1176 replies to this topic

[Guy MovingOn]

Sure forced circulation does make a difference, see http://forums.egulle...ost__p__1729644 . My stockpot is 9L nominally, I use 7-8L water and an indoor fountain pump, and I never noticed a problem with meat cuts up to 700g or up to 3 bags, hanging vertical on a skewer (see http://forums.egulle...ost__p__1699134 ). If your bag is not in a vertical position, it might impede convection. As your bath is a bit shallow (post #3304) you might at least bring your bag to an oblique position by placing some weight in the bottom of the bag, see post #3384.

Thank you for your suggestion. Yes, from the top of the waterline to the base of the bath is approximately 15cm. I do occasionally use a skewer to keep things in a vertical position, or use some of the excess plastic from the evacuated vacuum bag anchored underneath the waterbath lid to keep the food in an appropriate position.

My waterbath also came with a metal grill which has about 2cm clearance underneath, so that incase an item was to sink to the bottom of the tank, it wouldn't sit against any heaters, and would also allow currents of water to pass beneath it.



However, I would be interested in an effective method of forced convection in water of a temperature up to 80C. I know people suggest air stones... but how effective are they at regulating and circulating 7 litres of water to be at complete uniform temperature??

Edited by Guy MovingOn, 24 March 2010 - 10:33 PM.

[e_monster]

Air stones are quite effective for things like rice cookers and tabletop roasters (probably anything whose heat source is not in a concentrated area) as long as there is space beneath and above whatever is being cooked.

[PedroG]

Ok, so I did some tests comparing the waterbath's thermometer to the Medisana Fever thermometer. The results are as follows. The water was stirred for approximately 10 seconds before the reading was taken so that there was an even temperature in the waterbath, since I am trying to ascertain the waterbath thermometer's accuracy and not the waterbath's ability to keep a uniform temperature. Of course there could be a variance of water temperature inside the bath.

The only real discrepencies happen at above 41C, with a offset of about 0.2C, which is not present at any temperatures lower than 41C.

Waterbath Fever thermometer
32.2C 32.2C
32.5C 32.5C
33.0C 33.0C
33.5C 33.5C
34.6C 34.6C
35.6C 35.6C
36.0C 36.0C
37.1C 37.1C
38.2C 38.2C
39.1C 39.1C
40.0C 40.0C
41.1C 41.1C
41.5C 41.8C
41.8C 42.0C
42.5C 42.7C
42.9C Too hot



I also don't think this is a relevant issue, but just to note, during this experiment these temperatures were taken with the waterbath's lid off, and in normal operation, the lid would be placed on. I don't think this is particularly relevant to the thermometer's accuracy... but could help explain the temperature variation inside the bath.

Hi
extrapolating your measurement pairs, your bath would have effective 55.36°C with the display indicating 55.0°C. BUT: quis custodiet ipsos custodes? It might as well be that a cheap fever thermometer is calibrated at 37-38°C but may be off at higher temperatures, but how can we know?
OK, continue cooking longtime at 55.0°C, you should be on the safe side anyway.
Pedro

[Paul Kierstead]

The only real discrepencies happen at above 41C, with a offset of about 0.2C, which is not present at any temperatures lower than 41C.
...

Your numbers are looking pretty good. It is a very good thing to check, especially if you are doing long cooks at low temps, or are having results which don't "seem right".

[Guy MovingOn]

Yes, I was actually quite surprised at the accuracy... but then wondered why there would suddenly be an offset of 0.2C above 41C.

I suppose the next thing to check would be the variance inside the bath with unstirred water. Either that, or I just find a method of forced circulation.

[Guy MovingOn]

However, I would be interested in an effective method of forced convection in water of a temperature up to 80C. I know people suggest air stones... but how effective are they at regulating and circulating 7 litres of water to be at complete uniform temperature??

Air stones are quite effective for things like rice cookers and tabletop roasters (probably anything whose heat source is not in a concentrated area) as long as there is space beneath and above whatever is being cooked.

My waterbath has heating elements on 3 sides, which apparently improve convection currents. Do you think in my situation an airstone would benefit? As PedroG noted, my waterbath is a bit shallow (15cm from the base to the waterline), but there is always some space beneath the bags for water to circulate.

