977 replies to this topic

[sasquatch]

Could anyone here give some tips on how not to run out of water (by evaporation) during very long cooking times, like 48 hours? I usually set an alarm for myself to wake up around 3 hours after I do my last "refill" or addition of water, just to make sure my pot doesn't run out of water which would shut-off my thermal immersion circulator.

[slkinsey]

Stretch a sheet of plastic wrap over the top of the pot. There will be a little open area over where the circulator goes in, but this is not a big deal. You can top-up the water by pouring into that same little open area.

Questions: How large is your water bath? And what temperatures are you using?

[sasquatch]

I'm doing 61C with around 30L of water

[NY_Amateur]

Are you experiencing a lot of evaporation at that level? I cover mine with aluminum foil, really anything should be fine. I did 55C for 36 hours for short ribs and with the aluminum foil did not have to refill it once.

[slkinsey]

Yea. You shouldn't experience significant evaporation at that temperature and that volume of water. If you cover the top of the pot with foil or plastic wrap, you shouldn't lose more than 1 liter in 12 hours . This rate of evaporation should not be a problem, and you should be able to sleep through the night with no worries.

[rmillman]

In a lab where we often use waterbatks at higher temps (and can be used when doing vegis sv), we use styrofoam packaging peanuts in the bath to keep down surface evaporation and better control temp if room temp changes a lot

[alwang]

Yeah, ping-pong balls are another similar solution that I used for a while. I've settled though on just covering my bath with a largish plastic cutting board. Seems to work well enough.

[KennethT]

I have a question for those who do the vacuum packing using a chamber vacuum... if sealing something with liquid in the bag (like a marinade or de-alcoholed wine, etc.) do you find that the liquid boils at the time when the vacuum is applied? If so, is it a problem during sealing? Thanks...

edit - also, what is the standard vacuum that is applied prior to sealing - without trying to compress watermelon or something...

Edited by KennethT, 22 October 2008 - 02:56 PM.

[NY_Amateur]

Ok so I don't have a chamber machine but I think I still have the answers

(edited out my very wrong answer, Douglas replied below with a much better answer)

The standard vacuum is basically as strong as your machine will go , you basically compress veggies at the same pressure you just seal whatever, you want to get as much air out for two reasons a) prevent/minimize gas expansion b) reduce oxidation for longer cook times. On modern machines this is close to a full vacuum, 20 millibars, about 29.33" of Mercury or .59" depending on the way you count em.

[DouglasBaldwin]

I have a question for those who do the vacuum packing using a chamber vacuum... if sealing something with liquid in the bag (like a marinade or de-alcoholed wine, etc.) do you find that the liquid boils at the time when the vacuum is applied?  If so, is it a problem during sealing?  Thanks...

edit - also, what is the standard vacuum that is applied prior to sealing - without trying to compress watermelon or something...

I actually do have a chamber vacuum sealer, and I can assure that the liquid almost always boils --- even olive oil.

A couple tablespoons of liquid in the bag isn't a problem --- even at a hard boil, the liquid does not expand enough to reach the seal bar. Vacuum packaging high water content foods (for freezing) is more problematic; when the liquid boils, its effective volume increases rapidly and will pour out the top if you are not careful.

Typically, I set my chamber vacuum to pull as strong of a vacuum as it can. Most chamber vacuum sealers use rotary vane vacuum pumps which can pull a medium vacuum* of 1 to 0.001 torr/mmHg (100 Pa to 100 mPa). If the food is moist, some of the liquid will change phase and displace the air in the bag with vapor. How much vapor depends on the temperature of the food; for water, the saturated vapor pressure is about 24 torr at 25C and 6.5 torr at 5C --- that means water at 25C boils around 24 torr and water at 5C boils around 6.5 torr. Assuming all the liquid doesn't boil away (a very safe assumption), then the strength of the vacuum pulled depends on the temperature of the food and how fast the gas in the chamber is removed --- that is, a steady-state is often reached where the amount of gas removed by the pump equals the amount of vapor generated by the liquid. So a particular chamber vacuum sealer can pull a much stronger vacuum on meat and marinade at 5C (with a vapor pressure of about 6.5 torr) than on hot soup at 80C (with vapor pressure of about 355 torr).

