Hello, I am using a Brewtus 1 converted to a rotary pump offering manual preinfusion with the middle position of the E-61 lever. Although I really prefer to just start the pump and not use it, I know it can help my shots, but how much preinfusion is needed? Should I preinfuse until some coffee appears at the bottom of the basket? Or, is lesser amount, wetting the surface of the puck acceptable?
Also, when preinfuse starts it would first take some seconds to fill up the chamber of the E-61 head before water hitting the puck - is that correct?
I run about 20 lbs inlet pressure to the pump.
Thanks, Dennis

Nobody's used the middle postion preinfusion on an E61 since around 1961. You have the 8 to 10 second progressive infusion created by the cylinder in the brew head. This is the very thing everyone else is trying to emulate with line pressure preinfusion. Doing the middle leva position preinfusion on an E61 is redundant.

denniskeating wrote:Hello, I am using a Brewtus 1 converted to a rotary pump offering manual preinfusion with the middle position of the E-61 lever.

Greetings Dennis - is this because you adjusted the brew switch to achieve this?

Should I preinfuse until some coffee appears at the bottom of the basket?

That's the "instructions" in at least one lever machine operator's manual I read (Rancilio).

Also, when preinfuse starts it would first take some seconds to fill up the chamber of the E-61 head before water hitting the puck - is that correct?

No, both events are occuring simultaneously. I'm not too sure that 20 psi is sufficient but that would be easy to observe, i.e. can you take a nap or do you need to watch the basket?

Should you run any taste tests, be sure to stick to the same bean.

When I switched over to an external pump & motor and plumbed it in. The factory adjusted brew switch worked that way - allowing mains pressure to flow thru the head w/o the pump on. Actually, it will flow
out the shower screen as soon as I lift the lever to the mid position, so there is no delay to prefill the cylinder first.(simultaneous, as you noted)
I was under the belief that using this feature was better, and didn't realise the stock E-61 chamber did the job so well. I only run the mains input pressure at 20 lbs, because I am afraid of more pressure forcing it's way past my water solenoid and overfilling the steam boiler - then out the vacuum breaker on top to flood the kitchen. I probably should put a solenoid on the pump & motor, but that would eliminate the manual preinfuse feature.Abe Carmeli's machine is set up like that.
It took about 35 seconds to show any drops on the bottom of the basket. Yawn - that is why I never have liked to use this, and then only 10 seconds worth.
The reason I'm considering different techniques is my new versalab M3 grinder has distribution problems.
The coffee comes out the front half of the basket first. Even though I had a level machine, I releveled.
Yesterday, I took the portafilter out and rotated the basket 180 deg before loading it into the group.
That time, the coffee started out the backhalf of the basket. Gotta be the versalab!
I thought if I put more preinfusion into it, that may help, but it did not - I preinfused till drops showed on the basket and the pour still started out the first half of the basket. Thanks- Dennis

denniskeating wrote: The reason I'm considering different techniques is my new versalab M3 grinder has distribution problems. The coffee comes out the front half of the basket first.

It's not your grinder. This is a very common problem with E-61's. Water enters the E-61 brewing chamber from an inlet on its rear side. So, the water jets forward and tends to infuse the front of the puck first. When I had an E-61, I used to front-load the puck a bit to partially overcome this. You can also reduce the effect by installing a smaller gicleur (I did this, too).

Water flow in the typical E-61 grouphead is pretty even. The average flow in the passageway leading to the dispersion screw is truly snail's pace, especially under brew conditions. The dispersion screw has two drilled holes perpendicular to the thread axis and one central hole aimed directly at the "button" of the dispersion screen. As best I could measure (and remember long ago), the area of the two horizontal holes was equal to that of the central hole. Once water exists the dispersion screw and hits the button, we are at very low velocities. The effect is very similar to the water from your bathroom faucet hitting the slightly elevated drain stopper.

The holes in a typical basket are another story altogether. I don't have the data handy and, unfortunately, no pics but I would say that it is a good idea to soak your baskets in descaling solution every so often. Observing the basket holes (or lack thereof) through a high power stereo microscope was very revealing.