Cheers :)

[e_monster]

The question is how much variance is there in the bath. Having more sides heating does not necessarily translate to better convection. For example, a stockpot on a heating plate or a simple rice current have great convection that results in very minimal variance in the bath. By contrast, my tabletop roaster has heating on the sides, too and there is enough variance to require an airstone. With the airstone there is next to no variance in the bath. I would say that if you have temperature differences more than 1/2 degree Celsius that it is worth using a bubbler (the air stone itself doesn't matter. It doesn't require a lot water movement to stabilize the temps in something like this).

It looks like your bath is well-calibrated. So, maybe you are looking for your meat to be red rather than pink?

Btw, you mentioned cooking the brisket at lower temps -- keep in mind that safety issues aside, the collagen breakdown gets much slower as the temperature goes down. So, even if were safe to cook it below 55C, it would take a long time to get tender. And if the meat at 55C isn't red enough you would have to go down more than a couple of degrees for there to be a substantial difference. (Note that I am not recommending doing that but thought that the issue was worth mentioning)

[Paul Kierstead]

Also, of course, searing technique could affect doneness.

[JanK]

Ive researched pumps that will handle sous vide type temperatures. I kept coming up with the March 809 pump. Apparently, it's the standard pump that home brewers use, since the beer making stuff is at higher temps. The capacity is probably way more than any of us would need, but I haven't found anything smaller that is rated for reasonably bigh temps. It's not cheap ($110-150 US), but it's not outrageous. They can be ordered from pump supply places, or from home brewing supply shops. if you want a high temp water pump, that's the one I would get.

Here's the nice part: If you've got a healthy size heating element, you could use a relatively small volume "heating bath" and then use the pump to recirculate the water to and from a large container (something like a big plastic bin, a small stock tank, or a galvanized tub, etc.). That way, you could cook really big stuff (like maybe a whole brisket?). That's essentially what Hester Blumenthal did when he sous vide'd a whole pig. He did it in a hot tub, which is more or less the same concept. The heater is seperated from the bath, and the water is just pumped from one area to the other..

My home built SV outfit, which is crude but effective, has dual heating elements. It's got a standard 1200W water heater element ($12) plus a 300W travel style immersion heater ($6). My container is a 24L rigid polystyrene restaurant supply container with a lid. I use the big element to get the water up to temp (since it takes forever using the small one), then switch to the smaller element. The whole thing fits inside of a polystyrene foam container, which provides remarkably good insulation. Because I am cheap (and poor), I'm just using a "bang-bang" Ranco controller ($55). It does the job though. I'll try to post some pics of my outfit when I get a chance if anyone is interested in seeing it.

I don't use a water pump in my setup. A really cheap aquarium pump with no airstone seems to work well. I just use the suction cups that are designed for the tubing to keep it in place at the bottom of the tank.

[Guy MovingOn]

The question is how much variance is there in the bath. Having more sides heating does not necessarily translate to better convection. For example, a stockpot on a heating plate or a simple rice current have great convection that results in very minimal variance in the bath. By contrast, my tabletop roaster has heating on the sides, too and there is enough variance to require an airstone. With the airstone there is next to no variance in the bath. I would say that if you have temperature differences more than 1/2 degree Celsius that it is worth using a bubbler (the air stone itself doesn't matter. It doesn't require a lot water movement to stabilize the temps in something like this).

It looks like your bath is well-calibrated. So, maybe you are looking for your meat to be red rather than pink?

Btw, you mentioned cooking the brisket at lower temps -- keep in mind that safety issues aside, the collagen breakdown gets much slower as the temperature goes down. So, even if were safe to cook it below 55C, it would take a long time to get tender. And if the meat at 55C isn't red enough you would have to go down more than a couple of degrees for there to be a substantial difference. (Note that I am not recommending doing that but thought that the issue was worth mentioning)

Those are some points which I haven't considered. There is a pet shop a few minutes away which seems to sell some aquarium accessories, so I will see if they sell a bubbler. I haven't really seen them in use, but just from their name I didn't expect them to be so effective. I will definitely check it out.

Yes it could be an issue that I like my beef to be very rare, but even from the photos they meat wasn't particularly pink. Also it was rather dry on the mouth feel. It might be the particular breed - I don't know how Aberdeen Angus brisket compares to others, whether it is already more tender and the 48 hours was excessive? But the duration doesn't explain the colour so much.

I will attempt to check the variance in my bath maybe tomorrow if I have time.

[Guy MovingOn]

Also, of course, searing technique could affect doneness.

Yes, but in my example, I did neither a pre, nor post, sear...

