Water Baths and Immersion Circulators

[alwang]

For those who've had more practical experience using an immersion circulator, is it preferable to have a water vessel that's tall and narrow (i.e, stockpot-shaped), or a vessel that's wide and shallow (i.e., hotel-pan-shaped), or does it not matter?

I'm particularly thinking when you have multiple bags in the vessel, is it important that they are side by side, to maximize exposed surface area, or is it okay to stack them on top of each other?

Thanks,

-Al

[tomtom11]

Has there been any movement towards consumer-grade baths? I'm uncomfortable using recycled lab equipment when I don't know what it was doing before, and I'm unwilling to spend the amounts required for a new circulator.

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Yesterday I did an experiment with my big heavy-weight Creuset pan to make a stable temp water bath. I managed to keep 63C up for quite a while (then I went to bed) by keeping the convection oven at a temperature of 100C. My assumption is that the heavy pan keeps enough energy to ensure a stable temp of the water.

What I did was:

1) heat up the oven very well (up tot 160C) to ensure there is enough energy in the casing of the oven. Keep it there for 10 minutes or so, then turn back to 100C

2) heat up de creuset with the water on the gas stove to the desired water temp (63C) using a digital meter

3) put the creuset in the oven and set the alarm of the meter to 64C (which never alarmed)

I figure that when you want to add for instance salmon, you put it in the creuset after step 2, but put the creuset only in the oven when the water is back to 63C. Also, you might want to have the oven a bit higher then 100C because of the temp of the product. And then use the alarm to ensure you don't go higher then 63C (and then lower the temp or even open the door shortly. Unfortunately I don't have a meter which alarms when going below a temp.

It's more tedious, but also nice starting point. It also requires getting to know your oven very well. I also intense heat below instead of fan. With other bath temps you also need to adjust things. Advantage is also that you don't need to worry about stirring the water (I suppose).

What do you think of this?

[Joseph Fenush]

I have recently purchased 2, B Braun thermomix 1480's... apparently both heavily used. They have analog controls which I have been unable to understand so far. Both heat and circulate but I cannot seem to control the temperature... They both seem to heat to about 65 celsius no matter what I seem to set the gages at. Anyone else have any experience with this type of model?

Its funny these things were manufactured in West Germany, they are probably older than some of my dishwashers, possibly some of my cooks! Any feedback would be greatly appreciated

[stephenc]

Two things.

a) I'd love to see someone do the methanol idea. Just give me the name of your opthamologist after you go blind or the name of your insurance adjuster after you blow up the house.

b) If using a used laboratory water bath for cooking, I'd highly recommend disinfecting it first with Virkon S, and then following it up with an 80% ethanol or isopropynol solution. Then repeat. Then repeat again.

All the laboratory baths I've used were N-A-S-T-Y.

Edited February 8, 2007 by stephenc (log)

[andiesenji]

I've been following this topic for a couple of years now and I keep thinking that some of these solutions are very similar to re-inventing the wheel.

As far back as the late 1930s, several appliance manufacturers actually perfected the electric roaster, complete with a rack and with fitted interior cooking containers so that an entire meal could be cooked at one time, each in its own separate container. The temperature range was wide - they came with an optional canning rack for both sterilizing containers and for processing canned fruits and vegetables (except for the few types that required steam canning.)

The nice thing about these was the fact that they could be turned on and did not have to be constantly. They were designed specifically to operate for several hours safely.

I have several - mostly because I collect vintage appliances, but also because I use them.

These were the precursors to the Crock-pot or slow cookers, only they were much, much larger. I have one that is a 28 quart, most were 24 or 25 quart. More recently 18 quart "roasters" came on the market.

Perhaps the term "roaster" is a stumbling block for some people who, not having grown in a time when these were common, have no idea how versatile they are.

When filled with water, as it is heated, (and food containers are on the rack) the water circulates on its own because of the way the heating coils are arranged. I have noted this many times, and the water rises all around the outside edge and rolls over into the center.

The lowest setting on all of my vintage roasters, Westinghouse, Nesco, Hamilton Beach and GE, is 150 degrees F.

There is actually a slighty lower setting on the Westinghouse, which if you had the original cookbook, from 1951, was for proofing yeast dough.

