Start spinning more food in your kitchen than just salad. Bring the danger of the workshop into the kitchen with a homemade centrifuge! By using an electric circular saw as the motor, I was able to spin food up to 1800 G's and achieve separation in liquids, all for under $20. This small capacity centrifuge gives a taste of what a centrifuge can do for your kitchen.
*Do not replicate this project, it is incredibly dangerous!!
How centrifuges work:
A centrifuge is a rotational platform around a fixed axis. Using the sedimentation principle the centripetal force causes separation of substances with different densities in a liquid.
This rotational force is measured in G's, where G is the measurement of gravitational acceleration felt as weight. On earth we experience 1G, roller coasters experience anywhere from 2-5 G's, and many fighter pilots can achieve 9G's. Since the amount of G's is inversely proportional to the radius of the rotation, smaller radii can achieve some staggering G's. It's not uncommon for lab centrifuges to reach 10,000G's.
Why centrifuge food?
Great question. Those into molecular gastronomy and your average food nerd love when cuisine gets a modern, technical twist. By using centripetal force you can separate food into layers based on density. In a liquid, this means denser substances like pulp are forced to the bottom while lighter substances like oils float to the top.
This means you can separate pulp from juice that might take hours in a fine-mesh strainer, like carrots or peas. You can even clarify things like broths to make them crystal clear. There's no end to the amount of foods that can be spun and remixed.
This Instructable will walk you through my journey to centrifuge glory. I had success, and failure. I will show you both. Though I was successful with my experiment you would be better off buying an inexpensive one if you are interested in trying this out, both for safety reasons and larger volume.
Here's how I made my centrifuge (or centrifood).
What G's are achievable for this centrifuge?
Based on the variables for my built centrifuge [radius of rotational platform: 2.75" (7cm) and speed of motor: 4900 RPMs], this handy G-Force RPM Calculator works out my centrifuge to about 1879 G. I figure this number is optimistic, as this is not a precision machine. A conservative guess would put this circular saw centrifuge at around 1800G's.
Knowing that the 'slow' end of commercial centrifuges are around 1900G's I believe this is a acceptable entry to explore the lower thresholds of what a centrifuge can accomplish.
With this much power there is a real danger of failure, and the failure will be catastrophic. Considering that even professional centrifuges fail, making your own centrifuge is extremely dangerous. Here's some photos to show what lab centrifuge failures look like: Cornell, Perdue, and MIT.
I provided my failure pictures in Step 10 and Step 14