
For my final project I built a sous-vide immersion cooker - arbesfeld
http://fab.cba.mit.edu/classes/863.14/people/matthew_arbesfeld/2014/12/14/final-project/
======
cnvogel
Hey arbesfeld, I really like that project, and the nice writeup really
presents it well. But especially as people might use it for inspiration for
their own temperature-controlled cooking projects, I think the lack of a
proper isolation of the mains-powered parts is a little bit worrying.

For the next project, or maybe as advice to the random person looking at the
HN comments, here's what I normally do:

Try to minimize the area of unisolated conductors in devices on which you
work. If I solder cables to e.g. a mains inlet, I'd put heat-shrink-tubing
over it, so that it's not touchable anymore. Or use the proper crimped
terminations, which also are available in isolated versions.

[https://www.google.de/search?q=flachstecker&tbm=isch](https://www.google.de/search?q=flachstecker&tbm=isch)

To protect braided wire, and make the connections more reliable over time, I
like to use "wire termination" (I don't know the correct english term, in
Germany we call them Aderendhülse (literally: conductor end sheath).

[https://www.google.de/search?q=aderendhülse&tbm=isch](https://www.google.de/search?q=aderendhülse&tbm=isch)

Instead of these "screw on caps" for cables, try to find suitable terminal
blocks.

If you have the possibility to access a 3D printer, make a small clip that
goes over the screw-terminals of the solid-state relay.

If possible, try to have a "high-voltage" and a "low voltage" side in your
enclosure, that way, you are even less likely to come in contact with mains
voltage while working e.g. on the MCU part (connecting/disconnecting the
programming cable).

I'd like to stress again: I really like your project as presented, I only want
to show some ways in which the project could serve maybe as a inspiration also
to safe mains-powered electronic design.

~~~
arbesfeld
Thanks for the tips. This was my first time working with power components and
I wasn't familiar with most of these parts. I'll incorporate these suggestions
into the blog post so that they can be a resource to others.

~~~
mikeytown2
Recommending using a Wago [1] or Set-Screw wire nuts [2] for joining wires as
these are harder to use improperly than a wire nut. Video on how to use a wire
nut [3]; people mess these up all the time. For the mains voltage I recommend
using at least solid THHN 14 AWG wire, it's the minimum required wire size for
a 15 amp circuit (Most outlets are rated for 15 or 20 amps); color coded as
well, white for neutral & black/red for your hot, green for ground. If you're
unsure what one is hot, compare the voltage to the ground. A good clean design
should not require electrical tape for it to be safe if you take the cover
off.

Having a physical barrier between your low and high voltage areas is a must;
the low voltage wire used to switch the relay is the only thing that should go
inside the high voltage area (drill a small hole just for this wire & keep it
away from 120v as much as possible), also mount the plug for your 5 volt
source on this internal wall; or better yet use a USB outlet [4] as these are
designed to be ran inside an enclosure. Using color coded wire for the low
voltage is advised as well.

Since you're dealing with water, making this device GFCI protected would be
smart. Have your mains run through this first before anything else [5]. And
finally for the relay get one that is UL listed & opto-isolated in order to
prevent bad things from potentially happening; the RIBTE01B [6] will most
likely fit the bill. Be sure to check the ratings for your relays; putting
more power through them than they are designed for might end up with your
project in flames. If you're unsure about the power requirements, using a
small relay to turn on a big relay [7] is OK.

[1] [http://www.amazon.com/Wago-222-413-LEVER-NUTS-Conductor-
Conn...](http://www.amazon.com/Wago-222-413-LEVER-NUTS-Conductor-
Connectors/dp/B003K124UA)

[2] [http://www.amazon.com/Wire-Connector-Set-Screw-
Black/dp/B000...](http://www.amazon.com/Wire-Connector-Set-Screw-
Black/dp/B000LEZGEK)

[3] [https://www.youtube.com/watch?v=32z6Q8--
fEM](https://www.youtube.com/watch?v=32z6Q8--fEM)

[4] [http://www.amazon.com/Leviton-T5630-W-Tamper-Resistant-
Recep...](http://www.amazon.com/Leviton-T5630-W-Tamper-Resistant-
Receptacle-125-Volt/dp/B008O11IEY)

[5] [http://www.homedepot.com/p/Leviton-SmartLockPro-20-Amp-
Combo...](http://www.homedepot.com/p/Leviton-SmartLockPro-20-Amp-Combo-Slim-
Blank-GFCI-Outlet-White-R58-X7590-0KW/202026837)

[6] [http://www.functionaldevices.com/building-
automation/display...](http://www.functionaldevices.com/building-
automation/display.php?model=RIBTE01B)

[7] [http://www.amazon.com/Packard-C240B-Contactor-Pole-
Voltage/d...](http://www.amazon.com/Packard-C240B-Contactor-Pole-
Voltage/dp/B004Z0RLL2)

Edit: If you do end up keeping your solid state relay, ground the heat sink.