Vacuum sealing food with a high liquid content is tricky. If you want to vacuum seal a lot of liquid, it is often convenient to freeze it in metered portions and then vacuum seal the individual portions. If you insist on keeping things liquid, cool the liquid as much as is feasible to increase the strength of the vacuum you can pull. Then place the liquid filled bag on a sloped board inside the chamber vacuum sealer so the liquid is as far away from the seal bar as possible. Then either fill the bag with just enough liquid so it does not exceed the volume of the bag when it rapidly boils or watch the vacuum sealing very closely with a finger on the stop/seal button and try to catch it before it boils out of the bag and makes a mess.

* A medium vacuum is defined to be 25--0.001 torr.

Edit: Edited for clarity.

Edited by DouglasBaldwin, 23 October 2008 - 04:33 AM.

[hll]

Does anyone have a ideas on cooking a turkey breast sous-vide? I tried Thomas Keller's recipe from NY Magazine a few years ago for Thanksgiving, but wondered if there is any better info on cooking times/temps. Had a great and different texture when I did it last time.

Nothing in his new Under Pressure book on turkey.

His last recipe is here:
http://nymag.com/res...uitsousvide.htm

[zEli173]

After setting aside my foray into sous vide for a few months, I am back at it with my second attempt at duck "confit". I had to toss out my first attempt because my circulator shut off overnight and I had no way of knowing how long the food had been below safe temperature. But I rigged a new setup which has solved my evaporation problems of the past.

I didn't do a salt cure, so this is not strictly a confit (I usually find traditional confit overwhelmingly salty). The legs are being cooked with a good amount of salt, some rosemary, a few juniper berries, and a couple tablespoons of duck fat I had been saving. The duck has been at 180 degrees for almost 18 hours and I plan to go for a full 24. Although the standard thread recipe for duck confit is 8-12 hours I'm game to try longer.

I plan to sear the skin in a non-stick pan and serve with boiled potatoes and a frisee salad. But I'd love to hear other suggestions.

I do have one question which is only semi-sous vide related. Is it OK for me to keep leftover duck fat? And if so, what is the best way to store it and for how long? I'm thinking I will harden the fat in the fridge and then vacuum seal it.

[smashz]

Duck fat freezes just fine. You can put it into a tub and scoop out what you need - no need for vacuum sealing. I have two tubs - one normal, and one smoked. I often scoop out a tablespoon of it to enclose in a sous-vide item.

[DouglasBaldwin]

Does anyone have a ideas on cooking a turkey breast sous-vide?  I tried Thomas Keller's recipe from NY Magazine a few years ago for Thanksgiving, but wondered if there is any better info on cooking times/temps.  Had a great and different texture when I did it last time.

Nothing in his new Under Pressure book on turkey.

His last recipe is here:
http://nymag.com/res...uitsousvide.htm

I can tell you how I plan to prepare our turkey this Thanksgiving. [Although I am a huge fan of the molecular gastronomy movement, I stick to familiar flavors and seasonings for Thanksgiving.]

If frozen, thaw your turkey completely before proceeding.

If the bird was injected with brine before purchase, skip all the brining steps below.

Thanksgiving Eve:

Heat the water bath to 176F/80C.

Carefully remove the turkey breasts and gently remove the skin. Brine the breasts in a 3--5% salt solution (30--50 grams salt per liter water) for 3--4 hours. Salt and pepper the skin and place flat on a wire rack in the refrigerator until Thanksgiving day.

Remove the legs and wings and brine in a 7--10% salt solution (70--100 grams salt per liter water) for 3--4 hours.

Vacuum seal the neck, back and any remaining dark meat in a heat stable plastic pouch. Place the bag in the water bath.

After brining, rinse the turkey breasts, lightly season (with whichever spices you traditionally use), and individually vacuum seal each breast. Place the vacuum sealed breasts in the fridge overnight. [If you have two water baths, then cook the breasts for the time listed in Table 4.7 of my guide, rapidly chill in ice water for the listed in Table 1.1, and refrigerate until needed.]

