SousVide Dash Frequently Asked Questions (FAQ)
Q: What is this all about?
A: Sous vide is a cooking technique in which food is sealed under pressure, usually in plastic bags, and then cooked slowly in rapidly circulating water held at a precise temperature. SousVide Dash is an interactive dashboard designed to help determine the optimal sous-vide cooking time for a variety of foods. By simply choosing a food, shape and dimensions, one can get an estimate of how long it will take for the food to reach temperature and how it will get there. For more details, see our About SousVide Dash page.
Q: Can the app use Fahrenheit or does it only support Celsius?
A: Yes. As of version 1.1 both °C and °F are supported. To change, got to the Settings app; it's the grey gear icon on the main screen of your iPhone/iPad/iPod touch. From there, scroll down to Apps, and look for SousVide Dash along with your other apps. Select it, and you can then change the temperature unit setting. If you don't see the setting there, you are still running version 1.0 of SousVide dash. You can upgrade to the latest version here.
Q: Can the app use inches or does it only support millimeters?
A: Yes. As of 1.1 both millimeter and inches are supported. You can change your preference in the Settings app just like you can change temperature units. See the previous question for details.
Q: On my iPhone/iPod Touch I see some of the parameters of the simulation, but no graph or start button like on the iPad. Where are they?
Scroll down and you will see them. There is not enough room on the smaller screen to display everything at once.
Q: If I put the app in the background, will it still sound an alarm to let me know when the cooking time is over?
A: Yes, it will pop up a notification and beep with the same sound it does when the app is running. If you ignore the notification, it will repeat every thirty seconds for five minutes.
Q: Hmmm, I'm not getting the notification described in the previous question when the app is not in the foreground. I'm running iOS 5. What should I do?
A: On the main screen of your device, click the Settings app (the gear icon). Select Notifications and then make sure notifications are enabled for SousVide Dash. If not, enable them and choose the style of notification you want. Make sure to enable sound also.
Q: My sous vide machine is not listed in the equipment menu. What should I do?
We are eagerly soliciting data from sous vide equipment manufacturers to expand the list of machines we support. If your machine is not currently listed, please tweet or email us about the equipment you are using. Please include contact info for the manufacturer if possible. We will do our best to get the parameters we need from the manufacturer and put them into the next version of the app.
In the mean time, please choose the equipment that most closely resembles yours. If you are not sure, the Custom (h=200) setting is a good place to start for professional-level equipment.
Q: Will there be Android, Windows Phone, Kindle, Mac OS X, and/or Windows versions of SousVide Dash?
Q: The app sometimes crashes when I toggle a setting. I'm running iOS 5. What should I do?
A: This is a bug in version 1.0 that as far as we know only affects iOS 5 devices. We have identified the problem and fixed it as of version 1.2. You can always upgrade to the latest version here.
Q: How can I see the geeky stuff, like what numbers you are using for thermal diffusivity, thermal conductivity, and heat transfer?
A: This information is located at the bottom of the main screen on the iPad, or two screens down on the iPhone or iPad Touch. Look for the heading, "Technical Details." If you want to change these values, turn on the Custom Physics control at the bottom of the setup pane.
Q: OK, I see the coefficients, but what do they mean and how do you use them in the app?
A: The coefficients are as follows:
- α — The thermal diffusivity of the food in m2/s.
- ρ — The thermal conductivity of the food in W/m-°C.
- β — The shape coefficient. This dimensionless constant corrects the simulation for the shape of the food.
- h — The surface heat transfer coefficient. This depends on the machine in use and how it circulates the water.
For a detailed discussion, see Douglas Baldwin's writeup.
In terms of the simulation itself, the app uses a 1-D discretization with shape coefficient (β) correction and solves the heat equation iteratively. Each iteration solves a tridiagonal system of linear equations with surface boundary conditions that depend on the constants above.