[e_monster]

Yes it could be an issue that I like my beef to be very rare, but even from the photos they meat wasn't particularly pink. Also it was rather dry on the mouth feel. It might be the particular breed - I don't know how Aberdeen Angus brisket compares to others, whether it is already more tender and the 48 hours was excessive? But the duration doesn't explain the colour so much.

I will attempt to check the variance in my bath maybe tomorrow if I have time.

I have found that sourcing of briskets makes a big difference. I cooked brisket from a few different sources before I found one that I really liked. Keep in mind that the "flat" section of a brisket is often not very juicy due to the marbling pattern. So, it can have a pretty dry mouthfeel even if it is a good quality piece of meat. If at 48 hours it was fork tender, try 36 and see how it is. Some briskets need a solid 48 hours at these temps to be tender, but the Wagyu brisket that I mentioned recently, was fork tender at 24 hours.

[Paul Kierstead]

Yes, but in my example, I did neither a pre, nor post, sear...

Ah, well then, that definitely wouldn't explain the whole pink thing then :) But it might contribute to the dryness. I find a really good sear renders off quite a bit of fat near the surface and definitely helps make things moist. And tasty :)

[Guy MovingOn]

I have found that sourcing of briskets makes a big difference. I cooked brisket from a few different sources before I found one that I really liked. Keep in mind that the "flat" section of a brisket is often not very juicy due to the marbling pattern. So, it can have a pretty dry mouthfeel even if it is a good quality piece of meat. If at 48 hours it was fork tender, try 36 and see how it is. Some briskets need a solid 48 hours at these temps to be tender, but the Wagyu brisket that I mentioned recently, was fork tender at 24 hours.

Yes you are quite right, I noticed too that the thinner end of the brisket was noticeably drier than the thicker end, which had more fat. Ironically, my gf and I were fighting over the fattiest parts of the brisket!

I have located what could be a reasonable butcher not too far from where I am, so once I get the chance I will take a look at what cuts they have. I really would like to try short ribs en sous vide, but I don't think they are a popular cut at all here in the UK.

I'm currently confit-ing pork belly. It will probably go for around 14 hours or so at 80C. It was brined with salt, pepper, clove, cinnamon, all spice, bay leaf, thyme, and dry white wine for 36 hours.
Since I don't have any rendered pork fat, and only half a jar of duck fat, I put a combination of duck fat, goose fat, and olive oil in the bag. Hopefully it will benefit from the combination of fats, and not suffer :)

After cooling I plan to store it for as long as I can resist (probably only a few days!) before deep frying it in the fat that was in the bag! Probably serve it with a salad, to try to make the dish somewhat less heart-stopping!

Edited by Guy MovingOn, 26 March 2010 - 11:40 AM.

[Phaz]

Has anyone tried to SV Wagyu strip steaks? Allen brothers has a special going on now and I'm tempted to try it.

From what I know about Wagyu the goal is to have a low temperature (Wagyu fat renders at a lower temp, or so I've heard) and then sear the outside with a ridiculous amount of heat. I've tried them before on the grill with a pizza stone and found it was very difficult, only about 15% of the pieces I did had that taste that you go for.

I'm thinking it might work doing a whole steak and searing with the torch to get that perfect cut. Maybe doing them at 117 or 120. I've seen posts of larger cuts of Wagyu here, but is curious if anyone has ever done steaks or bite sized pieces?

Edited by Phaz, 26 March 2010 - 01:04 PM.

[jk1002]

I thought about it but stopped.

I had a somewhat thin slice, maybe half inch american wagyu strip steak. I felt if I SV it and then sear it for a nice crust I would loose too much fat.

If you have a different shape, maybe more cube like or a thicker cut I would give it a whirl.

[PedroG]

Yes, but in my example, I did neither a pre, nor post, sear...

Ah, well then, that definitely wouldn't explain the whole pink thing then :) But it might contribute to the dryness. I find a really good sear renders off quite a bit of fat near the surface and definitely helps make things moist. And tasty :)

Quite so!

GuyMovingOn, maybe your expectations on SV are too high.

What you can do with SV is:

• Cook tender meat foolproof as tender and juicy as can be to any desired doneness
• Cook tough meat fork-tender and pink with the texture of a steak (typically 55°C)
• Cook tough meat fork-tender and well-done with a falling-apart texture like braised meat (e.g. 77°C for fastest melting of collagen, about the highest temperature before meat becomes shoe-leather)

What you can not do with SV is:

• Cook tough meat tender to a doneness corresponding to less than 54.4°C

If you do not sear your meat, you miss the flavor and salivation-provoking effect of the browning products from the Maillard-reaction.

