Sous Vide: Recipes, Techniques & Equipment (Part 7)

[PedroG]

As Pedro says, the key is insulation. Most water baths have very low wattage - 1000 to 1800 - which is about like a toaster. A typical home oven is 3500 to 7500 watts. So a water bath is quite weak.

Depending on the insulation of the pot/water container there will be some watts lost. This could be large or small, depends on the level of insulation. The more insulation, the more water you can put in your bath.

THe more water there is, the lower the temperature drop when you put food in which is good. Unless you put proportionately more food in! If the ratio of water to cold food you plunk in the bath is too extreme (i.e. too little water for the food) then you get a big temperature drop and it will take a while (perhaps too long) for the temperature to recover.

I find that 7 liters is about the smallest bath that makes sense, and frankly 20 liters is much better. But no matter what the size, don't jam it too full.

Heat loss and steady state energy consumption of sous vide cookers

Steady state heat consumption of a water bath can be approximated by

Steady state power [Watt] = cooling slope [°C/min] * water volume [liter ≈ kg] * 60 [min/h] * 1.163 [Wh/kg/°C]

1.163 Wh/kg/°C is the specific heat of water, i.e. the energy necessary to heat 1kg water by 1°C.

Another approximation is steady state power = Hs/(Hs+Cs) * Wn, where Hs = heating slope and Cs = cooling slope and Wn = nominal wattage.

Although these approximations do not account for the thermal capacity of the body of the cooker or water-bath, the calculated values reflect effective measured values quite well.

I collected the basic data of the same cooker with various insulations and of different cookers. Data of the Tiger have been contributed by blackp. Basic data of cookers were collected by pseudo-open-loop-tuning with the SVM 1500D PID-controller: when the proportional band is set to P=0, then instead of Integral and Derivative one can set hysteresis (I set HY=5°C) which is the range between switching power off and on (bang-bang-control). This allows automatic logging of heating slope and cooling slope.

To verify the calculated steady state powers, I tried to measure the power consumption directly with an energy cost monitor, but this did not work with the short energy pulses output by the SVM. So I plugged the FMM-heater to a Variac instead of the SVM, allowing to set the voltage to achieve stable temperature, and I measured voltage and power with two multimeters connected parallel and serial.

Here are a few examples from my experience:

Cooling slopes were determined at 55°C water temperature and 22°C ambient temperature.

Measurements of steady state power confirmed the calculated values.

As Nathan says, insulation is the key.

Part of the heat loss is caused by water evaporation; with the uncovered FMM, evaporation was about 110ml/h which accounts for a loss of 70W (evaporation enthalpy of water is 0.627 kWh/kg). So covering the bath saves 70W by avoiding evaporation and another 30W by an insulating layer of air.

Insulating and covering the polycarbonate container of the FMM may reduce heat loss by a factor of 4 and approximate the insulation of a rice cooker. Using a well insulated beverage cooler instead of the polycarbonate container has the same effect.

Just for fun: cooking a suckling pig sous vide in a bath tub is quite energy consuming!

Who will contribute the data from a SVS and other SV-rigs?

Here is an example of pseudo-open-loop-tuning:

Below is the FMM in the same configuration as above, run with continuous power 69V / 2.85A to yield 197W, which maintained 55°C very well.

I thank blackp for contributing his data for the Tiger rice cooker and Douglas Baldwin for his suggestion to verify the calculated power values by direct power measurements.

[Chris Amirault]

Re: Rick Bayless's SV carnitas:

[H]ere's a brief rundown from the show.

• Generously season a pork shoulder
  
• Bag with a healthy amount of fresh rendered lard
  
• Cook sous vide for 50 hours at 143f
  
• Remove from bag, shred into pan
  
• Cover with plastic wrap, layer another tray on top
  
• Add weights, transfer to refrigerator
  
• Once cooled/pressed, slice into cubes and brown
  
• Serve with oaxacan black beans, roasted tomato sauce, guac, lime, pickled red onions, microarugula
  

After two days at 62C, I've just shredded and packed this into two loaf pans, which are bound with elastic bands and in the fridge. One note: there was a cup of liquid in the bag, which I strained and poured over the shredded meat in the pan before compressing it. More later with results.