Once the legs and wings have finished brining, rinse, season, and vacuum seal with a couple tablespoons of fat (duck, goose, lard). Then cook in the 176F/80C water bath for 8--12 hours.

Thanksgiving Day:

Remove the legs, wings and spine from the water bath (if cooked overnight). Rapidly chill the legs & wings in an ice water bath for the times listed in Table 1.1 in my guide.

Use the liquid and meat in the bag with the spine to flavor your gravy.

In a 141F/60.5C (or 146F/63.5C) water bath, pasteurize the breasts for the time listed in Table 4.7 of my guide. After pasteurizing, reduce the temperature of the water bath to 131F/55C and place the pouches with the legs and wings in the water bath to warm.

Just before serving, shred the dark meat from the thigh and wings. Either serve the shredded meat as is or place in a just smoking pan and brown one side. Using a Iwatani butane (or a propane hardware) blowtorch, crisp the skin on drumsticks.

Crisp the skin from the breast either between parchment paper sandwiched between sheet pans in a hot oven or using either a blowtorch or a smoking hot pan. Then, serve the breast garnished with the crisped skin.

[Baggy]

I’ve been experimenting with cooking steak sous vide and have come across an issue with the colour of the meat.

I’m using a chamber vacuum machine and pulling down to around 50 mbars before cooking at 52C for a rare/medium rare finish for anywhere between 20 and 90 minutes. As expected, the meat is moist and has the expected texture (although this varies widely depending on the quality of the meat and length of ageing).

Problem is the colour. Depending on which muscle groups are included, the colour is verging on grey (with a pink tint). It’s not the meat as I’ve done comparisons with the same lot of steak grilled vs sous vide, and grilled comes out pink. Also, some steaks come out with one of the muscle blocks a good red colour (as expected), but the other block a dreary grey.

First question is why?

Second, how do I stop this from happening?

[MikeHartnett]

sear it.

[e_monster]

Problem is the colour.  Depending on which muscle groups are included, the colour is verging on grey (with a pink tint).  It’s not the meat as I’ve done comparisons with the same lot of steak grilled vs sous vide, and grilled comes out pink.  Also, some steaks come out with one of the muscle blocks a good red colour (as expected), but the other block a dreary grey.

First question is why?

Second, how do I stop this from happening?

At 52C (125F), I am surprised that the meat is looking grey. Did it look grey to start out with?

For searing, (this is for flavor as well as coloring), you want a VERY VERY hot pan. I put my pan on high heat for about 10 minutes before I sear (which gets the pan to around 700F). I then sear for about 20 seconds per side. That is a short enough time that the heat does not penetrate to the interior of meat but long enough to get a nice crust (if the pan is hot enough).

You can also use a propane torch for searing if it has a strong enough flame (not one of those mini torches that are sold as creme brulee torches).

[nathanm]

Problem is the colour.  Depending on which muscle groups are included, the colour is verging on grey (with a pink tint).  It’s not the meat as I’ve done comparisons with the same lot of steak grilled vs sous vide, and grilled comes out pink.  Also, some steaks come out with one of the muscle blocks a good red colour (as expected), but the other block a dreary grey.

First question is why?

Second, how do I stop this from happening?

Lack of oxygen during cooking is the main reason. The outside of sous vide cooked meat typically looks grey, or even greenish. Not very appetizing, but that's how it is.

As others have mentioned, searing is the answer.

[DouglasBaldwin]

Nathan is of course absolutely correct that the grey (or even greenish) surface color of the meat is caused by a lack of oxygen. This lack of oxygen, is also the reason why beef cooked sous vide often looks pale when first cut but then becomes a bright red after being exposed to oxygen for a few minutes.

According to Lawrie's Meat Science, 6e, pp. 212--216:

The color of the meat depends on the quantity and type of myoglobin present. In general, the amount of myoglobin reflects the level of muscle activity. However, the concentration of myoglobin in a muscle can occasionally be several hundred-fold different over distances of 1 cm.