2nd Edit: If you want to avoid the need to 3D print the enclosure, using a 4
gang box [8] you could make this work. 1st slot is your input Single-Gang
Decor Recessed Power Inlet [9]. 2nd slot is the GFCI [5]. 3rd slot is the USB
outlet [4] with a cover [10] for your low voltage side. 4th is the outlet [11]
to your heaters. Drill a hole in the box for the relay [6] if it doesn't fit
inside as it is threaded and is designed to be externally mounted like this if
needed. Mounting some lights [12] is helpful to know if the device has power
and the outlets are powered. If you can find a larger gang device [13], you
can incorporate an simple switch to turn the whole thing on or off and maybe
mount everything inside.

[8] [http://www.homedepot.com/p/Carlon-4-Gang-68-cu-in-
Electrical...](http://www.homedepot.com/p/Carlon-4-Gang-68-cu-in-Electrical-
Wall-Box-B468R/202077406?N=5yc1vZbohnZ1z13rg0Z1z13vcj)

[9] [http://www.amazon.com/Midlite-MDT4642W-Single-Gang-Decor-
Rec...](http://www.amazon.com/Midlite-MDT4642W-Single-Gang-Decor-
Recessed/dp/B002XDQAA6)

[10] [http://www.amazon.com/Safety-Innovations-10408-Twin-
Outlet/d...](http://www.amazon.com/Safety-Innovations-10408-Twin-
Outlet/dp/B007IUOG5A)

[11] [http://www.homedepot.com/p/Leviton-15-Amp-Duplex-Outlet-
Whit...](http://www.homedepot.com/p/Leviton-15-Amp-Duplex-Outlet-
White-R52-05320-00W/202066670)

[12] [http://www.homedepot.com/p/Madison-Electric-Products-
Smart-B...](http://www.homedepot.com/p/Madison-Electric-Products-Smart-
Box-6-Gang-Multi-Mount-Adjustable-Depth-Device-Box-
MSBMMT6G/203343456?N=5yc1vZbohnZ1z0x750Z1z13rg0)

[13] [http://www.amazon.com/Indicator-Pilot-Signal-Light-
Cable/dp/...](http://www.amazon.com/Indicator-Pilot-Signal-Light-
Cable/dp/B008FY7146)

------
arbesfeld
Hi! Original poster here. I built this as part of the "How to Make Almost
Anything" class at MIT
([http://fab.cba.mit.edu/classes/863.14/](http://fab.cba.mit.edu/classes/863.14/)).
This was more of a weekend hack for fun than a money-saving project. Thanks
for all of the advice and comments!

~~~
tptacek
It's a great writeup!

~~~
blhack
I've seen you comment a lot on sous vide in the past, is there a specific
machine that you recommend?

(And then is there one you'd recommend if money was no object)

~~~
_pius
I own the Sansaire, but right now I'd recommend the new Anova one that comes
with an app and is well-reviewed by Serious Eats.

[http://anovaculinary.com/products/anova-precision-
cooker](http://anovaculinary.com/products/anova-precision-cooker)

[http://www.seriouseats.com/2014/05/new-anova-precision-
cooke...](http://www.seriouseats.com/2014/05/new-anova-precision-cooker-best-
cheapest-sous-vide-circulator-on-the-market.html)

~~~
mikecb
Do you know if they've released the android app yet? You can use it without
(has a little wheel to set temp), but the monitoring and timing obviously
don't work.

~~~
pfooti
There is an android app on the google play marketplace, but it is not from the
anova folks and it costs $2. I haven't purchased it, because I already have my
own list of "if you're cooking foo, set the temperature to bar" commands in my
(analog) recipe notebook.

Everything else about the newer anova is great. I have both a new-style and
old-style (anova one) from them, and they're both cool. Now that I have the
newer one with the adjustable clip, I intend to keep that in my kitchen for
simple sous-vide stuff (steaks, chops, eggs, etc) and build an insulated
enclosure out of a cooler for the One, so I can tackle bigger cooking
projects.

