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

[johnsmith45678]

Sous vide sounds like an irresistible topic for a Good Eats show. Assuming it's practical for the home cook...

Edited December 2, 2005 by johnsmith45678 (log)

[jsolomon]

Nope, sorry. Unitasker.

It would make for an interesting show, and likely out of the range of most viewers, but depending on your level of insanity, you can pick up a decent water bath, new, from VWR for ~$600.

Cheaper would be a crock pot and a PID, but a DIY project.

The problem with some of those is capacity. A 20L water bath is great, but you could only sous vide for about 8 people or less.

[johnsmith45678]

Is sous vide something that could be done in a big pot of water on the stove?

[jsolomon]

There's no reason why it couldn't, but it would need careful watching (and a trustworthy cooktop)

[Shalmanese]

Hrmm... interesting. Would you still get Maillard at 90C? A quick back of the envelope calculation indicates that to maintain a vacuum would require evacuating about 1 - 10L of air per second at standard pressure. It seems theoretically doable to me.

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Yes, you would, but very very slowly. Hours instead of minutes.

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But you wouldn't fry something for hours so no significant malliard should occur with vacuum frying. I wonder what the benifits of it are then.

nathanm could you tell me more about your vacuum flask for reduction? I've always wanted to try vacuum reduction. How fast does it reduce? How do you think the taste differs from normal reduction? Are there any things you can do with it that you can't do using normal reduction? I've always wanted to try reducing various fruit juices using vacuum reduction. I imagine you could come up with some pretty intense sauces this way.

john Good Eats already did a show on LT poaching. The only difference with sous vide would be the bags.

[jsolomon]

But you wouldn't fry something for hours so no significant malliard should occur with vacuum frying. I wonder what the benifits of it are then.

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I believe pounce answered that in this post.

By putting the cooking under a vacuum you can lower the fry temperature and reduce the amount of acrylamide you generate duing the cooking by up to 90+%.

[nathanm]

nathanm could you tell me more about your vacuum flask for reduction? I've always wanted to try vacuum reduction. How fast does it reduce? How do you think the taste differs from normal reduction? Are there any things you can do with it that you can't do using normal reduction? I've always wanted to try reducing various fruit juices using vacuum reduction. I imagine you could come up with some pretty intense sauces this way.

It's really very simple - you need a vacuum pump that can take moist air, and a filter flask - which has a vacuum port, a stopper and some tubing.

The simplest vacuum pump is an aspirator - fits on a faucet and you run tap water through it to create a vacuum. There are more complicated vacuum pumps, but you don't need a high vacuum for this.

Depending on how hard a vacuum you pump, sauces or stocks will boil at room temperature. It is exactly like normal boiling EXCEPT the temperature is lower. Just like normal boiling it can be a rolling boil, or a simmer. You can heat the flask to speed the boiling up but that tends to remove the reason you're doing this in the first place...

Taste difference comes in only through temperature. If you want to reduce something without heating it, this is the way. It works great.

[Shalmanese]

Have you tried reducing delicate substances that would be destroyed by heating? One of the things I always wanted to do was to get fresh watermelon juice and reduce it until the sugar level is high enough and then make a sorbet from it. I've never successfully made a watermelon sorbet since the flavour is so diluted but I image a vacuum reducer would be perfect for it.

Have you tried something like this or other things which would be impossible using high temp reduction?

[nathanm]

Yes, this is exactly the point of doing it. I have not specifically tried watermelon juice but this is exactly the point - you can concentrate delicate juices without heating them.

[Mark Sommelier]

The first part of this article talks about watermelon Thomas Keller style. The rest of the article might explain some of the concepts of sous vide cooking more clearly. I work in a restaurant that Mr. Goussault has been consulting at for more than a year. This is as much science as it is culinary artistry.