When (fresh) meat is cooked, the purplish-red myoglobin, bright red oxymyoglobin and brown metmyoglobin denature into brown globin haemichromogen. The extent of this denaturation depends strongly on temperature and weakly on time (the amount of denaturation increases slowly with time). Indeed, beef cooked to an internal temperature of below 140F/60C has a bright red interior; between 140F/60C--160F/70C a pink interior; and, to 160F/70C--175F/80C or higher a greyish brown. Below 150F/65C, myoglobin denaturation may be caused by enzymic action or co-precipitation rather than from temperature.

[Baggy]

Thanks for the responses.

As for searing – this is not the issue. I have tried searing the steak when cold (registered at 3-5C) and before putting in the water bath. Searing on a hot pan (measured at 280-310C with an IR thermometer) for 30 seconds a side increases the internal temperature by around 4-6C for a 2 cm thick steak; not as hot as e_monster suggests, but nowhere near enough to overcook.

Less searing time is insufficient to produce significant browning and, even at 30 seconds, whilst acceptable in appearance the grey surface colour shows through the griddle marks. Searing for 60 seconds a side gives a much better look.

Searing after the steak has been brought up to 52C is a problem, as the searing pushes a medium-rare into the realms of medium or medium-well done (2 cm steak).

As the internal colour of a steak like a rib eye (which has two different muscle blocks) can be pink in one and grey in the other, I favour the theory that it’s the deoxygenation/denaturation of myoglobin causing the grey colour problem.

Which leaves me with the question – is there a way of handling the meat so that denaturation of myoglobin is minimised?

Douglas – in your extract from Lawrie you mention co-precipitation as a possible cause. Do you have any more detail on this?

As I understand it, supermarkets often package meat in a modified, high oxygen or carbon monoxide atmosphere to preserve the pinkness and I came across this link on using rosemary to perform the same trick (anyone tried this?).

Any ideas how I can test the increased oxygenation alternative. Short of soaking the steaks in hydrogen peroxide in a pressure cooker (unheated), I’m at a loss as to how I can increase internal oxygen levels.

(edited to add carbon monoxide reference)

Edited by Baggy, 26 October 2008 - 12:51 AM.

[e_monster]

Have you tried searing after you sous-vide the steak? Searing after cooking is the solution -- not just for looks but for flavor and texture. I have done it both ways and find that searing after sous-vid-ing is best. If you sear afterwards, the color will be beautiful. Also, I wouldn't sear on a grill, I would do it on an actual pan -- you get a much nicer crust. At least that is my finding.

[Mikels]

I have a question for those who do the vacuum packing using a chamber vacuum... if sealing something with liquid in the bag (like a marinade or de-alcoholed wine, etc.) do you find that the liquid boils at the time when the vacuum is applied?  If so, is it a problem during sealing?  Thanks...

edit - also, what is the standard vacuum that is applied prior to sealing - without trying to compress watermelon or something...

Ok so I don't have a chamber machine but I think I still have the answers

(edited out my very wrong answer, Douglas replied below with a much better answer)

The standard vacuum is basically as strong as your machine will go , you basically compress veggies at the same pressure you just seal whatever, you want to get as much air out for two reasons a) prevent/minimize gas expansion b) reduce oxidation for longer cook times. On modern machines this is close to a full vacuum, 20 millibars, about 29.33" of Mercury or .59" depending on the way you count em.

Since the meat produces liquid, I reduce any liquid by 1/3 to 2/3, then freeze it. I have bags of wine, stock... in my freezer. If you can get Japanese ice cube trays, the cubes are 1 T.

Edited by Mikels, 26 October 2008 - 04:29 AM.

[smashz]

I just did a salmon fillet (with olive oil infused with bay, peppercorns, and vanilla) for the first time (at 45°C/113°F), and everyone loved the flavor. But several people found it to be unsatisfying because it was "cold." I've felt the same thing with a 52°C/126°F beef fillet.

Clearly, the SV method produces the temperature that it does, but has anyone else here encountered the sentiment, and how do you deal with it?

[e_monster]

While some people think salmon mi-cuit is to die for, there are a lot of people that don't seem to like it. Richard served salmon done at 113F on Top Chef and none of the judges liked the texture. I like it but my wife isn't thrilled by it.

