robertdi8 wrote: I just checked my flow-rate: 562.5 ml/min!!!!!! I can't remember my previous rate as I have not had any problems previously. I wonder if the welding tip clearner reamed out some of the 0.6mm diameter leaving me with a slightly larger modified gicleur now. Time for coffee to really test it out.

Dave.

Although ruby rates a 9 and diamond a 10 on the "Moh's hardness scale," the scale is not linear and a diamond is supposedly around 5x as hard as a ruby.

I have no doubt that you have reamed out the hole in the ruby, somewhat. A flow rate of 560+ ml/minute is the highest I've heard of with the standard 0.6mm orifice (typically, one gets from about 400 to 480ml/min with the 0.6mm gicleur unclogged. I'd say that 450ml is "usual").

I still get around 800ml/minute with my custom 0.8mm gicleur. I have not noticed any difference in shotmaking parameters, at all, with the sorts of doses that I use, e.g. around 14g. With higher doses there conceivably could be some impact due to the loss of some preinfusion, although I have no personal experience with that on this machine.

ken

Interestingly I have noticed a change in the action of the machine since I unclogged my gicleur.

I do use "pre-infusion" and at the end of said infusion I now get some flow of espresso. This never happened previously. Occasionally with a grind change I would get some "basket sweat", but never actual drips. I figure there must be an increase in the volume of water applied during the pre-infusion with my "reamed" gicleur.

As well the ramp-up is considerably slower, perhaps mimicking the action of an E-61. For this I cannot figure out an explanation??? Any ideas......

With these changes I have yet to produce the quality of shot I had previously dialed in....I suspect I will eventually figure it out.....I hope

Dave.

robertdi8 wrote:I do use "pre-infusion" and at the end of said infusion I now get some flow of espresso. This never happened previously. Occasionally with a grind change I would get some "basket sweat", but never actual drips. I figure there must be an increase in the volume of water applied during the pre-infusion with my "reamed" gicleur.

This should be expected; you will need to cut back your preinfusion timings to account for it I think, as I rather feel that with the GS3's preinfusion you want to avoid letting it fully pressurize the puck in the preinfusion phase. It just seems like a bad idea to me though; I haven't messed with it firsthand. Anyway, again this makes perfect sense. Higher flow rate means that it fills the space above the puck quicker and starts pushing through it with gusto sooner.

As well the ramp-up is considerably slower, perhaps mimicking the action of an E-61. For this I cannot figure out an explanation??? Any ideas......

What do you mean by "ramp-up?" Are you talking about when the gauge hits max pressure, when you hear the chamber fill up, or something else? This doesn't make sense to me and seems to be counter to what you just described above; I fear I may have misunderstood you.

robertdi8 wrote:Interestingly I have noticed a change in the action of the machine since I unclogged my gicleur.

I do use "pre-infusion" and at the end of said infusion I now get some flow of espresso. This never happened previously. Occasionally with a grind change I would get some "basket sweat", but never actual drips. I figure there must be an increase in the volume of water applied during the pre-infusion with my "reamed" gicleur.

As well the ramp-up is considerably slower, perhaps mimicking the action of an E-61. For this I cannot figure out an explanation??? Any ideas......

With these changes I have yet to produce the quality of shot I had previously dialed in....I suspect I will eventually figure it out.....I hope

Dave.

The programmable "preinfusion" on the GS/3 is not really pre-infusion at all. Most people whose posts I've read have indicated that this setting is either totally useless or maybe useless for doubles but marginally useful for singles. This is not what I was referring to in my post, the "preinfusion" that you can program in on the GS/3's menu.

Going from stock, from about 450ml/min of flow, to what I have now, around 800ml/minute, might produce some sort of observable difference in shot production. I have not noticed it, but I am open to the idea that an observable change might be there.

With the sort of difference you are reporting to us, from ~450ml/minute flow to ~560ml/min, I am very skeptical that continued testing would reveal any difference that would not be camouflaged by the obvious variation from shot to shot, based upon all the other factors that determine shot quality, to list but a few, the grind, the dose, the basket preparation and tamp, etc. etc. etc.

ken

It's almost a 25% increase in flow rate; that's not trivial. I suspect you nailed it before when you guessed the effect of such changes is probably dependant on dosing style (I would add, overall shot prep style). I would guess that the heavier you dose and the coarser you grind, the more you'll see the water debit change your shots' overall flow characteristics. I sure noticed changes when I was playing musical gicleurs on my setup, though I'm hesitant to apply my experience here given my very different pump setup.

shadowfax wrote:It's almost a 25% increase in flow rate; that's not trivial. I suspect you nailed it before when you guessed the effect of such changes is probably dependant on dosing style (I would add, overall shot prep style). I would guess that the heavier you dose and the coarser you grind, the more you'll see the water debit change your shots' overall flow characteristics. I sure noticed changes when I was playing musical gicleurs on my setup, though I'm hesitant to apply my experience here given my very different pump setup.

