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The middle point: I can only comment on the tank version. Only used for backflushing, which Renzo starts by putting the teaspoon of chemical into the blind filter filled with water to the rim, inserting the portafilter into the group head, opening the valve to the middle position, and the chemical reaction causes a slooow ooze back up the open pipe and a slooow drip out of the base of the valve near the drip tray.
After a little while (allowing the chemical to dissolve the oils in the pipes), its followed up by eight true backflushes with the lever in the on position, held for a fast count to five, then off for a couple of seconds. On, then off etc. Then followed by one double-shot brew, which is tossed, of course.
I think Brett has it.
My understanding is that the half-stop allows the basic pressure of the system to begin the pre-infusion. If it is not plumbed in, there is no basic pressure, so that position opens a valve but nothing happens on a tank machine.
The built-in pre-infusion run by the pump is the essence of the E-61 design according to the patent.
Greg
On the Expobar, the middle position can also allow dribbles of water through.
For some reason, I had it in my head that the pre-infusion was for plumbed in machines only.
For non-plumbed machines, it doesnt do a proper pre-infusion as water pressure is a factor (but I may have dreamt it).
I normally use the middle position for backflushing. When I first get the caffetto into the system, I leave it in the middle position for a few minutes to allow it to soak.
Be careful using the "after half way before the pump" thingy on a tank machine, as it drains the HX and causes massive instability in temperature and also "burps" of air or steam into the brew water sometimes damaging the puck and causing channeling.
I think what Wrecker means is when its lifted just beyond the half way point (before it clicks the switch for the pump to activate) than water can flow.
You *could* also pull the lever up for a second, then release to half way, wait a second, then brew.
I have not noticed any advantages with these methods so I just let my E-61 do its own pre-infusion.
It has been discussed many times before and always seems to confuse people new to the E-61 world...
Originally posted by DavidR link=1215899466/0#8 date=1216208862
Originally posted by Intellidepth link=1215899466/0#0 date=1215899466
and telling me what the valve point on the lever was for.
So what is it for?
Its actually a passive pre-infusion point - as well as a handy gentle back flush tool / option.
The half way point on the lever allows a slight flow of water onto the coffee. This gentle flow of water wets the puck slightly which apparently helps with extraction and can also help eliminate channeling.
Its not necessary to use the position, as the machine pre infuses before ramping up the pressure anyway. But as a newbie getting routine, dose and tamp right I got myself into the habit of "if its got the function to help me, use it!" and I usually click into this position for a few seconds and then lift and start the shot. Wether it makes much of a difference I dont know, except to say that any fast shots Ive had have always been fixed by a grinder adjustment so I can only assume that it has been helping me.
Thanks for sharing the experience you had in our store. The pleasure was all ours, as we have witnessed your stepping into the "real coffee" zone with passion, admiration and anticipation for pulling at home the same shots quality demonstrated...this is our reward for sharing all we know with CSs , and empowering them to go on the next level of appreciation, we can get really emotional about it when it happens...
Happy its all working well for you at home!
For anyone who considers a VBM DS, we have now put a transparent cover around the machine, you can see the huge boiler, the commercial pressure switch and all other components were often raving about...
I ordered a Digital Thermometer from Jim its been made to fit in to where one of the existing bolts go above the group head and this helps to get consistant temps when trialing a new bean. Maybe worth having a think about?
The fact the VBM didnt move when you put the portafilter in - yep, one of the reasons it stood out for me too
Huge drip tray - yep, reason 2 and add ease of use of drip tray as well - just slides straight in and out
Looks the biz - I actually counted that as a plus, plenty of bling factor but somehow purely functional
Specs - yep, huge tank, huge boiler, 1800W heating power...
Sounds like we were on a similiar wavelength, all the way to a dosered stepless M4
...and I too was blown away by the quality and taste of the end product and now nearly a dozen visitors have too!
Wait until you start trying different coffees and different roasts you detect the subtle differences as well as the "expected" ones.
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