The vintage appliances often show up on ebay, some are fairly rare and go for serious money.

However, a few years ago some appliance manufacturers must have noticed that these things were selling because they began producing them again.

I walked into Wal-Mart one day and saw a prominent display in the center aisle.

NEW! Cook an entire meal while you are away for the day.

And the name was the old, familiar Nesco brand. Two were crockpot size, but there were also 12 quart and 18 quart.

They have a removable liner which is easy to clean.

[Joe Blowe]

I've been contemplating a Nesco cooker and temp. controller hookup lately, but haven't had the time to move forward.

Anyone have anything to say, positive or negative, about the Traceable No. 4130 (as linked above)? I would use this setup just as a way to "get my feet wet", used mainly for thick cuts of meat, not delicate fish and so on...

[ChefCrash]

I don't see why it wouldn't work. It's a bit pricey, I've seen units like that for about $50.

If you decide that sous vide is not your bag of chips, the unit will come handy for many thing:

Controlling a space heater in the winter.

Controlling a cooling or ventilation fan in the summer.

Controlling temperature of a dedicated refrigerator for Lagering home brew or aging meats.

Controlling temperature in an electric smoker.

On the other hand, for about $45 and a cheap hot plate you could have PID control using this.

[andiesenji]

Here's a "vintage"

Westinghouse electric roaster, with all the parts.

I have two, one pink, one white, both with their original stands.

In case you want a bit more information

Click here!

Edited April 25, 2007 by andiesenji (log)

[s_sevilla]

just want to add my two cents:

I bought a polyscience unit off ebay for 175 (8L or so), although a little small, for a college student living with roommates its a perfect additition to my kitchen. It does not circulate, but for long cooked items, or individual servings, the temperature stays very uniform when the lid is closed, never dropping below 1 degree divergent from the set temperature. It definitely saves time to prep and freeze a portion of my dinners before hand, then drop stuff in before I go to class in the mornings. This is also by far the easiest and most economical way to confit meats. It may seem a little prohibitive when you first jump in, but the savings (at least as I see it) are well worth it, and the quality of food is great.

[jmolinari]

Joe Blowe, that shuold work well, but you could also get something similar for about $50, it'll just require that you do some wiring. It has a relay built in, but you need to wire plugs and connectors, and a thermocouple.

http://www.dwyer-inst.com/HTDOCS/temperatu...iesTCSPrice.CFM

jason

[Darcie B]

Here's a "vintage"

Westinghouse electric roaster, with all the parts.

I have two, one pink, one white, both with their original stands.

In case you want a bit more information

Click here!

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Thanks, Andie, for posting about these roasters. I scored one at an antique shop for $20 last year and thought it would be a good vessel for sous vide, although I expected to need a circulating immersion heater for it. I need to check the temp controls to see what the lowest setting is.

I have the original stand (with clock!) and inserts for it, and just sent the stand off to be powder coated since it was somewhat rusted. So I'll have $170 in it altogether.

[slkinsey]

The lowest setting on all of my vintage roasters, Westinghouse, Nesco, Hamilton Beach and GE, is 150 degrees F.

Unfortunately, 150F/65C is not particularly useful for extended sous vide cooking, and for shorter cooking times (e.g., for fish) it's unclear that these roasters offer any advantages over simply heating a large stock pot of water to temperature on the stove.

It's unclear to me that there is a reasonably unflawed solution for sous vide temperature control that exists between simply heating up a big stockpot of water to temperature and doing short-duration and waiting around for a decent recirculating water bath heater to come up on eBay for around 75 bucks (like this one). The problem with the other solutions is that the temperature regulation is too imprecise, or doesn't offer the desired range of temperatures, or is likely to have some spots hotter than others, or is likely to cycle up and down, etc. For most long duration sous vide cooking, these are all important considerations. For short duration sous vide cooking, a big stockpot and a thermometer will do just as well as anything short of a laboratory recirculating water bath heater.

[andiesenji]

Here's a "vintage"

Westinghouse electric roaster, with all the parts.

I have two, one pink, one white, both with their original stands.

In case you want a bit more information

Click here!