I just looked at my baskets thru the ceiling light, and saw two plugged holes, but that was all. I rinse and dry them right away after brewing a shot and have gotten out of the need to soak them like I used to. They looked pretty clear though.
Eric, thanks for your detail on the water distribution.
I enjoy the fast flow of my pump = 130 ml in 10 secs. I have a needle valve on the pumps output side, but usually leave it open. I can adjust the flow down to around 100 ml in 10 secs, then the valve is pretty limited. At either flow rate my brew pressure stays the same at 8.5 bars.
Can adjusting the needle valve accomplish the same results as installing a smaller gicleur?
Perhaps my pump is too frisky, and my extractions would benefit from less water debit.
I screed the coffee in four directions to fill up the center hole the m3 leaves, for uniformity, and tried overfilling the center and front area. Thanks, Dennis

Dennis - Assuming you can replicate this flow anomaly, take ONE of your baskets and soak it for an hour or so in descaling solution or simple white vinegar. It would be interesting to hear if the flow distribution improves with the "clean" basket. I can only say that viewing under the stereo microscope was quite revealing and showed visible evidence of calcification. Now I have no clue as to the effect all of this might have had and time does a good job of scrambling my memory.

I may need to lease you, for some outrageous sum, a gizmo for measuring the true pressure as seen by the puck.

Hello, Today I played with the pump needle valve adjustment and attached a p/f pressure gauge (flow controlled). Full flow 125 ml/10sec = 4 sec pump up to 8.5 brew pressure
Reduced 85 ml/10sec = 10 sec " " " " " "
Does this directly affect the length of time for preinfusion?
If so, I could benefit from a slower flow rate. I can still regulate it down to about 40 ml/10sec - that takes over 20 sec for the pump to pressure up.
Is my needle valve an adjustable gicluer? Thanks, Dennis

denniskeating wrote:Does this directly affect the length of time for preinfusion?

For sure, I would think so but you would be the best judge of that with the stopwatch "at the ready" and the bottomless PF in place.

Is my needle valve an adjustable gicluer?

Yes, sorta similar to the original E-61 patent which displayed an adjustable gicleur but I don't BELIEVE it was ever put into practice. IMO, your BEST BET would be to adjust your water pressure regulator on the inlet side of the pump to AROUND 35 psi and play with pre-infusion at the brew lever.

While reading all these high tech alternatives of preinfusing has its attractions, I would again like to remind everyone that any method that delays the first drop by around 5 to 10 seconds is fine. This makes shots more reliable and consistent in terms of preventing channeling.

However, there is absolutely no evidence that the length of preinfusion does anything else in pump machines, in particular, it has no bearing on the taste of a well made shot. So, if all this tech acumen is being harnessed because shots that are already preinfusing 5 to 8 seconds suck, it is a complete waste of time; the shots are sucking for some other reason. If on the other hand, it's just espresso-free tech talk, and nobody actually cares how the espresso tastes, carry on.

Hello, The reason I suspected my preinfusion was inadequate was the new M3 grinder. With my mini E and my pump running full flow, the shots were good, but the Versalab was wetting the front half of the puck first, and stayed that way thru the shot, overextracting that area. I thought it could be the fast flow, and using the mid lever position added preinfusion time - even till drops formed on the bottom of the basket.
That did not help, as even the preinfusion would show up at the front half of the basket first.
I plugged in the min E and pulled a couple of shots with good results.
I'm being careful to screed the dosed basket in four directions while filling up the hole it leaves in the center. The coffee is sprayed down in a circle with the center almost empty. Other M3 users seem to have good results distributing the grinds and tamping with the way the M3 puts it in the basket.
I even took my filled and tamped basket and rotated it 180 deg before locking it in - this produced wetting the back half of the basket first. If I WDT the grounds, or grind into something and then transfer the grounds to my basket, the problem goes away. I cannot seem to get a good shot working with the grinds as they are flung into the basket unless I rework the distribution entirely.
Ha-Ha -Jim, I know what you're thinking - throw the M3 against the wall!
Eric, thanks for the tip - I descaled my baskets yesterday - they are four years old .

One more question - Changing gicluers will affect the preinfusion time, but also affects,the thermosyphon flow too correct? My needle valve is at the output of the pump and should only affect flow rate? - Dennis

Changing gicleur size (from 0.70 mm to "x" mm) has no effect on the flow in the thermosyphon loop because the gicleur is not part of that loop to begin with.

denniskeating wrote: I even took my filled and tamped basket and rotated it 180 deg before locking it in - this produced wetting the back half of the basket first. If I WDT the grounds, or grind into something and then transfer the grounds to my basket, the problem goes away. I cannot seem to get a good shot working with the grinds as they are flung into the basket unless I rework the distribution entirely.
Ha-Ha -Jim, I know what you're thinking - throw the M3 against the wall!

Actually, I loved the way my M3 distributed; it was Versalab's excuse making and blame shifting for the transmission woes that gave me problems.