Under Pressure

Moderator's note: broken link -- CA

[pounce]

Now I really want to try this vacuum reduction technique. When Shalmanese mentioned watermellon reduction I was sold. I think the key to trying this at home is a proper vacuum pump that can handle the moisture. Nathan points out using a hydro aspirator which would work perfectly in this case if it can pull enough vacuum. Basically this is a venturi vacuum pump that uses water to create the draw. One issue I have with using a hydro aspirator is that it can use a lot of water. Maybe 1.5 gallons a minute or more. The other option is to use compressed air instead of water. Obviously, this is not as convenient for most people since they may not have an air compressor handy. Also, not many people want to run a noisy compressor (and venturi pump) in their kitchen. I'm ok with dooing experimental cooking in the garage so I'm looking at something like this compressed air powered pump. For the container I'm going to try using a Food Saver storage container. I already have some from when I bought my vacuum sealer. I'm assuming they can handle a fair amount of vacuum without imploding and they are foodsafe. I may also be able to sink it into my water bath if needed to raise a temp slightly. Heavy mason jars like the freezer versions with a vacuum fitting screwed into a lid may also work. Lab vacuum glass just seems so expensive and even though I think having a lab on my kitchen island is about the coolest thing I can think of my girlfiend is already afraid of my water bath ...heh.

[DocDougherty]

After a series of experiments I settled on sous vide turkey thighs (about 16 oz each), 24hrs @ 165°F (actually 23hrs @ 165°F and 1hr @ 153°F, see below). They were cooked bone-in, trimmed, skin on, seasoned with only salt, pepper and a (very) little garlic. When they come out you can just pull the bone out and lift the skin off. They are so tender it is a good idea to use an electric knife to cut them up into chunks. They were a big hit.

I also did turkey tenderloins seasoned with salt, white pepper, a little butter, and a pinch of poultry seasoning. They were about an inch thick in the bag so I cooked them at 153°F for 60 min.

Four thighs and four tenderloins augmented a 15 lb bird that I did in the combi (with less satisfactory results) as the main course for 15.

I think I am going to try doing a sous vide turkey in the combi.

Does anybody have a starting point? Time, temp, humidity? Brown it first? Or at the end? Or let it cool off a little and then brown it just before serving? Or brown it first, go wet, low, and slow, then dry it out and crisp it up at the end?

[nathanm]

After a series of experiments I settled on sous vide turkey thighs (about 16 oz each), 24hrs @ 165°F (actually 23hrs @ 165°F and 1hr @ 153°F, see below). They were cooked bone-in, trimmed, skin on, seasoned with only salt, pepper and a (very) little garlic. When they come out you can just pull the bone out and lift the skin off. They are so tender it is a good idea to use an electric knife to cut them up into chunks. They were a big hit.

I also did turkey tenderloins seasoned with salt, white pepper, a little butter, and a pinch of poultry seasoning. They were about an inch thick in the bag so I cooked them at 153°F for 60 min.

These temperatures are quite high, but if you like the result, then great.

The thighs are cooked very similar to the manner in which you'd cook a duck confit. You might want to try making it even closer to duck confit - see the duck confit thread. Basically, you salt the thighs/legs and let them sit (brining also works). Then cook with several tablespoons of buttor or oil in the bag. I'd try 170F to 180F for 8 to 10 hours.

You can also try lower temp on the breast tenderloins - I do them at 140F - but again it is up to you.

I think I am going to try doing a sous vide turkey in the combi. 

Does anybody have a starting point?  Time, temp, humidity? Brown it first?  Or at the end? Or let it cool off a little and then brown it just before serving? Or brown it first, go wet, low, and slow, then dry it out and crisp it up at the end?

Cooking sous vide in a combi-oven is the same as cooking in a water bath. Use the steam setting and use the same temperture as you would do for a water bath. Steam transfers heat to food much better than dry air, which is why you must use the steam setting.

There is no agreement on whether you should brown sous vide food before you bag it, or do it after you un-bag it the end. Both work. The difference is that if you brown first you will not get a crispy / crusty exterior because it will get soggy in the bag. You can do a three stage approach where you brown, bag, then re-brown - that would work too - but I'm not sure what the advantage would be, and it is an extra step.

You can also cook turkey at low temperature in a combi oven without using a sous vide bag - either a whole bird or parts. It is difficult to do a whole bird sous vide because of size - a turkey won't fit in most vacuum packers. In addition, the interior cavity of the bird means there will not be great heat applied there. Whole sous vide squab and quail work well - even some small chickens. But if you want to do a whole turkey it is better to do it as follows.