[shacke]

Buy a propane torch, but use MAPP gas.

MAPP is similar to propane but it burns hotter, and has less of an issue with flavor transfer.

I prefer "self-lighting" or "trigger start" propane torches. They are about $50 - available at Amazon, or Home Depot.

Even better, in my view, are torches that give you a hose between the tank and the torch - they are much less tiring to hold. here is an example.

The non-self lighting torches are cheaper - less than $20.

Very late in getting back to this thread. Thanks, Nathan for these recommendations.

[shacke]

Without knowing what cuts of steak you are cooking and the time/temperature, it is very hard to offer any advice as to how to improve your results. If the interior seems 'flat', I can think of two possibilities: 1) poor quality meat or 2) inappropriate time/temperature for the cut being cooked.

Thanks and yes I was being vague although I have no recent specifics other than some recent drab but tender chicken breasts.

As a point of experimentation, can you give me a suggestion for a newly purchased skirt steak? A chewy childhood favorite,I would think this could be really delicious SV. Any suggestion for time/temp and marinade would be appreciated.

[dougal]

...

Heat loss and steady state energy consumption of sous vide cookers

...

... suggestion to verify the calculated power values by direct power measurements.

My N2006P PID has an undocumented feature.

Thinking that it looked VERY like the Auber SYL-2362A2, I downloaded its manual and compared.

The Auber has a 'manual' mode whereby you can 'dial in' a chosen output duty cycle. (Press 'SET' for 5 seconds.)

I tried this on my N2006P, and it did something slightly different. (I think the two units have different firmware, the passwords are different, even if the hardware, and much else does seem awfully similar.) The Auber is generally more feature-rich and thus versatile, potentially justifying its higher price.

What mine gave me on pressing and holding 'Set' was nevertheless very interesting. And not in its own manual.

Instead of showing measured and target temps, it then displays measured temp and the continually varying (auto-controlled) output duty cycle as %. It shows the PID output!

One facet of this is that it shows how steady (or not) the bath is. You can see how the controller is working -- and that was a massive help to me when trying to improve on the autotuned settings.

Anyway, at an indicated (Pt100) steady 56C (ambient about 22C) the PID tells me that it is on for 8% of the time (±0.2%).

This was controlling a nominally 1800 watt heating element.

So I was running about 144 watts. Add a very few for the controller itself and some inevitable losses in the SSR, and I'd confidently say that I was using about 150 watts for cooking.

This was a "27 litre" (think 27 US quarts) water bath (filled to the 'max' line), uninsulated except for a brilliantly well-fitting lid. Incidentally its a Lidl "Jam Maker - Fruit Preserver" -- basically a 'canning' waterbath or tea urn - an enamelled steel vertical cylinder with a 'concealed element' under the waterbath floor, and with a convenient drain tap and even a nice grid to keep bags and things off the heated floor.

Massively lower cost than a big rice cooker ...

The Lidl 'Jam Maker' may not be much use for making jam, but its a bargain sv heated waterbath!

Incidentally, my home digital Energy Monitor is comprehensively fooled by the 2 second cycle of the PID (the monitor gives a reading every 6 seconds and is clearly not expecting a rapidly varying demand!) So don't expect to get a 'direct measurement' from such devices ...

I'm going to have a go sometime with some insulation. I was thinking of repurposing a foam (camping) 'sleeping mat'.

However, since I'm relying on pure convection to stir the bath, I shall only insulate the lower 2/3 of the water depth.

That way, I should expect to still get cooling at the sides of the surface, giving a downdraught.

Certainly, if the insulation is effective, I'd expect to have to retune the PID. One reason for my procrastination!

