66% or better

Precision Temperatures for Cooking or Whatever

sous-vide temp controller

If you have not heard of the sous-vide method of cooking you are not alone. This method uses a low temperature water bath to cook food in airtight plastic bags. Because the temperatures are much lower than normal the cooking time must be much longer and the actual temperature is very critical. The advantage is that the food is heated evenly without overcooking the outside. Since the food is bagged, it also retains moisture.

[Brian] put together a sous-vide control system to automatically maintain the correct temperature of a rice cooker. A temperature control unit was sourced on eBay for about $15. This is not a bad deal considering it has an LED display, control buttons, built-in relay and thermometer input. The control unit is mounted inside a project box with a few other components. The 120 volt AC line comes into the box where the neutral and ground are connected to the control unit and a standard outlet. The hot wire is connected directly to the control unit which determines if the hot wire is or isn’t connected to the outlet by using its built-in relay.

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Sous Vadar

sous-vader

[Craig] pulled off a beautiful build with his Sous Vader project. The name is a geeky spin on sous vide, a method of cooking foods in water held at a precise temperature. Building your own setup at home saves a ton of money, but it’s also a lot of fun. This explains the frequency with which we see these builds here at Hackaday.

So this one has a flashy name, a fine-looking case, but the beauty continues on the internals. [Craig] posted an image with the cover off of the control unit and it’s absolutely gorgeous inside. Part of the reason for this is the circuit board he spun for the project which hosts the ATmega328 and interfaces with the LCD, buttons, temperature sensor, and mains-switching triac. But most of the credit is due to his attention to detail. The image on the right shows him prototyping the hardware. Since some of his meals take 20 hours to prepare it’s no wonder he found an out-of-the-way closet in which to do the testing.

Make sure to read all the way to the bottom of the post for some cooking tips. For instance, since he doesn’t have a vacuum sealer he uses zipper bags — lowering them into water to push out the air as they are sealed.

A simpler sous-vide hack

Here are the contronl modules for a sous-vide project over at Nerdkits. [Humberto] and crew continue doing a great job of focusing a project on one goal, then explaining the steps needed to get there. In this case they wanted to build their own sous-vide appliance that was cheap, and didn’t really require the user to deal with mains voltage. We like it because most of the parts can be found at a hardware store and big box store.

He started with a slow cooker, which is pretty standard. Next he needed a way to switch power to the device. Instead of using a solid state relay, he went for a standard dimmer switch. It’s build into a double gang electrical box, and controls an outlet which is occupying the second position in that box. Now current to the slow cooker is limited by the position of the dimmer. The next task was to add a cardboard frame which marries a servo motor to the dimmer’s knob.

With the control scheme in place [Humberto] needed a feedback sensor. He built his own water proof temperature probe by covering an LM34 temperature sensor with shrink tube and sealing the ends. Just one probe in the cooking water isn’t very reliable so he added a second between the slow cooker’s base and ceramic vessel to improve the performace of the PID algorithm. He goes into detail about that in the video after the break.

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Testing an open source PID controller with steak

Sous vide cookers aren’t anything new, but [Phil] wanted to build the first sous vide using the osPID, an open source PID controller just released in the last month.

The build uses the osPID Open Source PID controller we saw last week that comes with inputs for a thermocouple and pair of relays capable of switching a hot plate or immersion heater. The osPID is based on the Arduino and was created by [Brett Beauregard], author of the Arduino PID library.

Getting to the meat and potatoes of the build, [Phil] connected a 300 Watt immersion heater to the osPID and put the heater in a bowl of water. A delicious looking cut of beef tenderloin was shoved into a ziplock bag and suspended in the bowl of warm water for a few hours. With the heater and thermocouple attached to the osPID, the temperature was set at 130° F and the entire device was left alone for a few hours. Looking at [Phil]‘s recipe for tenderloin with lemon parsley butter whets our taste buds, so we’ll hope [Phil]‘s dinner came out just fine.

Kitchen Hacks: Sous Vide builds don’t need to cost an arm and a leg

It’s not that we haven’t seen inexpensive Sous Vide builds. It’s just that we enjoy the fact that [Kelvin's] Sous Vide machine gives new life to unused things. The cooking vessel is a crock pot which he acquired for just $3. He housed it in a large Styrofoam box which he got for free through his local freecycle program. The circulation pump is a $0.99 fish tank part that pushes about ten gallons per hour.

He even hunted around to find the best prices on the control circuitry. The PID controller is obviously the most important part, as it will regulate the cooking temperature. He found a greatly discounted module that set him back just over $30. It even has a self-learning feature that sounds like it’s handy (not sure if all of these have that though).

Check out the video after the break. We like the use of his old RAM heat sinks to help dissipate heat from the solid state relay that drives the heating element. Since that SSR is inside of the foam box we could see heat becoming an issue. This way it’s dissipated, but not wasted.

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Sous vide with racing stripes

We’re not going to question the logic that went into putting racing stripes on a slow cooker, but [Evan]‘s sous vide machine is the most professional one we’ve seen.

After [Evan] found a cooking book that went into the physics and chemistry of making a meal, he wanted to make some really good meals. Sous vide spoke out to him and [Evan] committed himself to building an immersion cooker.

After trolling around on the Internet, [Evan] came across a little gem on Make. The Make build was cheap – it was built around an off-the-shelf PID controller and thermocouples. [Evan] though about building his own PID controller, but time is money and he couldn’t beat the commercial version in features.

The enclosure was the most time-consuming part of [Evan]‘s build. It’s a 1/8″ sheet of aluminum cut and bent to the correct size. The sharp edges were filed down and joined with epoxy; definitely not the ‘normal’ way of building an enclosure. The color scheme is borrowed from this Renault – French cooking inspired by a French car.

As for [Evan]‘s results, he cooked a 5oz filet marinated in garlic, thyme, olive oil, salt and pepper. This dish was flanked with some roasted Yukon Gold potatoes and sautéed broccoli. Our mouth is watering just looking at the picture, so we’re betting [Evan] did an excellent job.

Kitchen hacks: What would you cook if you had a Sous-Vide this large?

We’ve seen no shortage of temperature controlled immersion cooking devices, called Sous-Vide, around here. But this one probably has the capacity of all of them combined! Flickr user [RogueGormet] isn’t writing about the build, but his Large Form Water Oven build photo set speaks for itself.

We’d wager that the donor vessel is a 16-gallon chest cooler. He cut the lid into two sections, sealing off the insulated cavity with High Density Polyethylene (the stuff those white cutting boards are made out of). This gives him a place to mount the heating element, with a box for the PID controller riding on top. A submersible pump keeps the liquid moving to help regulate the cooking temperature throughout.

What do you put in one of these? Right off the top of our heads we’d think he had something like a pig roast planned. But it could just as easily be a Turkey, or other large hunk of meat. What would you use it for?

If you don’t need quite as much capacity you might make some alterations to your slow cooker for your own immersion cooking.