~~~
mikecb
Yeah, I'm really enjoying it as well. Have made some amazing eggs so far.

------
joezydeco
I'm curious to see a graph of actual temperature vs setpoint. You're doing
basic bang-bang control with a bunch of immersion heaters that get hot VERY
quickly.

And, dude, make that thing a little safer. Fuse your AC supply. Use real
crimped terminal connectors. Put a safety enclosure around those immersion
heaters or at least get them farther away from the wall of your chamber. Find
a better way to secure them than electrical tape.

And for $100 you can get a Dorkfood DSV from Amazon that will (safely) PID-
control a $10 crockpot. So there are cheaper alternatives than what you have
found.

~~~
tdicola
Agreed on the safety concerns, but I think the point of the project was
learning, not saving money.

------
dpeck
Great writeup, but we're probably past the point of DIY sous-vide systems
being anything more than weekend hacker project for funsies.

I just picked up an anova a few months ago (was $169 on sale) and for that
price you need to be getting a lot of enjoyment out of the build process and
be happy having an inferior product at the end.
[http://smile.amazon.com/Anova-Sous-Vide-Immersion-
Circulator...](http://smile.amazon.com/Anova-Sous-Vide-Immersion-
Circulator/dp/B00GT753W8/ref=sr_1_1?ie=UTF8&qid=1418667231&sr=8-1&keywords=nova+sous+vide)

------
scott_karana
> An average sous-vide cooker costs $2000, with low-end cookers going for
> around $300

Seems a bit exaggerated, and I'm not sure why, when this article was pretty
awesome otherwise.

The professional-grade, ubiquitous Polyscience MX units are around
~$1000[1][2], and the low-end cookers start at $180-200[1][2]...

1 [http://www.amazon.com/MX-Immersion-Circulator-C-
Clamp/dp/B00...](http://www.amazon.com/MX-Immersion-Circulator-C-
Clamp/dp/B007PB9DLO)

2 [https://www.instrumart.com/products/37038/polyscience-mx-
imm...](https://www.instrumart.com/products/37038/polyscience-mx-immersion-
circulator)

3
[http://anovaculinary.com/pages/products](http://anovaculinary.com/pages/products)

4 [http://sansaire.com/shop/](http://sansaire.com/shop/)

~~~
tptacek
It is way, way exaggerated. Even the professional Polyscience (the one I see
in restaurant kitchens) only costs ~$800. HN'ers shouldn't pay anything like
that: the current price point for consumer home circulators (the only kind you
should get, like the Anova or Nomiku or Sansaire) is ~$160.

~~~
nappy-doo
I was on the design team for the PS machines. (I say design team, I mean it
was three people in a room for the whole thing [circuits/software/mechanical
design].)

The main advantages of a high end machine are more accurate control (small
advantage) and circulation (big advantage). The linked article's control
algorithm is primitive (to say the least), and probably only marginally
maintains set temp. The PS machines are accurate to < 0.01 degree (which for
food doesn't matter), but the control software is the same between the food
machines, and high end chemistry equipment.

~~~
jimmaswell
As far as I can tell, some small waterproof fans would be more than enough for
sufficient circulation. Why is that a specific advantage of high-end ones?

~~~
nappy-doo
flow is very important with the temperature gradients that can exist in fluid.
When you're talking about 0.01 and 0.001 degrees, flow is really important.

~~~
001sky
Yes...the whole point of sous vide is this ....

------
tzs
I have a couple of questions about the schematic.

R4 and R5 are 0K resistors. 0K resistors actually exist, and are typically
used in place of short pieces of wire. The advantage of a 0K resistor over a
short piece of wire is that they can be picked and placed and soldered using
the same equipment that handles resistors, thus saving the need of having a
separate machine for short wires.

That is how they are being used here, as you can see from the layout diagram.
R5 is used to carry the RST signal over another line on the board, and R4
serves the same function for VCC.

First question: should these even be included on the schematic? They only
exist to work around a construction limitation due to the use of a single
layer PCB. If the circuit was built on a two layer PCB, or a breadboard, or
wire wrapped, there would be no 0K resistors needed. I thought that schematics
were supposed to just convey the topology of the circuit, leaving things
related to the practical difficulties of construction to other documents (like
the layout diagram).