[nickrey]

I went to a really good butcher and bought a whole lot of meat, including some brisket which was not expensive compared to the other cuts I bought. The brisket was visibly a fine piece of meat from which I trimmed all the excess fat.

Bottom line was when I cooked it (72 hours at 57C), the product was far superior to other briskets I have done sous vide.

I know I've been banging on about it a bit but the quality of the meat matters. Go for the cheaper cuts by all means, they are the most tasty, but make sure it comes from a quality animal. Otherwise we get the failures that have been reported in this forum.

[e_monster]

Without knowing what cuts of steak you are cooking and the time/temperature, it is very hard to offer any advice as to how to improve your results. If the interior seems 'flat', I can think of two possibilities: 1) poor quality meat or 2) inappropriate time/temperature for the cut being cooked.

Thanks and yes I was being vague although I have no recent specifics other than some recent drab but tender chicken breasts.

As a point of experimentation, can you give me a suggestion for a newly purchased skirt steak? A chewy childhood favorite,I would think this could be really delicious SV. Any suggestion for time/temp and marinade would be appreciated.

Enter 'skirt' in the Search Topic field near the bottom of the page. You will find specific skirt steak recommendations.

[paulraphael]

Quick question: do you find any need for resting sous vided steaks after resting? I did a trial today with a hanger steak (3 hours at 56C, glucose wash, hot skillet). It came out gloriously, although it lost quite a bit of juice when I sliced it. Not sure if a quick rest would help or be pointless.

[Chris Amirault]

Shouldn't need to rest -- that is, allow the heat to distribute more evenly through the meat -- after you're done with SV, but if you blast the meat in a pan during browning and bring the exterior temp way above the interior temp....

[RDaneel]

I think that short ribs are the cheap cut that undergoes the most luscious transformation. They are juicy and beefy and are great if you have decent quality short ribs.

Well, e_monster, I'm putting this to the test! ;-)

I have about six pounds of pretty nice looking boneless beef short ribs in the bath at 132F, going to give them 48 hours, then chill and reheat for an hour to bring up to temp for torching and serving. That will free up the circulator to do a Keller dessert recipe from his PolyScience book.

As I understand it, I'll be long past the point of pasteurization at this point, so cook-chill-hold is totally ok, and it will really simplify my prep when guests are there.

I'm hoping to be posting my own "I just tried SV short ribs and was blown away" story next week!

[dougal]

...

As I understand it, I'll be long past the point of pasteurization at this point, so cook-chill-hold is totally ok, and it will really simplify my prep when guests are there.

...

Yes.

However, there is a "but".

Its wrong thinking to take 'pasteurisation' as being absolute.

Its an acceptable (massive) reduction of the nasties.

Not their elimination.

Hence i think its important to chill fast (ice and a minimum of water to contact the bags).

Then you could hold (at properly-cold-fridge-temp) for at least a couple of weeks ...

Reheating to your serving temperature ought also to be as quick as you can. So, from fridge straight into a preheated bath. And then you should have plenty latitude in service-holding time, once you are back up to temperature.

The initial wide 'business' interest in SV seems to have been exactly this simplification of service/assembly with reheating chilled pre-prepared portions -- hence the pejorative "boil-in-the-bag" associations.

Yes, I know the very beginning was with Foie Gras, but here I'm referring to the wider (trade rather than profession, if you will) take-up of the technique.

Edited September 4, 2010 by dougal (log)

[Chris Amirault]

Wanted to report back on the final steps of Bayless's SV carnitas (recipe here). Here are the loaf pans:



The pork removed from the pan:



At this point, I got concerned that the pork wasn't sufficiently firm to survive being sautéed. Forging on, I sliced it into ~3/4" slabs:



Into a non-stick pan with plenty of very hot lard:



Carefully, carefully tried to turn them, but... uhh...:



OK, so it's not going to be featured in Modernist Cuisine:



However, it was absolutely fantastic. The meat was infused with the spices and the texture was perfect, with tender and crispy bits in good ratio. It was insanely rich. It's a good thing I sautéed only a few slices or else I'd have eaten the entire thing.



