Sous vide – what to buy or ask for, for Christmas?

[Robert Jueneman]

I suppose that like many regulars on eGullet, I get very annoyed by the poor quality of reviews of sous vide and sous vide appliances in the main stream media.

The problem is that the reviewers, who generally have very limited if any experience in sous vide cooking, are trying to do two things at the same time — try out sous vide cooking for the first time, AND try out a sous vide appliance.

Since the reviewers have practically no experience in sous vide cooking, how can they possibly know whether their good (or bad) results are due to the appliance, luck, or their own ineptitude? Do they even have some basic recipes or books, such as those by Douglas Baldwin and others, much less those by the professional chefs, such as Heston Blumenthal, Thomas Keller, or Ferran Adria?

I have yet to read a review that talks about the desirable size or shape of such an appliance, much less a measurement of the accuracy or consistency of the water bath.

But I really think that those of us who have been cooking sous vide for 5 years or more, and have tested and own innumerable sous vide rigs (I’m now up to nine!) need to do more to supplement the reviews in the main stream media, so here goes.

I recently had an opportunity to calibrate a Sous Vide Supreme the other day, and found it to be off by over 2 degrees F. But do any of the reviewers even have a decent reference thermometer with which to calibrate such a device — even a very inexpensive basal thermometer? Not that I’ve seen yet. :-(

Now, as to the cost issue. Most reviewers seem to think that a sous vide apparatus costs around $1000 or more, and maybe that’s true if you are talking about a top-of-the-line professional PolyScience unit. And yes, if you throw in a $2000 to $3000 for a top of the line chamber vacuum, that’s adds a lot more to the cost. Pretty soon you are talking about what a high grade camera costs! All things are relative, I suppose.

But for some reason, the low cost options aren’t being discussed. Maybe that’s because the Sous Vide Supreme manufacturers and others are giving away their units to reviewers And it’s tough to “sell” a beer cooler and a Ziploc bag and the Archimedes principle!

So in the interest of informing the newcomers who might be interested in trying sous vide, I thought I would put together a minimally expensive "kit" of appliances and other essentials, one that you can put under the tree without breaking the family budget, yet will do nearly everything that might be reasonably expected.

The norm for kitchen stores seems to be an integrated appliance, but a much less expensive approach would be to use a PID controller such as the Sous Vide Magic from Fresh Meals Solutions (www.freahsmealssolutions.com), together with some kind of an electrical heating appliance. The Sous Vide Magic costs only $159.50USD, and that includes shipping to anywhere in the US or Canada.

Now, almost everyone probably has some kind of a electrical slow-cooker or perhaps a rice cooker, and if they don’t, an inexpensive coffee urn is a nice alternative. I recently found a 30 cup, 7 liter coffee urn at Home Depot that costs only $29, and it includes a handy drain when you are through cooking. http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?productId=100676080&storeId=10051&langId=-1&catalogId=10053&ci_sku=100676080&ci_kw=%7bkeyword%7d&kwd=%7bkeyword%7d&cm_mmc=shopping%2d%5f%2dgoogleads%2d%5f%2dpla%2d%5f%2d100676080&ci_gpa=pla#.UMIk1EIQH0A.

At the other end of the scale, a 100 cup urn is also a viable solution for $80, for those who need a slightly bigger appliance. http://www.amazon.co...4669752&sr=1-16 .

And Hamilton Beach has a 6-qt slow cooker for $19.88 at Wal-Mart, http://www.walmart.c...Cooker/16913519.

Now, would any of these devices hold an entire brisket, so you could cook it for 72 hours? Probably not, unless you cut it up. But would it be sufficient for cooking a medium size steak or corn on the cob, or other smaller portions for a small family? Certainly yes, and even if you had one of the larger, more professional units, that combination might be a nice unit to have on hand when cooking a second dish.

Now, what about sealing the sous vide bag? Contrary to what some might have you believe, a vacuum sealer is not absolutely necessary, although admittedly very convenient. You can use a simple Ziploc bag and the Archimedes Principle -- simply immerse the bag containing your food in water until nearly all of the air has been squeezed out, and then seal it.

On the other hand, if you want an inexpensive vacuum sealer, the Reynold’s Handi-Vac costs only $21.49.

So the bottom line is that a perfectly fine sous vide rig (the Sous Vide Magic, the 6-qt slow cooker, and a Reynolds Handi-Vac) can be had for about $200US!