[PeterF]

I've been cooking sous vide for about 6 months now. Bought a good quality Auber PID and pricey thermometer that I'm using mostly with a hotplate and large lobster pot. Holds it's temperature within at at least .2 degrees c without an aquarium pump.

One thing I've found based is that other than eggs, there is nothing I cook that requires an exact temperature within 2-4 degrees f. Eggs, if I recall correctly an online video demo with Joel Rubichon, are perfectly cooked at 146.5f but will come out differently .5 f higher or lower. Other than that I haven't found precise accuracy matters much (other than keeping it above 131f when cooking more than 4 hours for hx reasons.) I enjoy Salmon Miu Cuit at 104 and a steak medium rare (upper 120's), but if either were +/- a couple degrees I don't think I would notice.

Other than eggs, are there any other foods people can think of that would require cooking at precise temperatures within a degree or two?

[e_monster]

Has anyone tried to SV Wagyu strip steaks? Allen brothers has a special going on now and I'm tempted to try it.

From what I know about Wagyu the goal is to have a low temperature (Wagyu fat renders at a lower temp, or so I've heard) and then sear the outside with a ridiculous amount of heat. I've tried them before on the grill with a pizza stone and found it was very difficult, only about 15% of the pieces I did had that taste that you go for.

I'm thinking it might work doing a whole steak and searing with the torch to get that perfect cut. Maybe doing them at 117 or 120. I've seen posts of larger cuts of Wagyu here, but is curious if anyone has ever done steaks or bite sized pieces?

I would prepare a Wagyu strip steak the same way that I would prepare any tender steak. Wagyu fat renders at lower temps than 'standard' beef but NOT so low that it will render when cooked at 133F or below.

Cook at whatever temp you prefer. Personally, I find 127F to 130F to be ideal for tender steaks. Lower than that and even tender steak feels a bit chewy. The thicker the steak the better.

If you want to serve small portions, I would cut them into cubes after searing. Personally, I find strip steak not to be nearly as flavorful as rib eye. With Wagyu beef, you get a special tenderness but it is no more tasty than traditional beef -- at least in my opinion.

Btw, at Alinea they cook their wagyu steaks sous-vide. Then chill them then warm them to a lesser temperature right before searing.

[Paul Kierstead]

Other than eggs, are there any other foods people can think of that would require cooking at precise temperatures within a degree or two?

In my experience, 2 degrees F would make a difference in fish, but admittedly no where near one big enough to cause disappointment.

[Guy MovingOn]

I was confit-ing belly pork last night at 80C. Following the recipe I had cut up the belly pork into roughly 2.5cmx3cm chunks, brined for 36 hours, then dried and bagged with some fat.

I was intending to let them cook at 80C for anywhere between 12-16 hours. It was 18 hours when I realised that I hadn't taken them out of the bath yet. There is a lot of fluid from the bag. I presume it is the extra liquid taken on by the meat in the brine, plus some of its own juices.

I have read about a 3 stage cooling process to try to maximise juiciness of protein which has been cooked en sous vide. I believe that small chunks of meat (admittedly they were all in the same bag, but no more than 4cm thick at all) cooked at 80C for 18 hours should be relatively safe/sterile, so I have tried cooling them more slowly than I would normally with anything cooked at lower temperatures for shorter times.

Is this the best way to try to improve the juiciness of the meat, or is it a lost cause? Also, is it potentially dangerous? I would have thought that 80C for 18 hours is a very high temperature for a very long period of time, and that almost all bacteria would have been destroyed.

BTW, once the contents have cooled, I plan to deep fry them before serving.

Thanks for your opinions!

Edited by Guy MovingOn, 27 March 2010 - 09:12 AM.

[Guy MovingOn]

Just to note, the contents are being refrigerated, I just wanted to cool them down slower. I guess it would have taken a couple of hours for them to cool to room temperature. I know that traditional confit can be stored at room temperature - some people say indefinitely. Also I think my temp/time combo will put me on the safe side, I just wanted to double check!

[slkinsey]

If you are going to keep the meat in the sealed bag, you want to chill it as rapidly as possible for safety reasons. Dropping the bag in an ice-water bath is the usual way.