There are an infinite number of combinations for how to program time and temperature. Here is a simple approach is to put the combi-oven on steam mode at the same temperature you'd use for sous vide. Use the time from the tables for the thickest part of the bird, and or use the thermometer probe. Here is an example, which I have done in my combi-oven.

1. Prep bird normally - truss, salt & pepper etc. Run your hand UNDER the skin, loosening the skin from the body - do this for breast legs and back. If you want you can season under the skin with flavored butter or oil. Poke some holes in the skin in any areas where fluid may be trapped under the skin when the bird cooks. The reason to loosen and perforate the skin is to make it brown better in the last step below. Also, the very tips of the wings may get too dark in the browning step so it may be better to cut them off.

2. Preheat the combi-oven to 145F in steam mode.

3. Place the bird wire rack in the combi-oven , NOT in a roasting pan. If you want to catch drippings, put a pan under the bird, one rung lower than the bird. You want air to circulate all around the bird. There will not be a lot of drippings in this method. Steam in combi-oven at 145F - until probe registers 140F in thickest part of the bird.

4. Continue steaming at 145F for another 30 minutes AFTER the core temp is reached. This is for food safety concerns - simply coming to temperature is NOT enough - you need to sit at tempertature for a while. Also, this gives you some saftey factor in case the probe was not in the thickest part.

5. Remove bird from oven - dry with paper towels, and rub skin with oil or butter. At this point the bird is done but won't be browned. Let the bird sit while the oven is preheating - it's not necessary to cover it. If you used a dripping pan to catch drippings remove it now - you dont' want it in for the next step.

5. Turn combi-oven up to the highest setting - generally 500F (or potentially even higher) and 0% humidity. Let it reach that temperature BEFORE you put the bird in.

6. Return the bird to the oven (again, on a wire rack) to brown the skin. Watch it carefully so it does not over brown.

7. Remove from oven. Use a blowtorch to add final touches for browning parts that did not get quite brown enough.

This produces a very nice roasted bird with an interior texture similar to sous vide.

Nathan

[DocDougherty]

Nathan,

Thanks again. I have previously found that 15 min @ 475°F is long enough and hot enough to get uniform browning (if, as you point out, you have loosened the skin and oiled it when it was dry). I will incorporate your guidance into the next set of experiments.

Doc

[johnsmith45678]

Sous vide hot water heaters. Hmmmm.....

[jsolomon]

You literally could... depressurize one and chop the top off of the tank...

[nathanm]

The first part of this article talks about watermelon Thomas Keller style. The rest of the article might explain some of the concepts of sous vide cooking more clearly. I work in a restaurant that Mr. Goussault has been consulting at for more than a year. This is as much science as it is culinary artistry.

Under Pressure

It is a good article for summarizing some of the history of sous vide. There are a lot of inaccurate things about the article - it is discussed in the big eGullet sous vide thread.

[jsolomon]

Have you tried reducing delicate substances that would be destroyed by heating? One of the things I always wanted to do was to get fresh watermelon juice and reduce it until the sugar level is high enough and then make a sorbet from it.

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Is the flavor destroyed by heating, or is it more volatile than water? If volatility is the case, you should be able to distill it off before the water, save that fraction, then drive off the water and reintroduce the flavor.

Edit to add: if anyone is looking for a chemist to experiment in their kitchen, I'm looking for a good job!

Edited December 6, 2005 by jsolomon (log)

[Shalmanese]

Thats another thing I have been experimenting with is, trying to capture what I call the top notes (flavour compounds that have a boiling point below 100C and are, thus driven off by boiling). My first attempt was a jury rigged system which involved placing a large metal bowl over a pot of simmering stock and then dumping a load of ice on top of the bowl. In theory, the steam should hit the bowl, condense and then drip down the sides to a jury rigged al-foil collection pan. However, there wasn't enough cooling power and I could get the water from the steam but not the volatile top notes.