Now, what if you want something a little more larger, either for a larger family, or for professional applications? The Fresh Meals Magic, also from Fresh Meals Solutions, is a more advanced unit that includes a heater and air bubbler for $149.50, plus $159.50 for the Sous Vide Magic controller. And a recently introduced variant of that unit with a new 1500E controller, the eiPOT (for eco-friendly, intelligent, POT (Plain Old Pot), is now available for $399.50. And as a special offer, eGullet readers are offered a $40USD discount for the eiPOT, bringing the price down to $359.50 through Dec. 16th. Mention coupon code SVMEG001E for eGullet readers!

The major convenience feature that the other units offer, such as the Sous Vide Supreme, is the fact that the temperature probe is integrated and hidden away, as opposed to the Sous Vide Magic controllers. Of course, that makes it more difficult to replace thew probe if it becomes necessary, so that’s a trade-off that has to be considered.

But the heating apparatus isn't the only thing that is needed, especially for those who are just starting out.

A decent sous vide cookbook, with elementary recipes, would certainly be useful, and I would highly recommend "Sous Vide for the Home Cook" by Douglas Baldwin, the pre-eminent author of sous vide technology, and especially all of the food safety issues. And his web contribution, http://www.douglasba.../sous-vide.html, is invaluable and free!

A reference thermometer is essential for calibrating your sous vide equipment. I recommend an inexpensive digital basal or ovulation thermometer, which should cost less than $20. Try to find one that isn't made in China, if you can.

And finally, Darren Vengroff's Sous Vide Dash app for the iPhone is extremely useful, if not essential. Even if you don't a have an iPHone, buy one for that for that app alone, as I did! It calculates the time and temperature required to cook an amazing number of different foods

I hope that this has been helpful. I'll monitor this thread, in case there are any questions.

Bob

[gdenby]

Good post. I've started saying "water bath cooking" instead of sous vide, because sous vide is strongly associated w. expensive equipment. And, lots of people say "sous what?" As you point out, good results can be had w/o the best vacuum.

[IndyRob]

I use a Presto Kitchen Kettle (now Multi-Cooker) which can be had for as little as $30. It can sous vide (with some fiddling), but it can also slow cook, steam and deep fry.

At the extreme low-end, I'm intrigued by the possibility of using a Crock Pot Lunch Crock ($20) and a ZipLoc manual vacuum pump ($5). I have the former and have just done some simple experiments with water so far. There's no temperature control (it's meant for just warming food) but it seems to hold a temp of about 160 with the lid on. Less with the lid off. Its small size and handle opens up the possibility of sous vide-ing your lunch on your desk at work.

[Robert Jueneman]

160F/71C is of course too high for most sous vide applications involving meat, except possibly for well-done chicken, and too low for vegetables.

But you could use that with a Sous Vide Magic or other PID controller to control the temperature.

Now, what your boss is going to say when you bring out your torch to sear your hamburger at your desk, that's a different story!

BTW, I should have mentioned the use of a torch in my list of recommended equipment. The alternative would be to use a cast iron pan with some high-temperatruwe oil, such a grape seed oil to sear the outside of most meat products.

[StevenHarris]

Thanks for starting this thread, it's long overdue.

I have been using the Auber Instruments WS-1500ES ($147.50), which near as I can determine is the same unit as the Sous Vide Magic. I plug in an Adcraft FW-1200W (about $100) food warmer. An aquarium air pump was used initially but it proved too noisy (to my wife, didn't bother me) so I discontinued it. Seems to cook fine without it.

I did experience some minor trouble with the Auber unit, but the customer service was excellent and I was back up and running shortly.

The Food Warmer is rather large but doesn't weigh much empty and the amount of water provides for very stable temps. There is a half size food warmer availible, but it seems to cost twice as much as the larger one. One advantage to the Adcraft is in other areas such as cheese and beer making. It takes standard food service pans that come in a wide range of sizes and shapes.

A vintage Food Saver vacuum packer rounds out the kit. I tend to only vac-pack larger expensive items and simply use a ziplock for most other things.

Thermoworks has a very nice unit with the "Therma K model 221-041" ($99) which I use a my refenence standard.

I've been doing water-bath-cooking for about a year and I can't imagine cooking meat any other way (I mean it!!).

I've used my propane torch occasionally but generally perfer a very hot gas broiler.

Take the plunge, get started, I believe you won't regret it.

Steven

[Icanmakeit]

Sorry, I am old school but this method of boiling food in bags escapes me and doesn't sound appetizing at all.

[rotuts]

no boiling involved, none at all.

uniform cooking based on your temp selection throughout.