Second question: on the schematic, why is R5 shown as connecting RST to RST,
but R4 is shown as connecting VCC to itself? They are both being used to take
a line across another line, so why aren't the both drawn the same way on the
schematic?

~~~
vonmoltke
A 0 ohm resistor typically is only used for places where a different-valued
resistor could be substituted or used to exist, or to act as an optional
jumper on different revisions of hardware. In those cases, the resistor is in
the schematics.

A circuit designed from the start with a 0 ohm resistor that was just used for
connecting two points across some board feature would never make it past
review where I used to work. Such a situation may come up due to later design
changes or board damage, in which case the board is modified by use of a "blue
wire", which is an actual blue-insulated wire that makes a point-to-point
connection on the surface of the board. Those are not in the schematic.

That said, I used to work on military electronics. Perhaps the consumer
electronics world is different.

------
surement
This is a nice project but this common misconception is false:

> Searing the food after sous-vide seals in the juices

[http://www.foodnetwork.com/videos/to-sear-or-not-to-
sear-985...](http://www.foodnetwork.com/videos/to-sear-or-not-to-
sear-98517.html)

~~~
IvyMike
It may not be about sealing in the juices, but a sous-vide steak out of the
bag is a very unappealing grey color. And the Maillard reaction is necessary
for proper taste. You need to do _something_ to it, be it throw it on a hot
pan for a minute a side or use a Searzall.

~~~
pfooti
The searzall has become an absolute necessity in combination with my sous vide
in the kitchen. I definitely do a post-sear, although I never really do a pre-
sear. I can see reasons people might want to, I should experiment now that
it's easier to do that.

------
ha292
Question for sous-vide aficianados. Are you not worried about the chemicals
going from plastic to your feed ?

I grew up knowing that, by and large, the less manufactured stuff you put in
your food the better the food is for your body.

So, it seems highly dangerous to me to take natural piece of food, wrap it in
a highly complex chemical compound (plastic), heat it, and then consume it.

~~~
maratd
Most of the time the food came in that very plastic. I mostly sous-vide meat
that came frozen and is already vacuum sealed. One less step.

You're generally heating it to 140 F or so. I don't know if that's sufficient
to trigger leaching of some sort, but the plastic isn't deformed in any way
and there's no aftertaste.

Any experts care to weigh in?

~~~
ha292
Is there any scientific evidence for this statement on no harmful chemical
transfer below 140F. Also, just because the food came in the very bag you're
cooking it in doesn't mean it is safer.

~~~
maratd
> Is there any scientific evidence for this statement on no harmful chemical
> transfer below 140F.

I didn't make that statement. I simply stated that was my practice. If you
have evidence that it is harmful, I would certainly like to know.

> Also, just because the food came in the very bag you're cooking it in
> doesn't mean it is safer.

Absolutely. There is no evidence that it doesn't leach at room temperature.
Should we stop buying all food packaged in plastics? That's a tall order. Many
vegetables come in plastics now and those that don't, you'll likely put in a
plastic bag either in the grocery store or as you're leaving it.

Do you have evidence that any of this is harmful? Genuinely want to know.

------
bitroliest
Not directly related to the tech, but "sealing in the juices" with a sear is
broscience. [1] [http://www.seriouseats.com/2009/12/the-food-lab-how-to-
cook-...](http://www.seriouseats.com/2009/12/the-food-lab-how-to-cook-roast-a-
perfect-prime-rib.html?ref=search)

~~~
scott_karana
"Sealing in the juices" is definitely false, but a hot sear to cause the
Maillaird protein reaction is important if you want to have the distinctive
"traditional" steak taste.