If people like rare steak 126F won't seem cold them, but if they don't like steak on the rare side of med. rare than 126F may just not be to their liking. Did you sear the steak after cooking or serve it straight out of the bag? (If the steak wasn't seared after cooking that might contribute to their sense because the texture of non-seared sous-vie steak is missing something

One other thing -- and perhaps you already know this -- make sure to warm the plates before putting the food on it. 126F steak and 113F salmon will VERY quickly lose their heat on a room temperature plate. (This is true of most sous-vide).

Anyway, that is my opinion.

[sygyzy]

I was checking out Under Pressure last night and I was reminded that my Foodsaver is not the ideal vacuum sealer, especially when it comes to pressure. It certainly cannot compress foods (ie melons) and is not good at all with liquids. I bought and have used it a few times for SV but I would be lying if I said it was a vacuum was strong and the food was packed.

With that said, I can't afford an Ultravac machine. Is there something more in the middle? Preferably < $400 and readily available?

[NY_Amateur]

So another option for the foodsaver and liquids that I have found to work decently well, is to use a very very long bag and basically dangle the liquid over the edge of a counter. It will still inch up due to the capillary effect but you should be able to get a decent vacuum before it reaches the sealing edge, I have used this technique to seal liquids in the bag before.

This may cause issues at high temperatures as the gas left expands but you can weight the bag down with a wire rack or something on top and be ok.

[slkinsey]

Freezing the liquid is probably the best method, although I have also had pretty good results using a long bag as NY_Amateur suggests.

One technique I use is to use NY_Amateur's "long bag" method and then manually seal the bag again much closer to the food items.


I have not had any difficulties achieving the vacuums necessary for 99% of sous vide applications using a bag sealer. I also noted looking at the pictures in "Under Pressure" that plenty of the bags had small amounts of internal air clearly visible.

[e_monster]

Since I upgraded from my 5 year-old FoodSaver to a new one with the Pulse option, I haven't had a problem with liquids or too much air in the bag. The removable drip tray means that it doesn't matter if some liquid gets sucked out of the bag. My old FoodSaver sometimes left more air in the bag than I was happy with (which sometimes resulted in enough air to float the bag.

Freezing the liquid is probably the best method, although I have also had pretty good results using a long bag as NY_Amateur suggests.

One technique I use is to use NY_Amateur's "long bag" method and then manually seal the bag again much closer to the food items.


I have not had any difficulties achieving the vacuums necessary for 99% of sous vide applications using a bag sealer.  I also noted looking at the pictures in "Under Pressure" that plenty of the bags had small amounts of internal air clearly visible.

[smashz]

If people like rare steak 126F won't seem cold them, but if they don't like steak on the rare side of med. rare than 126F may just not be to their liking. Did you sear the steak after cooking or serve it straight out of the bag? (If the steak wasn't seared after cooking that might contribute to their sense because the texture of non-seared sous-vie steak is missing something

One other thing -- and perhaps you already know this -- make sure to warm the plates before putting the food on it. 126F steak and 113F salmon will VERY quickly lose their heat on a room temperature plate. (This is true of most sous-vide).

Anyway, that is my opinion.

I just did a salmon fillet (with olive oil infused with bay, peppercorns, and vanilla) for the first time (at 45°C/113°F), and everyone loved the flavor. But several people found it to be unsatisfying because it was "cold." I've felt the same thing with a 52°C/126°F beef fillet.

Clearly, the SV method produces the temperature that it does, but has anyone else here encountered the sentiment, and how do you deal with it?

Yes, I do sear the meat in a hot (600F+) cast iron skillet; I've done this since my very first trials (except when I did the 2-hr. BBQ and then put it into SV). But that thin layer is not like a normally cooked fillet, which has a relatively thick warmer surface, even if the interior is still rare. (Of course, I did not sear the salmon.)

I have warmed the plates, although not meticulously. I'll pay more attention to that in the future.

[alwang]

Anyone have any experience using the Auber/SousVideMagic controller with a portable induction hob? Does it work well? Is it safe for long cooks?

Thanks,
-Al