[nickrey]

Sorry, I am old school but this method of boiling food in bags escapes me and doesn't sound appetizing at all.

If you have eaten out at high level restaurants, there is a strong chance that you have already had this form of cooking and not known it. It is now used routinely and not stated on the menu. I'm pretty sure they wouldn't use it if it wasn't appetising.

[Robert Jueneman]

OK. My first post on the subject concerned the equipment that someone might want to have, based on my experience, and was offered in part to counteract the rather uninformed "reviews" you find in the media.

But perhaps I should have also tried to summarize the benefits of sous vide cooking, for those who have somehow missed the last umpty-thousand posts on the subject on eGullet. or, like Icanmakeit, have a faulty impression of what is involved.

Like Steven Harris, I almost never cook meat (with the exception of fried bacon) any other way, and haven't for the last five years or so. Not only does sous vide provide a uniform cooking (no more "bulls-eye" effect on your steaks), but it gives you considerably greater latitude as to how long you cook your meat. Now, how long you cook something is very much a function of the thickness -- the time goes up with the square of the thickness, for most cuts, but once the meat has reached the temperature of the water bath, it won't get any more done. So you can cook a 25mm rib-eye for 1:35 at 53.5C/128F to reach a rare state, or you can cook it for 4 hours, and the results will be virtually the same. You can then sear it in hot oil, or with a torch, or on the grill, to get the nice Maillard reaction and crust on the outside edges.

So depending on what you are doing, this gives you greatly increased latitude. If there is a chance that you might be a little late coming home from work, you can have your spouse or even one of the kids throw a frozen, already bagged steak in the water bath at 4:00PM, and then eat it anywhere from 5:30 to 9:00PM with great results. And for restaurants, the increased flexibility is a godsend -- that's why everyone from Thomas Keller down to the Chipotle Grill is using it -- you don't have to have years of experience to get great results, and the food can be ready almost immediately.

For somewhat tougher but flavorful cuts of meat, you can cook a chuck steak for 24 hours at 55C/131F, and the long time/low temperature cooking will have the effect of softening the connective tissues while not overcooking the meat. The result will be as tender as a filet mignon, but still medium rare. Or to go to the extreme, cook a brisket or short ribs for 72 hours at 55C. The result will still be medium rare, but the meat will be fork tender, and much better than you would get a your local BBQ.

Finally, for those individuals who might be at risk (children, pregnant women, and those whose immune systems may be compromised) cooking meat sous vide provides a way of completely killing any harmful bacteria, such as e. coli, listeria, or salmonella, without overcooking it. I hate restaurant hamburgers, because are invariably over-cooked in order to be safe. But I can cook 20mm hamburgers sous vide for 2 hours at 55C and be assured that all of the bacteria that might have been brought into the interior of the meat when it was ground has been completely and thoroughly killed, and yet the burger is still pink and juicy. A brief sear, and it is perfect.

Vegetables also benefit from sous vide cooking, because the flavor isn't leached out into the hot water that is normally used, for example when cooking asparagus or corn on the cob. The time is a little more critical in this case, because in general you are cooking at a higher temperature, but corn on the cob cooked with some lime juice and chipotle powder for 30 minutes at 63C is superb.

Fish is also excellent when cooked sous vide, but in general the temperatures are lower, and the time is more critical. "Eat fish quickly, before it eats itself!" But if you want to impress/shock your guests, try cooking salmon at 40C/104F in your hot tub, while you are sitting in it! It will take about a hour.

Eggs cooked sous vide add a whole new dimension. Technically, they don't really need to be cooked "sous vide," i.e., in a vacuum bag, because they are in the shell, but the precision provided by the water bath, and particularly the possibility of combining two different temperatures and times provides results that simply aren't obtainable any other way. Cf. my blog on the perfect egg, at http://freshmealssolutions.com/index.php?option=com_k2&view=item&id=65:search-perfect-egg-jueneman&Itemid=100088.

I hope this helps to convince the doubting Thomas's. If not, I'll yell louder!

[IndyRob]

160F/71C is of course too high for most sous vide applications involving meat, except possibly for well-done chicken, and too low for vegetables.

But you could use that with a Sous Vide Magic or other PID controller to control the temperature.

Brined chicken or pork might work at 160, but as I mentioned, if you leave the lid off the temp is lower (I just don't have the numbers so didn't post guesses). But even so, it could still be successful if you watch the time. Cooking at 160 SV is still more controllable than traditional methods.