Of course, the big question here is: why did the pork fall apart in the pan? One culprit could be the liquid, but I'll sacrifice form for flavor without concern. I'm quite sure it's not a sautéing issue: they started to break down almost immediately, so even a very fast high heat sear wouldn't have worked.

I'm thinking it was lack of collagen. Here are Derek's images of Bayless's pork:

On 23 August 2010 - 11:42 PM, derekslager said:

Pressed:

That looks like a lot firmer bind than I had, and even if I had left out the liquid, there was no way that pork was going to gel like that. Next time, I'll try it with skin-on pork and see what happens.

Having said that, this is a great addition to my growing SV repertoire and a terrific way to prepare carnitas.

[FoodMan]

On 04 September 2010 - 07:17 AM, Chris Amirault said:

Wanted to report back on the final steps of Bayless's SV carnitas (recipe here). Here are the loaf pans:

Carefully, carefully tried to turn them, but... uhh...:



OK, so it's not going to be featured in Modernist Cuisine:



However, it was absolutely fantastic. The meat was infused with the spices and the texture was perfect, with tender and crispy bits in good ratio. It was insanely rich. It's a good thing I sautéed only a few slices or else I'd have eaten the entire thing.

Of course, the big question here is: why did the pork fall apart in the pan? One culprit could be the liquid, but I'll sacrifice form for flavor without concern. I'm quite sure it's not a sautéing issue: they started to break down almost immediately, so even a very fast high heat sear wouldn't have worked.

I'm thinking it was lack of collagen. Here are Derek's images of Bayless's pork:

On 23 August 2010 - 11:42 PM, derekslager said:

Pressed:

That looks like a lot firmer bind than I had, and even if I had left out the liquid, there was no way that pork was going to gel like that. Next time, I'll try it with skin-on pork and see what happens.

Having said that, this is a great addition to my growing SV repertoire and a terrific way to prepare carnitas.

I think it is definitly lacking some more gelatin. Your idea of keeping the skin on next time is a good one. Also it looks like the shreds are too big. Try smaller shreds of pork. I hope to try this soon as well. The only similar meat I cooked and sliced dlike that was a shoulder of deer. It worked very well, so I guess deer shoulder had more than enough gelating on it's own.

[nickrey]

Are.those seared strawberries in your dish? What a clever accompaniment to game.

[FoodMan]

Are.those seared strawberries in your dish? What a clever accompaniment to game.

I wish I could take all the credit for the charred strawberries with game idea. I actually got it from the Alinea Mosaic forum here. In the Alinea dish they serve them as a component in a squab dish. If you want to know more about my venison dish, I blogged about it here.

[ScottyBoy]

Try this again...anybody?

Hey guys,

When you cooked the duck skin on between silpats do you use any weight on top?

Whats the ratio for this glucose solution you speak of?

Thanks in advance!

[ScottyBoy]

Sorry I don't know why I can't edit my post above but somehow I missed you guys answering the glucose question, thanks!

[ScottyBoy]

Rib eye cooked at 140 for 75 minutes then finished on the grill. Pork loin at 140 for 45 mintes. Both were awesome, pork was spot on.

Edited September 7, 2010 by ScottyBoy (log)

[PedroG]

Self-explaining:

Times are from D. Baldwin's 'A Practical Guide to Sous Vide Cooking'

[Moderator's note: I've attached the pdf that Pedro created. Thanks, Pedro! CA]

Thickness ruler.pdf

[Chris Amirault]

Printing note for US residents: for proper printing of Pedro's "caliper chart," be sure to set the paper source as A4 and turn off page scaling. If you lack A4 paper, legal will do the trick.

[PedroG]

Sous vide rigs may fail, so there should be an alarm when temperature deviates from the set-point.

