into a liquid. Obviously, the encasing should not leak.

Heston Blumenthal makes a mock egg this way that has a liquid yolk. The mock yolk has enough sugar and alcohol that will be liquid in a normal freezer. He freezes the mock yolk, then makes the mock egg white and molds it around the yolk and lets it stay in the freezer.

When the customer's spoon goes in, they find a liquid yolk.

This is a variation on things like Chinese soup dumplings where you freeze a liquid, encase it in something, then heat the something and serve with liquid inside.

You could do this with LN2 also. If you wanted vodka filled dumplings or syup filled dumplings you could freeze the vodka with LN2, encase in dumpling dough, then cook the dumplings. The only issue here is that your dumpling dough must be watertight.

[Cooking with Liquid Nitrogen]

There are several web sites that have full safety info, such as this

The following is provided for information only, use at your own risk.

The basic things are this:

- Get a pair of Tempshield cryo gloves - these are available from scientific supply places like Fisher Scientific and others. You want the waterproof model (there are also non-waterproof), and I like the elbow length ones.

- Get a cryo apron, also by Tempshield

- Get safety glasses, or a face shield. I use a full face shield that I happened to have already from using oven cleaner. Here is a similar one that from Amazon

The gloves and apron are ridulously expensive - like $150 each. I know people who use much cheaper gloves, or no gloves, but these are the correct ones to have.

LN2 is VERY cold. If it splashes on your skin it could really hurt you - or not. Surprisingly, if it falls onto a a convex surface (i.e. the back of your hand) it just falls off. You hand is so hot compared to the LN2 that it boils at the bottom and a cushion of nitrogen gas lets it fall off harmlessly. In graduate school (I was in physics) we would sometimes play irresponsibly with the stuff and have hallway fights with it ect. I've had it on my skin many times without a problem - even had it run down my back under my shirt.

If you pour a bit onto a flat surface - a plate, or pan - droplets will float and dance on teh surface until gone, just like drops of water will do in a very hot saute pan, and for the same reason.

BUT that's only if there is a way for it fall off. If it falls onto a concave surface where it will collect instead of fall off, such as the palm of your hand, well that is BAD.

Your biggest risk is having it splatter into your eyes - hence the shield or goggles. Any saftey goggles should do, but I like the face shield because it does not fog up.

The other risk is soaking into clothing - that is BAD. There are plenty of lab rats who work with the stuff that will tell you that the best way to handle LN2 is naked.

An example of a really bad thing to do is to spill some so it goes in your shoes. You'll lose a bunch of flesh that way.

So, I use cryo gloves and cryo apron. However, if I didn't have those I would use waterproof gloves and a waterproof apron, and maybe rubber boots.

The other main hazard is that when LN2 goes from liquid to gas, the volume increases. So, you NEVER seal it in a container. A popular stunt for physics grad students is to pour a bit into an empty 2 liter plastic soda bottle, then throw the bottle into a plastic trash can half filled with water, or into a swimming pool. The whole thing will explode. I don't mean a little explosion either.

So, NEVER seal it in a container. Never pour it down a drain - it will freeze the water in the sink trap, and can make it explode.

This all sounds bad, but I do not believe that LN2 is any more dangerous that fry oil. You wouldn't want to fill your shoe with hot fry oil either. In fact, it is probably more dangerous spilling hot oil on your hand than LN2.

I use the gloves and apron for pouring between the storage dewar (container you store it in) and the container that I use to dunk food in -(a open mouth dewar, or small plastic cooler). However, once I am using it I usually have at least one glove off. because they are just too cumbersome.

In practice you use the same sort of tools you'd use for frying in oil - i.e. tongs and mesh strainers to catch the food and bring it out. For some purposes, like making a powder by spraying a liquid into LN2 a fine mesh chinois is best.

[So what else can I blowtorch?]

Simple propane torches are available at Home Depot or other hardware stores - they connect to the top of a propane canister. You light them with a sparker, which usually comes with them.

Fancier torches are self lighting.

They are as safe as a gas stove. There is no way they can turn into a bomb through normal use. However, if you let propane leak out with the torch unlit ....well that is like having a gas leak.

[Sorbet: Tips, Techniques, Troubleshooting, and Recipes]

I've had quite a bit of sucess with a roasted tomato "ice cream". Basically it is oven roasted tomatoes and olive oil frozen and then ground in a pacojet. It has a great taste, perfect texture (due to the olive oil) and has zero sugar in it.

So this is one pure success and I did not have to use any specific texture ingredients, although that might not be a bad idea in other cases.

[Cooking with Liquid Nitrogen]

Have been cooking with LN2 a lot the last several weeks - the results are very interesting.

The most popular thing with people I have forced this on is flavored whipped cream, shot out of an ISI cream whipper into LN2, then almost immediately removed and served. Crisp and hard on the outside and cream on the inside. If you eat it quickly, what looks like smoke comes out your mouth and nostrils.

Olive oil freezes solid. If you spray it in, you get a crystalline olive oil powder.

Thick liquids can be dropped, drop-by-drop and it will freeze into little balls.

This stuff is fun to play with - although you need a lot of safety precautions so "play" is perhaps not quite the right word.

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

I've been going through the english version of Joan Roca's book Sous Vide - it is a great reference on the topic. Those fluent in Spanish already know this about the original verison, and I myself cooked with it for over a year but there are some interesting subtlites that come across when you can read in your native tongue.

This is highly recommended as the best book on Sous Vide.

It is also just about the only book on sous vide, but that isn't quite do it justice to say it that way.

[Dessicator....]

What you show there is a vacuum dessicator. It is available from scientific supply houses such as Fisher, Cole Palmer etc. The one shown is plastic, which I recommend. There also come in glass, but those are much more expensive.

Basically it is a vacuum chamber. The lower the atmospheric pressure, the faster water evaporates.

Dehydrators work by gently blowing hot air. A vacuum desicator does not need the heat so it is great for drying things that you want to do qucikly, or you don't want to heat.

In the case of the french fry example fromt the Fat Duck , the fries are already hot, but a vacuum will cause them to lose water even faster then they would at normal atmostpheric pressure.

You need a vacuum pump also - the one in the photo is a very fancy Buchi vacuum pump. A cheaper approach is a water aspirator, or an aspirator style vacuum pump. You need a vacuum pump that will tolerate water vapor.

[So what else can I blowtorch?]

I love my blowtorch, and use it for many things, particularly browning or crisping roasted items that need a touch up.

I use it quite a bit to brown things that are cooked via sous vide, which is a wonderful cooking method but it does not leave things brown or crisp.

Torches are far more intense heat than any broiler. This is a problem with some foods because parts will burn before the rest is brown. To some degree you can control that by moving it rapidly and holding it farther away. However, at some point you're better off with a broiler.

Propane is as safe as gas cooking is. MAPP gas and butane are similar. I would certainyl not cook with an acetlyene torch however.

[Water Baths and Immersion Circulators]

Fisher Scientific, Cole Palmer, VWR and others all have web sites where you can buy new lab water baths directly.

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

I ate at Can Roca a little while back . Joan Roca told me that his sous vide book will be coming out in English, hopefully later this year.

[Cooking with Liquid Nitrogen]

I just ate at ElBulli this week, and there were several terrific LN2 courses.