ohills Senior Member Joined: 14 Mar 2012 Posts: 14 Location: oceanside,ca Expertise: Just starting
Espresso: Rocket Giotto Evoluzione V2 Grinder: Vario
Posted Sat Sep 1, 2012, 3:01pm Subject: Rotary vs vibratory
I'm still trying to decide on a hx machine and have a question. All things being equal, is a rotary pump worth the added expense over a vibratory one. I'm really interested in the Rockets and like the added features of the evoluzione over the premium plus v2. I don't need the plumb option now but it might come in handy in the future.
Bgosselin Senior Member Joined: 26 Jul 2012 Posts: 51 Location: Canada,quebec Expertise: I love coffee
Posted Sat Sep 1, 2012, 5:56pm Subject: Re: Rotary vs vibratory
Noise?
Vib pump are usually louder. There is a video on youtube that show the noise difference between the rocket vib and rotary pump. It make a difference early in the morning. But if you grind your bean everyone in the house would be up anyway. :)
Posted Sat Sep 1, 2012, 7:24pm Subject: Re: Rotary vs vibratory
I picked the Rocket Evo over the Premium for the plumbable drip tray and the rotary pump. Being able to drain the drip tray is a bigger plus than you'd think.
Rotary and vibe pumps produce the same quality espresso. The rotary pump is quieter and is more durable than a vibe pump. Vibe pumps have a limited duty cycle to avoid overheating. With a rotary pump, you can backflush the machine without worrying about the pump's run time.
Posted Sat Sep 1, 2012, 8:10pm Subject: Re: Rotary vs vibratory
The E-61, plumbed, rotary, allows manual pre-infusion for the length of time you choose. If you do the plumbing it adds about 100-150 in parts if you use a softener and John Guest fittings. Mine is plumbed into a two gallon bottle, but it is still a relief to not have to fill the reservoir and not have to handle a filled drip tray.
Posted Sat Sep 1, 2012, 9:17pm Subject: Re: Rotary vs vibratory
I would vote for rotary pump. The noise is a lot more pleasant, and on an HX you will hear that noise often if you make more than one drink at a time.
Calculate the price difference as a percentage of the purchase cost of the vibe version. This will give you a better idea of how much more you're paying. After that you can consider how long you think you will have the machine. Imagine your choice is $1500 for a vibe or $2000 for a rotary. If you are kind of person who can keep a machine for 10 years, I would say that the %33 price premium is worth it. At 5 years you're paying $100 a year for the noise reduction, and I might be on the fence if I didn't really dislike the vibe noise. If you're the kind of person who changes machines more frequently, I would say that the price premium isn't worth it, and would recommend picking up the vibe version or a used rotary with a solid quality reputation for a bit less than the $1500 you would have paid for the new vibe (in this example).
As far as pluming goes, I think that having the option to go both ways is great if you can. You never know where life and upgraditus will take you, and a tank option might just help you hold on to the machine, or make it easier to sell if you have to.
EDIT: If you are in Oceanside CA, I would take a long look at the Astra GA that's on the BST right now and just a little bit south of you. I have a GAP and I love it. I like it more than the Cimbali Junior D/1 that I'm rebuilding. They are big (prosumer e-61s would sort of fit inside if that makes sense), but the performance is great, and the service can't be beat if you live within a car's ride of The Valley.
There are some people who say that a rotary pump machine produces a "purer" shot than a vibratory pump machine. I personally think it's hogwash. I'm sure some of the other more fanatical forum members would disagree with me. :-) :-)
It is clear that vibratory pump machines are cheaper than their rotary cousins, but they're also more compact, only because rotary pumps consume a lot more space. I wish I could say they're also cheaper to replace, but I don't know. I've noticed that in the reservoir versions of machines, they use a vibratory pump, but plumbed in machines consuming the same amount of space use a rotary pump.
You'll also notice in the video that the guy mentioned the number of shots per hour. Vibratory pumps have a lower duty cycle which is suitable for prosumer use, but not for commercial use. (I can't think of any commercial machine which uses a vibratory pump.)
As for their reliability, well, what comes to my mind are fish tank pumps, which are vibratory. Mind you, they pump air and not water, but I had one which ran for years and years and years.
Personally, if I lived in Europe, there is no way in heck I'd want a machine with a Vibratory pump, because I really can't stand the sound of 50 hz. A vibratory pump sounds so different at 60 hz, a bit more pleasant.
I believe that the difference in shots produced by a vibe machine and a rotary machine is negligible if the rampup-to-pressure times are equivalent. In other words, if the flow from the rotary is restricted (via gicleur or other means) to match the vibe pump, I don't think one can tell the difference in the resulting shots.
The rampup time from an UNrestricted rotary is very fast; this will force one to grind more coarsely and change the shot characteristics.
As Randy says, one of the advantages of a plumbed-in rotary is the ability to preinfuse at line pressure. This technique allows one to grind finer, and is extremely helpful in trying to coax sweet, balanced shots from lighter-roasted coffees.
Everyone remarks about the more pleasing sound produced by rotary pumps. What is not often said is that the annoying buzz emitted by vibe pumps eventually causes the user to go insane. This claim is easily verified by perusing the amateur forums.
Everyone remarks about the more pleasing sound produced by rotary pumps. What is not often said is that the annoying buzz emitted by vibe pumps eventually causes the user to go insane. This claim is easily verified by perusing the amateur forums.
This just isn't right. How can someone with such insight and knowledge reflecting years of experience describe himself thusly: "Expertise: Just starting"
;-)
"I don't suffer from insanity. I am enjoying every minute of it."
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