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Thanks, Andie, for posting about these roasters. I scored one at an antique shop for $20 last year and thought it would be a good vessel for sous vide, although I expected to need a circulating immersion heater for it. I need to check the temp controls to see what the lowest setting is.

I have the original stand (with clock!) and inserts for it, and just sent the stand off to be powder coated since it was somewhat rusted. So I'll have $170 in it altogether.

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I have had a couple of mine powder-coated. Although the Ham. Beach stand was in excellent shape, while the roaster itself was harvest gold with black trim, the base cabinet was black with gold trim. That black enamel showed every single fingerprint (and nose print from the dogs) no matter what I did to clean it. too, too frustrating. It is now sitting in the garage, sanded down to bare metal, ready to go off to be powder-coated a shaded harvest gold to match the roaster. It had chromed handles that were a little pitted, and they have already been re-chromed. The guys at the shop bought a roaster of their own after doing the work on mine a few years back. They cook barbecue, beef, chicken or pork, and some terrific chili. They have about a dozen employees, and apparently having free food keeps them happy, because the same guys have been there for several years. Before I took my old roasters in, they had never seen one in operation.

I stopped to pick up a vintage aluminum-shell picnic cooler last summer and they had the roaster full of corn on the cob one of the guys picked that morning. Delicious!

Slkinsey

As far as the water temp is concerned, I know the theory but there is more than one way to skin a cat, so to speak.

a physical barrier can be a simple way of reducing the temp of the water in which the bags are submerged.

I have prepared "scrambled" eggs for a huge crowd, cooked entirely and held for serving, in plastic bags that were in turn in water, in a covered Pyrex roaster that was resting on the rack in the roaster liner.

These old roasters do NOT have coils in the bottom, they wrap around the outer chamber. The lids fit tightly enough that there is little evaporation, in fact, to reduce liquid one has to turn the roaster up and remove the lid or in some, open the vents in the lid.

I have a gas cooktop and there is no way I will go off and leave an unattended stockpon or anything else on a gas burner. I live in earthquake country, I don't take chances with fire.

Edited April 26, 2007 by andiesenji (log)

[slkinsey]

Andie, I'm not saying that these roasters have no usefulness at all. I am simply saying that they have very limited usefulness for someone who would like to do real sous vide cooking, especially if they want to take advantage of the full range of things that make sous vide and interesting and unique. That's simply a fact. This is, after all, a thread about laboratory water baths for use in sous vide cooking.

[Darcie B]

The lowest setting on all of my vintage roasters, Westinghouse, Nesco, Hamilton Beach and GE, is 150 degrees F.

Unfortunately, 150F/65C is not particularly useful for extended sous vide cooking, and for shorter cooking times (e.g., for fish) it's unclear that these roasters offer any advantages over simply heating a large stock pot of water to temperature on the stove.

It's unclear to me that there is a reasonably unflawed solution for sous vide temperature control that exists between simply heating up a big stockpot of water to temperature and doing short-duration and waiting around for a decent recirculating water bath heater to come up on eBay for around 75 bucks (like this one). The problem with the other solutions is that the temperature regulation is too imprecise, or doesn't offer the desired range of temperatures, or is likely to have some spots hotter than others, or is likely to cycle up and down, etc. For most long duration sous vide cooking, these are all important considerations. For short duration sous vide cooking, a big stockpot and a thermometer will do just as well as anything short of a laboratory recirculating water bath heater.

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I plan to get an inexpensive PID controller ($35) and probe ($10) that will allow me a greater range of control on the temp in the roaster. I will wire it in in place of the standard temp controller. I can hide the controller in the stand and snake the probe up the back of the oven so it will look just like an ordinary roaster. Then I will have a stand alone sous vide operation with precise temp control. I think the roaster will be an ideal vessel for this operation and less expensive and cleaner than a used lab water bath that has been stuck in who knows what.

I am new at this and if I am missing something important please point it out to me. It seems like it should work.

[alwang]

It's unclear to me that there is a reasonably unflawed solution for sous vide temperature control that exists between simply heating up a big stockpot of water to temperature and doing short-duration and waiting around for a decent recirculating water bath heater to come up on eBay for around 75 bucks (like this one).  The problem with the other solutions is that the temperature regulation is too imprecise, or doesn't offer the desired range of temperatures, or is likely to have some spots hotter than others, or is likely to cycle up and down, etc. 

