doublehelix wrote:Looks very cool! And BIG-- very big....

The Daily Coffee News article calls out 43 cm tall, 16.9 inches. The Behmor BraZen is listed at 15.25" high, but the Spinn looks much taller from the picture in the article. The width of the Spinn is stated as 18 cm (7") wide and the BraZen is 9" wide.

poison wrote:The floor of the centrifuge already moves, for puck ejection purposes. but it's not the depth of the centrifuge that will have the effect, because the grounds will be compacted as it spinn, with the walls of the vcentrifuge becoming the floor as it rotates. Dose size will affect depth automatically.

Okay-- what I imagined, but could be wrong, is that the Spinn basket is like a washing machine--the cylindrical basket spins and the grounds get pressed up along the basket walls. Assuming even wall coating with grounds, the depth and diameter of the spinning basket will modulate the effective "puck" thickness for a given dose of grounds. I guess "tamping" and distribution can be accomplished by a pre-spin (slow, then fast), prior to adding hot water.

Interesting to see how damp/dry ground distribution along the wall work as a way to maybe pre-infuse.

The floor here, is the bottom of the basket?...neat that it will automatically eject.....

I did some math, under assumption it will work on similar principle like washing machine or that Bosch coffee machine.
It seems to me that it's not possible to get tamping force and brewing pressure in espresso range at 8000 rpm
Also, I'm not sure about the way of cleaning remains of extracted coffee in the machine

My bet - if it was possible to get results comparable to espresso this way, someone would already have made it.
But let's hope I'm wrong

How can you do math, if you don't know the diameter/dimensions? These guys own the patent on it, no one else CAN make it.

The floor of the centrifuge raises and pushes the compacted coffee off the walls of the centrifuge. I assume a quick spin dumps them off the edges into the basket below.

I've read the patent material, it's fascinating. It most certainly can exert much higher than 9 bar. The effect of the extracted coffee being flung at high speed against the outside walls of the centrifuge causes emulsification of oils, and causes a much denser, creamier crema. Cool stuff.

I made an estimation of diameter about 10 cm

Can you post a link to that patent material ?

I think it's between 4-5in diameter.

I like using nomograms for thinking about RCF (relative centrifugal force); the effective force on the coffee/water mixture scales as RPM^2. Doubling the RPMs quadruples the effective force; the effective force is linear with radius:

http://clinfield.com/wp-content/uploads ... mogram.gif

Well that's handy. What's the g>bar translation?

They are not really directly translatable....need to figure the actual force. My own quick arithmetic here, using the mass of water per sq inch, I think reckons with vit's estimations. I get something like 3 Bar; meaning I think their effective pressure could be within traditional espresso range of ~9 Bar. Caveats: my estimations may be off by a factor of 10, and my arithmetic could be suspect.

Yeah, I also got around 3 bar at the inner surface of the coffee layer, assuming 10 cm diameter of the drum and 8000 rpm, but this depends on the thickness of the water layer above the coffee layer and how it is dosed into the drum. But pressure drop through the coffee layer will be lower than in traditional espresso, due to centrifugal force. Pressure will gradually fall to zero towards the end of extraction, unless you leave extra water in the drum

I don't know how "tamping" is performed - if it is by centrifugal force only (and not some mechanical device), I get, according to similar calculation, about 1.5 kg at the outer and 0 at the inner surface of the coffee layer

Compared to traditional espresso, it seems to me that outer layer of the coffee will be more extracted, and inner layer less. Hard to say what it means in the terms of quality, but not sure it is for the better

These values increase by enlarging the drum diameter, but problem is - thickness of the coffee layer decreases

Of course, these are estimations - we engineers are used to do those things and of course, we are sometimes wrong