[e_monster]

Is this the best way to try to improve the juiciness of the meat, or is it a lost cause? Also, is it potentially dangerous? I would have thought that 80C for 18 hours is a very high temperature for a very long period of time, and that almost all bacteria would have been destroyed.

BTW, once the contents haofve cooled, I plan to deep fry them before serving.

Thanks for your opinions!

The safety issue is largely the spores as they are much harder to deactivate than the bacteria. I would stick to Doug Baldwin's recommendations.

[DouglasBaldwin]

...
Is this the best way to try to improve the juiciness of the meat, or is it a lost cause? Also, is it potentially dangerous? I would have thought that 80C for 18 hours is a very high temperature for a very long period of time, and that almost all bacteria would have been destroyed.
...

The safety issue is largely the spores as they are much harder to deactivate than the bacteria. I would stick to Doug Baldwin's recommendations.

e_monster is correct. The spores of Clostridium perfringens will easily survive your 80C (175F) for 18 hours. Rapid cooling (in ice water) is the best way to prevent sporulation of C. perfringens.

[Guy MovingOn]

Thank you for the clarification on the cooling.

The process to which I was referring was Bruno Goussalt's multi stage cooling, which I read about in the NYTimes article Under Pressure (http://www.nytimes.c.../14CRYOVAC.html), when after having cooked the food en sous vide, it is then "cooled, successively, at room temperature, in cold water, then in ice water, before being reheated and served." I had read a discussion about this multi-stage cooling process earlier in this thread, and thought it was concluded that this method improves the juiciness of the protein.

Douglas could you please help my confusion! Btw, I am still going to pasteurise a chicken breast at 55C and report back to you! Sorry I haven't gotten round to doing it yet! I was a big fan of 57.5C chicken, but consider that to be almost as low a temperature as I would want!

[DouglasBaldwin]

Guy MovingOn,

The difference is in the context: Mr Goussalt is concerned with industrial sous vide cooking and we are interested in home and restaurant sous vide cooking. If you're trying to cool thousands of pounds (kilograms) of food, successively cooler baths makes a lot of sense. At our scale, it's much easier for us to drop the cooked food into an ice bath until the core's cold enough.

That multi-stage cooling improves juiciness hasn't been shown to my satisfaction. First, I'd only consider it when doing braises (i.e., at 70C/160F and higher). In the small scale experiment I did for myself a couple years ago, there was a small difference but it was within my expected error. I've never gotten around to doing a larger scale experiment to see if there is a statistically significant difference. Personally, I usually let my braised pork sit on the counter for about 15 minutes before placing them in my ice bath --- but this is mainly to cool the pouches enough so they're not painful to handle.

Edit: Typo

Edited by DouglasBaldwin, 28 March 2010 - 05:03 PM.

[Andrew Chalk]

Do you crumble the crispy skin or just lay a sheet from the salmon on each fillet?

[Guy MovingOn]

Guy MovingOn,

The difference is in the context: Mr Goussalt is concerned with industrial sous vide cooking and we are interested in home and restaurant sous vide cooking. If you're trying to cool thousands of pounds (kilograms) of food, successively cooler baths makes a lot of sense. At our scale, it's much easier for us to drop the cooked food into an ice bath until the core's cold enough.

That multi-stage cooling improves juiciness hasn't been shown to my satisfaction. First, I'd only consider it when doing braises (i.e., at 70C/160F and higher). In the small scale experiment I did for myself a couple years ago, there was a small difference but it was within my expected error. I've never gotten around to doing a larger scale experiment to see if there is a statistically significant difference. Personally, I usually let my braised pork sit on the counter for about 15 minutes before placing them in my ice bath --- but this is mainly to cool the pouches enough so they're not painful to handle.

Edit: Typo

I believe that it is not only in industrial applications where he has recommended this process. He obviously consults to several restaurants, and I believe that it was earlier in this thread that lecture notes or photgraphs from these seminars were posted.
However, having reread this thread, I have come across posts from several people, including NathanM, who have stated that the three stage process should not be used.



I suppose then, that traditional confit is safe to store at room temperature indefinitely, but sous vide confit must be refrigerated?

[nickrey]

Do you crumble the crispy skin or just lay a sheet from the salmon on each fillet?

I cut square shapes, place a small cut in the salmon and the place it like a little sail in each fillet.

Otherwise you could just lay it on the fillet.

The skin is eaten like a little piece of pork crackling.

I haven't tried it crumbled.