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I believe the Lauda heater in your eBay link is thermostat-controlled, which means it will also suffer from large temperature fluctuations. To get a PID-controlled circulator on ebay, you'll probably have to spend closer to $150-$200.

[slkinsey]

I plan to get an inexpensive PID controller ($35) and probe ($10) that will allow me a greater range of control on the temp in the roaster. I will wire it in in place of the standard temp controller. I can hide the controller in the stand and snake the probe up the back of the oven so it will look just like an ordinary roaster. Then I will have a stand alone sous vide operation with precise temp control. I think the roaster will be an ideal vessel for this operation and less expensive and cleaner than a used lab water bath that has been stuck in who knows what.

I am new at this and if I am missing something important please point it out to me. It seems like it should work.

What you'll be missing is the recirculating part of the deal, which serves to make sure that all the water in the vessel is at the same temperature. Depending on where the heat is coming from, it's possible that there could be fluctuations of several degrees depending on where you place the probe. Also, it's not clear to me that you're saving too terribly much money. How much are you going to spend on the roaster? You say your spent 20 bucks on the roaster, then there's another 45 bucks for the PID controller and probe, assuming those are reasonably accurate prices. For ten more dollars you could buy that Lauda B-1 recirculating heater and use it with a large stock pot you already own (or even a large plastic bus bin or pickle barrel). It's not clear from your earlier post whether you spent as much as $170 refurbishing the roaster. If you did, you're spending more money to have something that at best I think would be not quite as good as using a real recirculating water bath heater. To compare: If you spent, say, 100 bucks on a recirculating water bath heater and 30 bucks on a 16 quart stainless stockpot at Target, you'd have spend less money, you'd have something that works better, and you'd have a kickass stockpot that could be used for many other things.

I believe the Lauda heater in your eBay link is thermostat-controlled, which means it will also suffer from large temperature fluctuations.  To get a PID-controlled circulator on ebay, you'll probably have to spend closer to $150-$200.

To the best of my knowledge, ths Lauda B-1 recirculating water bath heater controls to within less than 0.5 degrees C. If one is patient, deals on even more recent model recirculating water bath heaters come up on eBay and elsewhere.

[Darcie B]

What you'll be missing is the recirculating part of the deal, which serves to make sure that all the water in the vessel is at the same temperature.  Depending on where the heat is coming from, it's possible that there could be fluctuations of several degrees depending on where you place the probe.  Also, it's not clear to me that you're saving too terribly much money.  How much are you going to spend on the roaster?  You say your spent 20 bucks on the roaster, then there's another 45 bucks for the PID controller and probe, assuming those are reasonably accurate prices.  For ten more dollars you could buy that Lauda B-1 recirculating heater and use it with a large stock pot you already own (or even a large plastic bus bin or pickle barrel).  It's not clear from your earlier post whether you spent as much as $170 refurbishing the roaster.  If you did, you're spending more money to have something that at best I think would be not quite as good as using a real recirculating water bath heater.  To compare:  If you spent, say, 100 bucks on a  recirculating water bath heater and 30 bucks on a 16 quart stainless stockpot at Target, you'd have spend less money, you'd have something that works better, and you'd have a kickass stockpot that could be used for many other things.

Thanks for the info.

I already had the roaster and refurbished it so it will look good in my retro 50s kitchen I am planning (downstairs kitchen). Originally I planned to use it for a warming drawer and perhaps even for its intended purpose(!). So I am not out any money I didn't originally plan to spend. And I surely didn't have to powder coat the stand in order to use it; that's just my OCD coming out

I could probably get an aquarium pump for the recirc part and as Andie pointed out, the coils go up and around the entire roaster so the heat is pretty evenly applied and convective currents keep it circulating. I'll know more when I measure the temps in different areas.

So at $20 for the roaster, $45 for the controller and probe (I got the prices from a link on another sous vide thread and they seem accurate), and maybe $10 for an aquarium pump (bet I can get one free), I'm still doing good cash-wise. Plus I don't have to find a place to put the stockpot since this has its own stand. And it looks cool.