Hi Nicholas,

My view is that all of this stuff is more complicated than it seems. That 25% increase in flow rate is only present in a system with no resistance to flow. Once you put the coffee into the PF, everything changes! Preinfusion (the real type, not the programmable type on the GS/3 setup menu) is important when updosing, and much less so when using more moderate doses, in the range of 14g, as I use. There is something about the particle size distribution in a smallish, ~14g, dose that seems (to me) to be more adaptable to differences in pressure ramp up, than when using a larger dose ground appropriately for that dose, more nearly filling the portafilter.

We don't know enough about how Dave is dosing or grinding his coffee to go very far beyond this point in the analysis.

What I can say from my own experience is that (forgetting for the moment the "programmable Preinfusion on the GS/3") is that relatively minor changes in grind settings determine when I will see the first few drops of an extraction exiting the bottomless PFs in my machine. I doubt sincerely that the programmable PI in this machine changes very much. So to say that the first drops appear after XXX seconds now but it took xxxxx seconds before, well to me that is more or less meaningless. All it would take in my situation to get that sort of observable effect, would be to have a storm system pass through town, changing the ambient humidity, or having my coffee age a few more days. Titan level grinders are GREAT, but owning one or more of them does not mean that you won't EVER have to adjust the grind setting in response to changes in the environment or in the coffee itself!

ken

Well, I took a little time before I re-posted to observe how my shots poured across: time, different coffees of variable freshness, grinder settings and baskets (doubles and triples). I guess, I have to agree that my initial findings were likely due to the usual variables of coffee, dose, grind etc.

However, I do continue to notice a change in the action of the automated "pre-infusion" (whether it is helpful for shot preparation is another question completely). It still seems to force a greater volume through the puck in a shorter period of time when compared to my pre-ream shots. Perhaps the "pre-infusion" routine is not able to adjust for the larger diameter gicleur. I imagine the algorithms for the "pre-infusion" could be simpler than the brewing code.

Regardless, I suspect that any difference in my shot characteristics relating to the change in gicleur are probably beyond my palate to discern.

Now on to my new boiler leak!!!!!
Dave.

(to Ken)

I just had my gicleur upgraded to the .8mm at the LM office in Ballard, my flow is 610ml per min. As you mentioned, pulling good shots when updosing is a challenge (17-18g)...channeling, very sensitive to pressure ramp, etc.

Net-net, my shots have been sub par after changing to the larger gicleur.

I wanted to follow your approach of 14g dosing...wondering if you use the LM dbl ridged basket? Also, if you are using a LM dbl ridged basket, what size tamper do you use (so you don't bottom-out on the ridge?)

Any other re-produceable parameters that you follow..?

Cheers, Jason

cant you just change the "program" for the pre-infusion?

make it be on for a shorter time then wait a bit longer before turning on again?

does that make sense?

jon

jsutton wrote:(to Ken)

I just had my gicleur upgraded to the .8mm at the LM office in Ballard, my flow is 610ml per min. As you mentioned, pulling good shots when updosing is a challenge (17-18g)...channeling, very sensitive to pressure ramp, etc.

Net-net, my shots have been sub par after changing to the larger gicleur.

I wanted to follow your approach of 14g dosing...wondering if you use the LM dbl ridged basket? Also, if you are using a LM dbl ridged basket, what size tamper do you use (so you don't bottom-out on the ridge?)

Any other re-produceable parameters that you follow..?

Cheers, Jason

Hi Jason,

I"m just back from a very long day spent in Boise (garden spot of Idaho ) after long 160mile drives in each direction with a friend who broke his leg skiing with me 3 weeks ago. But I digress . . . . .

As to how I get the actual dose, I use a 0.1g scale, weigh each dose, which I discharge into a ramekin from the doser of one of my grinders. I'll generally use anything within a couple of tenths of a gram either way, unless I am intentionally updosing for some other reason such as I wanted to updose or I forgot to change the grind after a shot that flowed too fast, or I screwed up in some other way.

I am currently using some baskets I got from Michael and Angelo of Espresso Resource in LA (1-818-786-7179) which I forget the name of but they have smaller and more precise holes drilled then your typical double basket, in a bottomless PF. It is ridged and works best with a 57mm tamper.

ken