Now, what your boss is going to say when you bring out your torch to sear your hamburger at your desk, that's a different story!

Ha! I chuckled at that thought as I was posting. But apparently, some people like to do the sear-first method. I know I get a better sear when doing it first in a traditional method vs. searing after SV, but I've never tried sear-first and then SV.

[lsmith]

I agree entirely with the basic kit described here, particularly about the necessity of a calibration thermometer.

Without it, you really should steer clear of temperatures below about 56.5°C, since your controller could easily be out by a couple of degrees. And some of the best things that sous-vide can do happen around 54 or 55.

Since I'm a complete cheapskate, but am careful and have lots of patience, I took an old-fashioned approach to calibration, by buying a $30.00 laboratory mercury thermometer, accurate to 0.1°C.

Unlike a digital thermometer, it has no way of falling out of calibration, other than something disrupting the mercury column. There is one major caveat with this approach. These are very delicate indeed, and if you break one, you're facing a very significant spill of a highly toxic substance. You won't be able to use a Swiffer to clean up after that.

To just try out sous-vide, you can put off the controller for a while, but if you take to it, a controller will be in your future.

For the first year or so I cooked sous-vide, I didn't yet have a controller. I used an old (probably 1950s) thermostatically controlled deep fryer. Temperatures in the deep-fry range were written around the thermostat, but it would turn down all the way to room temperature. It would take hours of setting, measuring, and adjusting to set the temperature, but once set, it would regulate to within a couple of degrees, so it was useable.

As I said, though, you'll soon be asking Santa for a controller of some kind. Mine's one of the early Sous Vide Magic models, and it's still going strong. (I've gone through a few thermistors for it, but that's all it has needed)

[Joe Blowe]

I went through my bookmarks and realized that I've been tagging sous vide articles and sources since 2007.

And, I still don't own any SV equipment.

That changes NOW.

I have $110 worth of Amazon points available to me right now. That makes the SideKIC kind of no-brainer.

But, of course, there is FMS' SVM/FMM combo, which would allow me to significantly up-size my containers and portions. And, I wasn't even aware they had introduced the eiPOT(1500e)/FMM combo for just a few more bucks, as per the December 2012 offer. (BTW, I see their website still leaves a bit to be desired.)

What I do know is that I'm not going to DIY (for now), and I'm not going to buy another rice cooker, slow cooker, coffee urn, food warmer, or other "dumb" appliance. I don't mind using one of my Cambros or ice chests for SV, but I will not buy another so-called single-purpose electrical appliance. That rules out buying just a controller -- it's time to go all in.

What I don't know is what will suit me over the long-term. It's easy to believe the SideKIC and an ice chest would keep me happy in the near-term, but will I soon regret buying a "gadget" that may have a shorter lifespan than a PolyScience, Swid or SVM/FMM unit? (Looking at the big picture here, I know we're all guinea pigs testing early versions of SV equipment...)

So, tl;dr, buy a SideKIC for cheap, or spend a couple of hundred more on something that might last quite a bit longer?

[Martin Fisher]

Wow!

Excellent thread!

I've decided to take the sous vide plunge and happened to stumble upon this thread tonight.

The timing couldn't have been more appropriate.

Can someone recommend a good affordable reference thermometer?

Thanks!

~Martin

Edited December 10, 2012 by DiggingDogFarm (log)

[pbear]

Frankly, I don't think what has held back sous vide is the equipment reviews. Rather, based on conversations with friends, the problem is that it's generally perceived as one of those complicated techniques that high-end restaurant chefs use (and a few lunatic foodies). Even if they see the advantages - some do, some don't - the game doesn't seem worth the candle to the typical home cook. (The visceral objection to cooking in plastic also plays a role, like it or not.) And, if they perchance take an interest and do some research, they find a lot of disorganized information, conflicting opinions and few clear cut answers.

For example, I respectfully disagree about the recommendation of a PID-controlled slow cooker over the Sous Vide Supreme.. I have both. I use the former more (mainly for long cooks of big pieces of meat), but would recommend the latter to almost anyone interested in jumping in. Yes, it's more expensive. But not unreasonably so, much more versatile and easier to use (subject to the caveat about calibration). I agree about using ziplocs over a Food Saver (a chamber sealer being much too expensive for most people, me included), but many sources argue the contrary. Ditto cooking times, searing techniques, etc. Confronted with this cacophony of voices, most folks (even if they had an interest) throw in the towel and stick to the tried-and-true methods they've been using for years.

