Is body of espresso on the DE1 thinner? - Page 10

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NelisB

Postby NelisB » Jun 12, 2019, 11:14 am

luca wrote: I'd point out that between the pump and the coffee, many vibe pump machines probably have a good deal of stretchy teflony/plasticky tubing and/or boilers that might contain compressible air, so I don't think it's enough to prove that there are pulses at the pump; for the theory even to hold weight, you'd have to make some argument that those pulses aren't negated by all of the intervening stuff such that they are an issue at the coffee.

How is this with the DE?

CwD

Postby CwD » Jun 12, 2019, 12:32 pm

Coming from a Strietman CT1, I can't say there's been any difference in the demands of puck prep when using similar profiles. The CT1 was still demanding if I slammed the gauge straight to 9bar and held it there. the DE1 is still forgiving if I do a preinfusion and profile the pressure. And vice versa, some of the DE's more direct profiles are very unforgiving and the CT1 is incredibly forgiving when I was using it normally with preinfusion or bloom and generally lower pressure. Which makes me think it is more profile related than column of water related.

I think Duvall's machine will be really interesting for testing some of these hypotheses. Piston driven instead of a pump, but repeatable profiling (or lack thereof), and straight stupidly high and low limits on flow. Just have to hope someone experiment-minded ends up with one.

truemagellen

Postby truemagellen » Jun 12, 2019, 1:27 pm

NelisB wrote:How is this with the DE?


Hopefully someone can answer this for you but I'll add the vibe pumps cause vibration in the entire case even when heavily insulated. So there was also the concern the vibratory pump causes vibrations in the puck and water through frame vibration. This lead to some people outboarding their vibe pumps and this increased the distance to the pump for the ultrasonic water concerns.

For comparison, rotary pumps are usually stainless steel braided rubber hoses with stainless compression fittings.

Does the DECENT pros or cafe models come with rotary pumps?

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NelisB

Postby NelisB » replying to truemagellen » Jun 12, 2019, 2:42 pm

The DE pump actually doesn't vibrate, it pulses! I would think this can have even more impact on the coffee

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rimblas

Postby rimblas » Jun 12, 2019, 4:41 pm

truemagellen wrote:Does the DECENT pros or cafe models come with rotary pumps?

No. And no hint that they will.

NelisB wrote:The DE pump actually doesn't vibrate, it pulses! I would think this can have even more impact on the coffee

Yes, two pumps pulse. One for cold water and one for hot water. Then it gets combined in a mixing manifold. Also, there was a lot of analysis done for the shape of the dispersion chambers in the grouphead to ensure the water flow was even when reaching the puck. And, also, the pumps are driven in a way that avoids vibration or resonance. They even skip cycles. Or in more technical terms, quoting from a post from the Decent Diaspora:

Technically it's a dithered single-bit sigma-delta modulator. You can't say anything about the output pattern. It's a noise-shaped pseudo-random driver. You shouldn't expect anything about the output.