The E61 group is often touted as featuring pre-infusion since you can open the valve by lifting the brew lever without activating the pump. Is this supposed to work on all E61 machines?

I've seen suggestions that on double-boiler machines using reservoirs, only a dribble would show at the group during pre-infusion as water only has vapor pressure to push brew boiler water out into the group. Thus plumbing-in the machine seems to be the way to obtain pre-infusion with these.

So I just plumbed in my Profitec Pro 700, and lifting the brew lever, there is no water at all coming through the group; this was the same when using the reservoir. The machine works fine but I don't think it can make any sort of pre-infusion. Is this normal?

Not that I miss pre-infusion (can't compare with or without) but I just expected to see water running when lifting the lever. Perhaps the valve opens only when the brew lever is lifted higher and the pump is engaged?

on my E-61, I raise the lever about half way, and I get water flow without the pump, I have a plumbed in system.

I just watched Seattle Coffee Gears video last night on preinfusion where they discuss the E61. Sounds like the pressure from the plumbing should allow low pressure water to end the group. Also, on non-plumbed machines the residual pressure from the heated boiler should be allowed to enter the group when the lever is lifted up. So, sounds like yes, but I'm no expert at all though.

All E61 groups have automated preinfusion provided by the expansion chamber; Internals of an E61 Brew Head explains it in detail. Some E61 groups will open the brew chamber valve before engaging the pump. There's no clear consensus this "prewetting" capability is by design or oversight. *shrug*

So your saying your 700 won't pre-infuse on reservoir or plumbed in? Something is wrong then, E61s preinfuse either way but do work better from the water line pressure when plumbed in.

here's right from the 700 spec list:
Renowned for its contributions to maintaining temperature stability in professional grade espresso machines, the E61 is constantly heated with water from the thermosyphon system. The solid brass E61 also features a pre-infusion cylinder to wet your grounds with low pressure water prior to brewing to aid in the extraction process.

cmin wrote:The solid brass E61 also features a pre-infusion cylinder to wet your grounds with low pressure water prior to brewing to aid in the extraction process.

Not to put too fine a point on it, but that's referring to the expansion chamber whose operation is defined in the E61 patent, not "prewetting" under line pressure from water dribbling into the brew chamber prior to pump activation. Some E61 groups do that, most don't.

If you want to experiment with prewetting on an E61, adjust the pump activation plunger to delay the pump-on position until the brew arm is higher. Or just cut power and lift the lever up all the way, then power on to start the brew cycle. For what it's worth, I didn't find much benefit from prewetting... maybe reduced channeling? In my limited experimentation, I found too much prewetting/preinfusion would muddy the taste profile.

tkenny53 wrote:on my E-61, I raise the lever about half way, and I get water flow without the pump, I have a plumbed in system.

Ok, I definitely don't on my machine.

cmin wrote:So your saying your 700 won't pre-infuse on reservoir or plumbed in? Something is wrong then, E61s preinfuse either way but do work better from the water line pressure when plumbed in.

Well I'm not sure if it's "wrong" or not but one thing is certain: my Pro 700 won't let water through the group before the pump is turned on. I've seen a video (don't have the link at the moment) posted with someone doing a "3-sec pre-infusion" with the Pro 700, hence me scratching my head.

HB wrote:Not to put too fine a point on it, but that's referring to the expansion chamber whose operation is defined in the E61 patent, not "prewetting" under line pressure from water dribbling into the brew chamber prior to pump activation. Some E61 groups do that, most don't.

Oh, then it's kind of reassuring. However I really thought pre-infusion *was* pre-wetting the grounds.

However the quote on the the Pro 700 spec list specifically mentions wetting the grounds. That being said, I don't thing this "spec" is from Profitec so perhaps it was an extrapolation from the vendor -- that particular copy seems to come from WLL.

HB wrote: If you want to experiment with prewetting on an E61, adjust the pump activation plunger to delay the pump-on position until the brew arm is higher. Or just cut power and lift the lever up all the way, then power on to start the brew cycle. For what it's worth, I didn't find much benefit from prewetting... maybe reduced channeling? In my limited experimentation, I found too much prewetting/preinfusion would muddy the taste profile.

Those are great ideas, I'll try operating the lever with the power off tonight... but I think I already did during the plumbing process and nothing comes out. Anyway, thanks for the clarification.

Plumbed In
"Prewetting the grounds" with an E61 connected to the line is more than a dribble. As with all preinfusion which is not pump or lever assisted (i.e., not "pressure profiling"), preinfusion is at line pressure (typically around 3 bar), flow rate is determined by line pressure and diameter of the tubing; and the amount of preinfusion is a product of flow rate and time. It's not only preinfusion, but effective preinfusion.

Since line pressure preinfusion was not covered in Vanlente's patent; it's unlikely that it was a design goal.

In order to get line pressure preinfusion, the internal cam needs to be moved into a position so the outlet from the cam chamber to the group head is uncovered before the pump switches on. Some E61s come from the factory with the cam in the right position for line preinfusion, some don't. As far as I know the cam can be rotated on the shaft of any E61 to allow line preinfusion.

Reservoir Fed
E61 reservoir preinfusion, aka "passive preinfusion," is a small amount of water, for a short time, at a very low pressure, before pump pressure cuts in. As preinfusion goes, It's not much -- a dribble in fact -- but better than nothing.

Without the pump filling the preinfusion reservoir and floating the valve, water movement into the group is limited to a small portion of what's in the top reservoir, "powered" by gravity and thermosiphonic action. In other words, it might as well be nothing.

However, worth trying yourself. What do you have to lose?

Rich

I had a similar problem with my Duetto. when I had it on reservoir, I figured I just needed line pressure to get it to pre-infuse. Eventually, I plumbed it in, and there was still no pre-infusion. I contacted CCS and they told me to check the pump activation switch behing the brew lever. Sure enough, the dang thing was sticking out too far from the front of the machine case, so by the time I got to raise the lever high enough to open the innards and allow water to flow at line pressure, the switch was activating. I backed out the switch a little, until I could get a nice pre-infusion before the pump came on, and then tightened up the nut holding it in position. It's been great ever since. The brew switch on your Profitec is probably similarly constructed. Look carefull to see what the brew lever is in when the pump comes on. It should be about when it gets to the horizontal position. If it's coming on closer to 45 degrees, then you probably have the same issue I did.

Interesting. I'll take a look tonight for sure and come back with my observations.