Maybe this will change eventually, but I'm beginning to have doubts. Seven years ago, I thought sous vide was going to be the next big thing. Unfortunately, the mainstream media (cooking shows and magazines) haven't embraced it, so it remains an oddity and an outlier. To an extent, this is a chicken-and-egg problem. So long as only a few use sous vide, the mainstream outlets will hesitate to give it much play. So long as it gets little play, sous vide has little chance of entering the mainstream.

What we early adopters can do to advance the cause, ISTM, is mainly to make the case for why we go to the trouble. How to do it, i.e., the equpment issues, should be the tail to the dog.

[PedroG]

Wow!

Excellent thread!

I've decided to take the sous vide plunge and happened to stumble upon this thread tonight.

The timing couldn't have been more appropriate.

Can someone recommend a good affordable reference thermometer?

Thanks!

~Martin

See wiki.egullet.org/index.php?title=Reference_thermometer and wiki.egullet.org/index.php?title=Sous_vide#Thermometers_and_their_calibration.

[Robert Jueneman]

Attached is a list of thermometers I've tested, but unfortunately only one of each. Unfortunately, I don't have current prices on them.

Sous Vide thermometers.pdf

Edited December 10, 2012 by Robert Jueneman (log)

[Baselerd]

Good post! It is a shame that all the reviews for SV equipment are generally rolled into an evaluation of the entire technique (usually) by those who aren't necessarily the target audience.

I have been cooking SV for about 2 years and I have only been using the Ziploc hand pump vacuum sealer. Even cheaper than the Reynold's one and doesn't convey the mental barrier of requiring an additional appliance. Not good enough to compress fruits/veggies, but good enough for just about everything else.

[Robert Jueneman]

For example, I respectfully disagree about the recommendation of a PID-controlled slow cooker over the Sous Vide Supreme.. I have both. I use the former more (mainly for long cooks of big pieces of meat), but would recommend the latter to almost anyone interested in jumping in. Yes, it's more expensive. But not unreasonably so, much more versatile and easier to use (subject to the caveat about calibration). I agree about using ziplocs over a Food Saver (a chamber sealer being much too expensive for most people, me included), but many sources argue the contrary. Ditto cooking times, searing techniques, etc. Confronted with this cacophony of voices, most folks (even if they had an interest) throw in the towel and stick to the tried-and-true methods they've been using for years.

I didn't mean to specifically recommend one type of SV appliance over another. The Eades and their Sous Vide Supreme have done a great job of trying to advance the cause of sous vide, and I commend them for it; and so has Frank Hsu of Fresh Meals Solutions (www.freshmealssolutions.com -- I mistyped the URL on my first post); and the good folks at PolyScience as well.

The Sous Vide Supreme, like most such devices, needs calibration, but I would not naysay the convenience of having an integrated unit, vs. somewhat less expensive but arguably cluttered pot plus PID controller approach. That also applies to the more expensive but highly reliable PolyScience units. And I don't mean to overlook the SideKIC, SWID, and others, including the newer, less expensive PolyScience units now being sold by Williams-Sonoma -- I just don't have any personal experience with them.

As to the difference in cooking times, temperatures, pre- vs. post-searing, etc., I think that is endemic to cooking in general. Otherwise, we would all have Fannie Farmer's The Boston Cooking-School Cook Book from 1896, with its 1,849 recipes (which I don't have but ought to buy), instead of my entire 8' x 6' cabinet full of cookbooks.

[JBailey]

Aside from those of us who eGullet, there are many consumers being exposed to sous vide daily. Not just in restaurants or articles in magazines, but right in the aisle where they are grocery shopping. A few weeks ago, I purchased a leg of lamb from Cuisine Solutions at a local Costco. As you probably all know, Cuisine Solutions was the pioneer in sous vide and today offer a wide variety of sous vide prepared foods for both commercial and home use. Their preparation instructions on the bag give conventional oven directions and also how to prepare the leg of lanb in a water bath.

Sous vide seems to be moving from experimental food preparation to something to be found in more and more kitchens. This may be similar to how induction has been accepted and become increasing visible in home kitchens.

[Reignking]

Reinvigorated by Modernist Cuisine at Home, I'll finally be building this $50 version:

http://qandabe.com/2011/50-diy-sous-vide-immersion-heatercirculator/

[jorach]

I own a Sous Vide Supreme Demi and I think it has an inherent design flaw;

The inside of the unit is coated aluminum and it comes with a stainless steel bag rack and an aluminum bottom plate that the manufacturer says is important for conduction.