~~~
joshu
The more important question for sous vide: Sear before or after vacuuming? Or
both?

~~~
scott_karana
Dave Arnold tested this, and preferred searing before _and_ after cooking. :)

[http://www.cookingissues.com/primers/sous-vide/purdy-
picture...](http://www.cookingissues.com/primers/sous-vide/purdy-pictures-the-
charts/)

------
abakker
Or, instead of writing temperature control logic yourself, you can buy a
really cheap PID. There are nuances to good temperature control that warrant
using chips that optimize for the environment they are heating.

[http://www.instructables.com/id/Sous-vide-cooker-for-less-
th...](http://www.instructables.com/id/Sous-vide-cooker-for-less-
than-40/?ALLSTEPS)

Also, a PID is not a thermostat -
[http://en.wikipedia.org/wiki/PID_controller](http://en.wikipedia.org/wiki/PID_controller)

I'm sure that in water, a simple thermostat can be good enough, but its
probably still best to have a controller that optimizes for its environment. A
major point of sous vide is that the cooking temperature is very close to the
minimum pasteurization temperatures. Cooking steak at 137 degrees requires
that you are SURE it actually cooked at 137 for the amount of time you
specified. Also, 90 minutes for a steak is insufficient at 56°c

[http://www.polyscienceculinary.com/blog/food-safety-with-
sou...](http://www.polyscienceculinary.com/blog/food-safety-with-sous-vide-
cooking/)

~~~
arbesfeld
Great points, I do think that a professional PID is a better and more
efficient way to build a sous-vide. I wanted to build something from basic
components instead as part of the learning process, and also to allow me
customize the logic via Bluetooth.

Regarding the steak, I find that a 1 inch thick steak only takes ~45 minutes
to reach the target internal temperature. This scales dramatically as the
steak thickness is increased, however.

~~~
abakker
because the temperatures inside are below instant pasteurization temperatures
(158°F) though, reaching the target is insufficient. They need to be held at
the target temperature over a period of time to guarantee sufficient
pasteurization.

I'll also agree that the learning process can't be beat the way you did it.

I suppose you could simulate the PID function in software on the arduino
though -
[http://playground.arduino.cc/Code/PIDLibrary](http://playground.arduino.cc/Code/PIDLibrary)

~~~
jwr
Be careful with Arduino libraries. If you are trying to learn something, it's
usually better to write your own, or look at _really_ good code.

Case in point, PIDLibrary, I'm looking at the PIDCompute function, line 57:

    
    
          ITerm+= (ki * error);
    

That's not how you deal with I. You are supposed to accumulate (integrate) the
error and multiply by Ki only for the final PID addition. You don't want to
accumulate your errors multiplied each time by Ki, it makes no sense.

~~~
bradyd
That is actually done intentionally to allow for changing of the tuning
parameters while the PID is running.[1] The author of the PID library has a
full writeup on the design of the algorithm.[2]

[1] [http://brettbeauregard.com/blog/2011/04/improving-the-
beginn...](http://brettbeauregard.com/blog/2011/04/improving-the-
beginner%E2%80%99s-pid-tuning-changes/) [2]
[http://brettbeauregard.com/blog/2011/04/improving-the-
beginn...](http://brettbeauregard.com/blog/2011/04/improving-the-beginners-
pid-introduction/)

------
StavrosK
I love the "cost" table. Having recently built a mobile phone out of a rotary
phone
([https://www.youtube.com/watch?v=fSkdWQswpc8](https://www.youtube.com/watch?v=fSkdWQswpc8)),
my costs look something like those, except:

Cost of materials: $50

Time cost: $1500

Then again, it _is_ a prototype, which has to go with all the fixed costs, but
to say that this cooker only cost $X isn't entirely accurate.

------
vkatluri
This seems like a whole lot less effort and simpler design (of course without
the Bluetooth control). If some one is looking for a cheaper entry point, this
is great: [http://www.instructables.com/id/Sous-vide-cooker-for-less-
th...](http://www.instructables.com/id/Sous-vide-cooker-for-less-than-40/)

------
jedrek
Shouldn't water be flowing in a good sous vide cooker to maintain even
temperature throughout or am I talking out my butt?

~~~
arbesfeld
Yes, that is correct. I used an aquarium circulation pump for this
([http://fab.cba.mit.edu/classes/863.14/people/matthew_arbesfe...](http://fab.cba.mit.edu/classes/863.14/people/matthew_arbesfeld/img/final/final_cooking_eggs.jpg)).
They go for about 10 bucks on Amazon.

~~~
jedrek
Ah, I skimmed the article but didn't notice that. Thanks for your reply :)

------
NoNotTheDuo
I'd be curious to know how much the temperature fluctuates and what the
average temperature is, plotted against the target. A simple on/of setup like
this is much less complicated than a PID setup, but in my experience, the PID
code would allow for a much more accurate temperature to be maintained.