My guess is that either the lower brass funnel or the sweeper arm is misaligned. Try unscrewing it, correcting any obvious crookedness in the sweeper arm, and reassembling. If that doesn't work, try contacting Versalab, shrugging off your anger when they tell you how negligent you've been actually grinding coffee with it, and, after you've stopped laughing, applying whatever drop of glue or widget they send you to correct the problem

The alternative is to either remove the basket from the PF, and turn it 180 degrees halfway through grinding, or to rotate the PF handle gradually as far as it will go during grinding. This makes life easier on just about all doserless grinders

When I first got the Versalab, it was producing donut rings which I knew I'd have to work on. I took the bottom funnel & wiper off and the static wiper off to clean first time, but didn't touch any thing else.
Now it floods the front half of the basket , so that very well could be something I have screwed up.
I know my wiper is different now because it make a little noise spinning.
Question: Upon completion of grinding & removing the p/f there is always a rather large chunk of ground coffee that fall out last. It is about 3/8 to 1/2" size, and although not tightly compressed, is still one big chunk that falls into the basket. Is this normal?
It produced the chunk from day one - before I took it apart.
I will contact Versalab for advice - luckily I live 45 mi. from Versalab, so my grinder wasn't ever shipped - instead it rode home in a Lexus.
Thanks, Dennis

Sorry, but you probably did screw up when you fixed it -- it's supposed to fall like a donut into the basket, that makes the leveling a complete breeze (since almost all channeling is along the basket rim). Mine used to lay a ground coffee egg of around 1/2 gram about 5 minutes after grinding; presumably when the static cling wore off. This was another good feature, since the coffee didn't end up in the next shot. This stuff is all in the original bench thread.

I've read all the threads since it's debut and re-read them over time, but that part escaped me.
I'm using their p/f holder,and more often than not the weight of my p/f handle drops a little which throw the symmetry off. It is about 1/8" lower in the front sometimes. That could contribute to the problem - maybe if I always hold up properly & level would help. Then I could twist to the left and to the right while grinding as you said.
I ground into the basket with my mini E and could rotate it by hand while grinding and then tap it down once. It didn't clump the grinds most of the time. I ended up with a basket ready to tamp and go that made good shots. - Dennis

The fluffy clump free grinds of the M3 is what always impressed me about the grinder. I was on the fence about one for some time but decided to go another route with my grinders. I did do some playing with pre and full infusion. I consider preinfusion to be filling the head-space with water and partially saturating the puck before the pump kicks in. Infusion was completely saturating the puck but no drops from the bottom of the basket before the pump kicked in. In my case I was using an old two group rotary that had no preinfusion at all, as most solenoid controlled rotary pump driven machines. On this particular machine a full infusion evened out my extractions and improved the shots. I used an adjustable delay-on-make timer so I could allow the puck to fully saturate before the pump kicked in. I believe that was around 8 seconds with my 3 bar mains pressure. On the rotary pump lever actuated machine I had no need for it since it has natural preinfusion.

Unlike your case, even if I dosed half a basket, rotated it 180, or any other amount during dosing my shots always started at the front of the basket. The infusion minimized and/or eliminated that problem. Since you are using the lever based E61 you probably dont need any kind of additional preinfusion. The fact that if you rotate your basket before you lock it in, and the over extraction portion moves from the front to side/back would definitely point the finger at either a bad distribution, of an off center tamp. As Jim points out, it sounds like you may have inadvertently modified the grinder from the way it was suppose to work, that being the fluffy donut distribution. The slightly off center portafilter could be contributing to the issue because of the light and fluffy grind of the M3 but it seams rather extreme for such a minor offense.

I get a good round donut distribution from the M3, extremely fluffy. Very nice. Aparrantly Jim also had a coffee nugget which dropped out the bottom afterwards. I guess I try to use my nugget with the other grinds in the basket. I weigh the dose before grinding now and try not to lose any coffee.
As for my machine, I turned my valve down so flow is 85 ml/10sec. That takes about 10 secs for the pump to pressure up for the preinfusion. That should work out nicely. Dennis

I've got a PID'ed silvia in the mail and I'm excited for it to get here! It's only a slight upgrade from my Gaggia, but I'm excited nonetheless. But all this preinfusion talk has got me somewhat jealous I must admit...

Has anyone experimented with a sort of manual preinfusion, along the lines of this:
-Remove portafilter
-Dose, Level, Distribute, etc
-Tamp
-*Place portafilter directly under group
-*Run pump for a few seconds, soaking the puck evenly with the spray from the shower screen
-Pump off
-Lock and Load and Brew!

I really have not had the chance to play with a machine with preinfusion, but would it be possible that this sort of method could achieve similar results?

Sincerely,
Bill