The problem is that the aluminum bottom plate corrodes. Mine is horrible looking and fills the water with floating white particles of some material that's coming out of the rack during the cooking process. Now the inside of the bath is starting to corrode.

I exchanged the bottom rack which didn't fix the issue. The manufacturer then replaced the entire unit and that didn't fix the issue. I'd be willing to take some blame for my tap water but it's happened at four separate apartments in two states.

I'd avoid the Sous Vide Supreme Demi. I only paid $199 for it on special so I'll use it until it corrodes a hole in itself and dies. The Sous Vide Supreme seems to have an internal steel bath and replaces the aluminum plate with a stainless plate which likely mitigates the issue.

[haresfur]

I own a Sous Vide Supreme Demi and I think it has an inherent design flaw;

The inside of the unit is coated aluminum and it comes with a stainless steel bag rack and an aluminum bottom plate that the manufacturer says is important for conduction.

The problem is that the aluminum bottom plate corrodes. Mine is horrible looking and fills the water with floating white particles of some material that's coming out of the rack during the cooking process. Now the inside of the bath is starting to corrode.

I exchanged the bottom rack which didn't fix the issue. The manufacturer then replaced the entire unit and that didn't fix the issue. I'd be willing to take some blame for my tap water but it's happened at four separate apartments in two states.

I'd avoid the Sous Vide Supreme Demi. I only paid $199 for it on special so I'll use it until it corrodes a hole in itself and dies. The Sous Vide Supreme seems to have an internal steel bath and replaces the aluminum plate with a stainless plate which likely mitigates the issue.

One thing you might try is insulating (in the electrical sense) the aluminium from the steel. You may be getting galvanic interactions causing the aluminium to corrode. Perhaps some silicon sheet between the two would help. Disclaimer: Only a theory, I haven't looked up the potentials involved and I don't know the unit to understand if this would be possible.

[Martin Fisher]

Since I don't have a lot of money to work with (lowly peasant farmer here), I was considering going with the $99 Dorkfood DSV, but it appears that the SousVideMagic 1500D HD is a better option and only $60 more when you factor in shipping costs.

~Martin

[Robert Jueneman]

Aside from those of us who eGullet, there are many consumers being exposed to sous vide daily. Not just in restaurants or articles in magazines, but right in the aisle where they are grocery shopping. A few weeks ago, I purchased a leg of lamb from Cuisine Solutions at a local Costco. As you probably all know, Cuisine Solutions was the pioneer in sous vide and today offer a wide variety of sous vide prepared foods for both commercial and home use. Their preparation instructions on the bag give conventional oven directions and also how to prepare the leg of lanb in a water bath.

Sous vide seems to be moving from experimental food preparation to something to be found in more and more kitchens. This may be similar to how induction has been accepted and become increasing visible in home kitchens.

Adding water bath instructions to commercially packaged products would do more than anything to help popularize sous vide, and a friendly note to manufacturers from avid consumers would probably help a whole lot, hint, hint.

Meanwhile, I'm saving up for an induction hob, to add to my collection of appliances. If i get many more, I may have to consider putting a spit in front of the fireplace, and hiring a young boy to turn it!

[PedroG]

I own a Sous Vide Supreme Demi and I think it has an inherent design flaw;

The inside of the unit is coated aluminum and it comes with a stainless steel bag rack and an aluminum bottom plate that the manufacturer says is important for conduction.

The problem is that the aluminum bottom plate corrodes. Mine is horrible looking and fills the water with floating white particles of some material that's coming out of the rack during the cooking process. Now the inside of the bath is starting to corrode.

I exchanged the bottom rack which didn't fix the issue. The manufacturer then replaced the entire unit and that didn't fix the issue. I'd be willing to take some blame for my tap water but it's happened at four separate apartments in two states.

I'd avoid the Sous Vide Supreme Demi. I only paid $199 for it on special so I'll use it until it corrodes a hole in itself and dies. The Sous Vide Supreme seems to have an internal steel bath and replaces the aluminum plate with a stainless plate which likely mitigates the issue.

One thing you might try is insulating (in the electrical sense) the aluminium from the steel. You may be getting galvanic interactions causing the aluminium to corrode. Perhaps some silicon sheet between the two would help. Disclaimer: Only a theory, I haven't looked up the potentials involved and I don't know the unit to understand if this would be possible.

You might omit the SS rack, place glass beads or marbles in the bottom of the bag to avoid floating and eventually suspend the bag on a skewer (you may have to cut two notches in the cover to allow for the skewer).