I might get a recirc water bath heater if I can find a good enough deal; I haven't seen any for under $200. But I will likely still use the roaster as the vessel since I have it and it's convenient. Plus I feel it will retain the heat better than a thin stockpot. The stand probably won't come back for a few weeks so I have time to do some looking around. I have a friend who works in a lab sniffing around for surplus equipment too. Who knows, I might score a freebie!

[jdanton]

I just bought a Fisher IsoTemp 730 off of eBay. I tried to use it today, and the circuit breaker switch on the back keeps tripping. Anyone out there have any ideas??

Thanks.

[derekslager]

Based on the advice in this thread, I purchased a new water bath on eBay for cooking sous vide. It's an enclosed circulating bath, as advised for minimizing water loss with long cooking times.

The particular model I purchased has a 13L tank (about 3.5 gallons), just above nathanm's 10L recommendation. This ends up being a very nice size for home use, but would probably be too small for turning out restaurant quantities of food. Even being on the lower end of the capacity range, it takes quite some time (30-60 minutes) to reach temperature. A larger bath would likely take even longer, and its additional capacity would rarely be taken advantage of in my kitchen.

This is a mid-range digital model, with a two line display showing the target temperature alongside the current temperature. Unit conversions and various other settings are accessible via the buttons on the front panel. An RS-232 control port enables more sophisticated programming and/or monitoring. More useful in a lab setting than in a kitchen, but nice to have nonetheless.

Here's a photo of the unit heating up with the lid removed:

The unit consists of two major pieces, connected with four screws. To get a good look at the heating element / pump, you need to take it apart. Here are some pictures of the individual pieces:

Bath:

Where'd the water go?

"Guts", side view:

"Guts", bottom view:

The heating unit hovers in the bath directly, so you end up with less capacity than the photo of the empty container would suggest. There is, however, enough clearance under the element to place food (for example, you could line the entire bottom of the bath container with eggs).

The "guts" don't look much different from an immersion style circulator. In fact, this could probably be used as an immersion circulator by positioning the top portion of the unit in a large hotel pan. I probably won't need that much capacity in my home kitchen, but it's certainly a nice option to have.

Overall, I would recommend a unit of this style for home use. It's reasonably compact (just a bit bigger than a rice cooker or deep fryer designed for home use), and it doesn't make a ton of noise (a low-to-moderate amount of vibration noise depending on its surface, and a rather pleasant babbling brook sound as the water circulates). The sous vide cooking process is so "hands off" that you could keep it in a bedroom closet if you were short on space.

These do tend to be a bit more expensive than immersion style units (the unit shown here retails for $2,600), but with some patience you can find one on eBay without breaking the bank. Mine was new (with some relatively minor cosmetic damage), and I paid less than $400 for it.

[bigcat39]

I work on laboratory equipment for a livivng, I second the reccomendation for the above unit. Durable, and fairly cheap to fix, the control and display boards together were ~$400. Very accurate, the display is within 0.04 deg. C, stability better than 0.009 C (standard deviation over 4 hours)

[zEli173]

Does anyone know if the heater/circulator portion of circulating baths is typically removable so it can be used like a stand alone immersion circulator? Obviously there are different types of baths, but I'm talking about the kind that basically look like the immersion circulator is self contained, like the one derekslager just bought.

It seems like some of the enclosed baths are going for for less on ebay than the immersion circulators. But living in a small Manhattan apartment, an immersion circulator is a more attractive option.

Fast response would be appreciated.

Edited February 21, 2008 by zEli173 (log)

[TheSwede]

I think they are almost always removable. You will have to find a way of fastening the unit to a pot though, and the models with a shallow immersion part (like the one above) would need a very full pot.

[zEli173]

So if it's removable, should I expect that the power cord goes directly into the circulator/heater rather than somewhere within the bath. In other words, I want to completely discard the bath. Can I?

[sygyzy]

So if it's removable, should I expect that the power cord goes directly into the circulator/heater rather than somewhere within the bath.  In other words, I want to completely discard the bath.  Can I?

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Yes