Lately it happened to me that the FreshMealsMagic triggered the GFCI (ground fault circuit intterrupter) and bath temperature dropped from 49°C to about 48°C during 2h20' cooking. This did not cause me any problem, but if it happens during a 48h-cooking without being noticed, you have to discard your food. It may also happen that a sensor fails or shifts and bath temperature rises or drops.

As my SV-rig resides downstairs in the air-raid-shelter, I looked for a way to baby-sit my SV-rig without going downstairs every hour, and when ordering Nathan's book at Amazon, I also ordered a two-channel remote smoker thermometer Maverick ET-73 which arrived yesterday. It has a channel for the food temperature with a high-alarm and a channel for the oven temperature with high- and low-alarm; the latter can be used to sound an alarm whenever the bath temperature goes outside your set limits.

A known issue with the ET-73 is poor range, especially through walls. I had to place the receiver on the kitchen floor as near to the transmitter as possible to get a signal. So I hacked the receiver and did the Maverick ET-73 Range Modification From LilSmoker with a small modification shown in the pictures below, soldering the antenna wire to the rear side instead of the front side of the small PCB with the horseshoe shaped circuit board antenna, so the antenna wire does not have to be bent to exit the case. Now the range is sufficient to place the receiver anywhere in the kitchen and have a good signal. It's far from the 100 feet that Maverick claims, but an air-raid-shelter is a bit of a Faraday cage, so I am satisfied with the result. It is possible to make a similar modification on the transmitter, see http://www.instructables.com/id/Increasing-the-Range-of-a-Wireless-BBQ-Thermometer/, but in my case this was not necessary.

0.7mm SS antenna wire soldered to the rear side of the small printed circuit board

Small PCB replaced after soldering the antenna wire to its rear side

Length of the antenna wire measured from the soldering point has to be exactly 6.5" / 16.5cm which is the quarter wavelength of 433MHz

Small notch in case to accommodate antenna wire

The end result.

As I was still not quite satisfied with the range, I did the antenna hack also on the transmitter:

Preparing: remove insulation on antenna arc

Bend wire (16.5cm length from soldering point) so it can be threaded around the antenna arc to improve mechanical stability

Soldering wire to the antenna arc

Receiver and transmitter hacked.

Range was a bit better, but after extending the antenna on the transmitter from 16.5cm (quarter-wave) to 66cm (full-wave, on recommendation of Robert Jueneman), it was even better, now connection seems to be stable across a ceiling of reinforced concrete.

Although the ET-73 has some drawbacks, it is a (the only?) way to baby-sit a SV-rig and sounding an alarm, should the temperature deviate too much.

[Camano Chef]

I have had excellent results precooking chicken for frying SV

Cook thighs and drumsticks for 1 hour plus at 60 degrees C.

Dip in buttermilk and dredge in seasoned flour.

Deep fat fry at 177 degrees C. until golden brown.

Chicken is very moist and crispy. I have had excellent reviews each time I have served it.

Phil

[Phaz]

I have had excellent results precooking chicken for frying SV

Cook thighs and drumsticks for 1 hour plus at 60 degrees C.

Dip in buttermilk and dredge in seasoned flour.

Deep fat fry at 177 degrees C. until golden brown.

Chicken is very moist and crispy. I have had excellent reviews each time I have served it.

Phil

Has anyone tried this with Keller's Ad Hoc recipe? I like the idea of SVing the chicken first but it seems like with a recipe as precise as his that could lead to over cooking. Or do you bring the chicken to room temp or something beforehand?

[lesliec]

Your gauge is brilliant, Peter - thanks very much.

A laminated one would be nice - maybe I'll try sticking one in a vacuum bag. What cooking time would you suggest ... ?

[Chris Amirault]

Prepared a rack of St. Louis ribs as follows:

Rubbed with this rub.

Cold smoked (80-90F?) for two hours with a combination of apple and hickory in the Bradley.

Bagged and cooked SV at 67C for 26 hours.

Removed from bag and doused with =Mark's outstanding SC barbecue sauce, a house staple.

Grilled over blistering coals for about 2 min per side.

Best. Ribs. Ever.