~~~
arbesfeld
In larger baths of water (I am using a half-filled 4.75 gallon container), the
temperature only fluctuates ~0.25C from the setpoint, as measured by the
sensor. I think the large quantity of water makes the change in temperature
very gradual.

~~~
jnellis
Your sensor says it's error is 0.5C. How was calibration done?

------
legohead
I've done some sous-vide after watching Chef Steps[1] on youtube. I just used
a water thermometer and ziplock bags, which they have some examples of in
their videos.

My smallest stove top burner at its lowest setting gets water up to 117F. The
salmon video they had the temp at 109, but I tried it anyway. It turned out
amazing - I'd definitely do it again. I also tried steak, but bought a cheap
cut, and it turned out really good as well. I turned the burner up to 2.5
which got the water temp to around 135F.

I'm so happy with my results I'm looking at purchasing a real sous-vide
heater. Sous-vide definitely has a bright future.

[1]:
[https://www.youtube.com/user/chefsteps](https://www.youtube.com/user/chefsteps)

~~~
eropple
I have a Sous Vide Supreme[1] and it's pretty much the secret weapon for
making cheap beef tasty. Even cheapo chuck can do really well in one of them
if you let them go for a while. What's nerdy-cool about it, I think, is that
if you're quick, you can seal a steak with no air bubbles whatsoever and the
steak will remain bright red while it cooks. Obviously you sear it after, but
watching people's eyes bug out a little when they see the bright red slab of
perfectly tasty and cooked meat come out of the pot is kind of amazing.

[1] - I also have an Anova, and if you can swing it I much prefer the SVS;
with the Anova the temperature gradient can be pretty wide in larger
containers, and you don't have to be nearly as careful about how you place
stuff in the SVS.

~~~
tptacek
Really? You're getting better performance from an SVS than an Anova? My
understanding is that for reasonable water baths, the Anova is pretty close to
the performance of the Polyscience, which is the gold standard. When Kenji Alt
tested the Anova, he found his unit had been miscalibrated; maybe check yours?

I donated my unopened Sansaire to Butcher & Larder and the first thing they
did with it was set it up in a _huge_ water bath to cook a bunch of huge
mortadella. It took them forever to get the bath up to temp, so long that I
thought something might have been wrong with the unit.

I think the fix was to cover the bath to eliminate evaporative cooling. That
is also a problem the SVS doesn't have, being a closed bath. But the
circulator should be more flexible and, from what I understand, higher
performance.

If you're willing to spring for the SVS, a better rec might be to go for the
mid-range Polyscience (the CS).

~~~
eropple
For my use cases, I find the SVS Demi (sorry, forgot to note that before) to
work well. I use it primarily for cooking for one or two people, on a daily
basis, so it does have a home on the counter and all. Setup/teardown (or just
having an ugly stockpot on the counter) makes the Anova worse for my use
cases, so I only break it out for big, 5-6 gallon batches of stuff, at which
point there is something of a temperature gradient at the far end of the bath.
I don't think it's a calibration thing, because it does work fine on smaller
batches, it's just not very useful to me there.

Also, I bought the SVS Demi on sale for under $300. The Polyscience bath is
like $500. (I got the Anova for free.)

------
bizzleDawg
My friend did a DIY Sous-vide towards the end of last year, no android app,
but has a simple UI for set point and tuning.

He actually made it a mains plug pass through (UK version) so that you can use
it with a traditional slow cooker for some temperatures etc.

Blog link: [http://rfwebb.com/projects/sous-vide-
part-2/](http://rfwebb.com/projects/sous-vide-part-2/) Extra pictures (Skip
all the PCB ones): [http://imgur.com/a/aG1Jp](http://imgur.com/a/aG1Jp)

Edit: source code: [https://github.com/bitdivision/sous-
vide](https://github.com/bitdivision/sous-vide)

------
Loic
For the readers, this is not a "sous-vide" cooker, only a temperature
controlled immersion cooker. "Sous-vide" means "in vacuum" and usually you
combine low temperature controlled long time cooking with low pressure.

A book from Thomas Keller about sous vide cooking:
[http://www.amazon.com/Under-Pressure-Cooking-Sous-
Vide/dp/15...](http://www.amazon.com/Under-Pressure-Cooking-Sous-
Vide/dp/1579653510)

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pepon
food + heat + plastics doesn't sound very appealing...

~~~
budgi3
This is what is holding me back on getting into sous vide. Any non plastic
alternatives?

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alkonaut
I fully expect plastics labelled with e.g "up to 90 degrees C" to not release
anything unwanted into my food if I stay well below that temp. I'd also expect
the label to have a wide margin to dangerous temperatures.

In theory you can use anything that handles the temperature, such as silicone.
You could in theory force your food into a jar with a bit of oil.