My next attempt has been rather more successful, I've mentioned the pressure cooker I have several times already in other threads but one unique difference about it is that it relies on a computer controlled thermostat, not a flame. This means that not one drop of steam escapes once the lid is attached. I can bring something up to pressure and press the pressure release valve, while holding a cup over the vent and capture all the top notes into the cup.

I've been meaning to write up a lot about what I've been doing but I haven't had time yet. Long story short, top notes are often more unpleasant than I would have imagined although there are some surprises.

However, I don't think that's the problem with watermelon, the flavour of watermelon doesn't seem especially volatile (Smell watermelon, it's not very fragrant) but it gets tranformed by cooking so another method is needed of reducing it.

The other idea I've had is inspired from eating ice-blocks as a kid. If you take a block of frozen juice, you can suck it so that all the flavour is sucked out and only the ice remains. If I could build a machine to do that at home, I could make an effective reduction without resorting to heat or a vacuum. It would have the added benifit of preserving all the top notes. However, I haven't had time to sit down and nut out any engineering diagrams yet.

[nathanm]

Thats another thing I have been experimenting with is, trying to capture what I call the top notes (flavour compounds that have a boiling point below 100C and are, thus driven off by boiling).

This is a very important point. Any food that smells really good while cooking is losing the very compounds that smell so good! That's why you can smell them - they are being evaporated off into the air.

A system to capture those volitile compounds could be very interesting.

[jsolomon]

In organic chemistry distillations, we call those "cold fingers".

Here are some examples.

[pounce]

I think that if you put a cooling condenser between your vacuum jar and your hydro aspirator you could capture your extraction before it got sucked out. A simple condensor could be built with vacuum hose a second vacuum jar and a container to hold ice. You would just want to cool the extraction down lower than your source by enough to keep the extraction from boiling as well. I wonder if this would work.

If you want to capture the steam off a boiling pot on the stove this is pretty easy. You could just build a basic condensor with tubing running fitted to a pot lid then through some some loops in a cold bath. This is a basic stovetop still. Made one of these when I was a kid. I had this crazy idea I wanted to be a moonshiner.

[Shalmanese]

Yeah, the problem with simple distillation is that you capture all the water back as well. What you really want is fractional distillation. The glassware for that costs on the order of $1000 which is not too bad but the volume is very low. Maybe if you get into more fancy stuff like using a still you could get better output but it's not something you could put on a countertop.

[nathanm]

Acutally there are several ways to do this.

You can make fractional distillation at any scale, and it is not that costly. It is complex, but that is another matter. The typical lab glassware set up is for small volume but it is not that bad to scale up. Plus the total amount of volitiles is actually pretty small.

But you don't really need to do fractional distillation if you do a two stage process. Or another way to say this is that fractional distillation is a one step process where you want to have two condensates - the water and the volitile fraction. If you do this as a two step process it is much simpler.

So, suppose you want to do a reduction of a liquid (stock, watermelon juice, whatever).

First you do one reduction where you vacuum reduce at low temp. The best way is to use a rotary evaporator which has a condensor column (a cold finger is one design, but there are many kinds of condensor designs). However you could also rig one up another way. The first stage reduces the water, and anything more volitile than water.

Then you take the condensate (which is water, plus volitles) and in a second step you vacuum distill just the condensate in the rotary evaporator. This time you adjust the heat and vacuum so that you are above the boiling point of water and you only get the volitile fraction. Which you can then add back into the reduction.

It is unclear to me how important this is - i.e. how much of the "high notes" volitile fraction can you really taste in the final dish. Most highly aromatic compounds in food seem to be in sufficient concentration that this is not an issue. So while it is true that food that smells great as it cooks is losing something, it's not like the food is tasteless afterwards. Quantitatively it true that you are losing something, but I am not sure if qualitatively you will be able to tell using taste as the metric.

I wonder whether capturing the volitiles in this manner is really going to result in a big perceptual difference? I bet there are cases where it would, but I also bet than it most cases it won't....

[jsolomon]

To follow up on what Nathanm put upthread, if you are doing fractional distillation without a fractional distillation column, one thing you will want is a decent thermometer to pay attention to the temperature, so you can control your distillation.