~~~
pflanze
You might be making matters worse with a jar: those with screw-on lids have a
plastic lining in the lid that's traditionally PVC with plasticizers which are
considered to be bad for health. To make matters worse, oil will support the
migration of the plasticizers out of the plastic.

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ojiikun
Pedantic: you built a really cool PID-controlled immersion heater, not a "sous
vide cooker". Sous vide is the technique of preparing food in a vacuum.
Placing food in a zip-top bag and displacing the air out might give you a
reasonable water-product interaction surface, but it does not form a vacuum,
and therefore is not cooking en sous vide.

~~~
joshu
Even more pedantic: The cooker doesn't generate the vacuum. You use an
immersion heater to cook the things in the bags.

It's also generally thought you don't really need to bother with actual vacuum
for meats anyway.

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nbardy
I'm curious on some numbers on how this performs compared to the commercial
units the expensive food industry models and the new kick starter wave.

Something like this could be really neat since it is versatile and you could
use it to heat/cool other things. Thinking about food the first time to mind
would be temperature control for charcuterie and cheeses.

~~~
tptacek
People already do stuff like this with PID-controlled temp and humidity, both
for curing meat and for barbecue. Auber Instruments makes controllers designed
for it, and they're pretty cheap.

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bliker
I was wondering why there is a need to involve a micro-controller? I can see
this project being done with couple of op-amps and potentiometer? I see so
many hobby project using arduinos for no good reason. Please people show some
love for analog electronics!

~~~
pbhjpbhj
> _why there is a need to involve a micro-controller?_ //

Easiest way to implement bluetooth?

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tgb
Sous-vide is interesting to me but only seems worth it if you eat a lot of
meat. Am I mistaken?

~~~
ghaff
You're not really mistaken. You can do some interesting things with eggs--very
precisely control the texture of both the white and the yolk (which relates to
the coagulation of different proteins). But, for the most part, I use sous
vide for meat and, especially, red meat. I'm not sure I'd say you need to eat
a "lot" of meat (it's not like I use my sous vide setup every few days) but it
is primarily for meat.

~~~
tptacek
It works really well with chicken thighs, too. :)

~~~
ghaff
I must say that I've never tried it with chicken thighs. I do use it with
boneless breasts now and then for when I want some cooked chicken for a salad
or noodle dish. It really helps keep the meat nice and moist while being
cooked just right.

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andr
I've never understood the need for a complicated sous-vide setup. I've found
that water at 80 degrees Celsius in a heavy pot with the lid on will remain
sufficiently hot for 30-45 minutes. If not, you can always swap the water
halfway through.

~~~
tptacek
That works fine for short cooks and for the most forgiving proteins, but it
does not work well for long cooks, braise cuts, vegetables, or high-temp
proteins (like confit). It's also much less convenient; you can bag proteins
and dunk them in the circulator in the morning and sear them when you get home
from work.

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gitpusher
Great project, and great write-up. But most people don't have access to a 3D
printer... which significantly changes the effective "cost" for such folks.
Still, thanks for sharing! Hope you enjoy all of that perfectly-cooked food :)

~~~
stephen_g
What's to stop somebody putting it in a $5 pre-made plastic box that you can
find at any electronics store?

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blackdogie
Looks great. I guess this would be a great time to think of maybe trying your
luck with Kickstarter (that is if you are interested in continuing working
with such hardware). Either way a nice write up for a cool little project !

~~~
tptacek
His BOM is just ~$60 off Sansaire's retail price, which is an integrated
circulator with performance near Polyscience's. This is a bad idea for a
Kickstarter: there is already an open price war between commercial-quality
circulators. They'll be under $100 within the next couple years (it's just not
that expensive to produce them.)

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pbhjpbhj
The point of sous-vide is [primarily] to break down proteins in meat?
Presumably then you can freeze the meat or refrigerate and simply re-heat/sear
at a later time?

Under this assumption are any stores offering pre-sous-vide meats?

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timinman
"Tape served as a lever for positioning the chip."

