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Thread: Going insane with channeling, pls help!

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    Going insane with channeling, pls help!

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I'm wondering whether someone might be able to diagnose this annoying channeling problem I've got. It's driving me crazy.


    I'm using a Unico Splendour machine with a convex 58mm tamper. FWIW I'm using Cosmorex Rio Gold beans which I grind at home using a Rocky doserless. I'm pretty sure the machine zeroes at 8 (out of 40) and I grind a 10, (but have also tried at 9). I weight 22g (sometimes 21g) into the portafilter and use the tamp to push the coffee down and it resides with normal pressure just under the raised 'lip'.

    BUT, I always get a channel hole at the same position, at 12 o'clock or 12:30 (see diagram). The consistency of the channeling occurring AND its position has to be something systematic. Any ideas? It's making great coffee taste not so great
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    Maybe try and drop the dose back a little and go finer. 22grams maybe just too much and there is plenty of info out there suggesting that over dosing can lead to channeling. Just a thought

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    Have you tried the nutating tamp technique (see post on this)? Helped reduce channeling for me.

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    Agreed, I've found that technique is great, especially noticeable with a naked handle

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    As it's always in the same position perhaps it's a machine issue, rather than technique. Maybe the screen is less clogged at that point?

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    My suggestion is that once you have done all your dosing and tamping etc, rotate the basket in the handle 90 degrees before you lock it in to the machine.

    That way you will be able to tell if it is you or the machine that is causing it to channel in that spot.

    If the channeling is still at the ~12:30, it could be something to do with the machine. Check the showerscreen for blockages, fouling, etc.
    If the channeling moves when you rotate the basket, then it's time to look at your dosing/tamping technique.

    Edit: Further to the above, when you lock the handle into the machine, try and take it out again before you make a shot and inspect the coffee to make sure it hasn't impacted the showerscreen before you brew. If the dose is too high and it hits the showerscreen before it even gets wet, this can lead to channeling too.
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    thanks all, these are all great ideas for me to try. I will do so and reply back when done.

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    ....can't change the entry point of the portafilter due to groves on grouphead

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    Turn the basket

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    ah so....!
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    Senior Member smokey's Avatar
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    I had the same problem when I started out with my silvia, after reading a whole lot of posts I worked out that I was putting just a touch too much coffee in the PF. When it gets wet it swells and hits the nut on the bottom of the shower screen where the hot water comes out, that causes the water to squirt out thru the crack. Looking at your pic I think it is similar to what I was getting.

    Instead of the stated 22 grams for my 22gm basket I use 21 grams, makes a BIG difference.

    Please let us know what works for you.

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    I used to have a channeling issue with lower doses until I was told to try and tamp harder. The problem stopped. Lower dosages require more resistance to the water flow and pressure, so this helped me a lot! Higher doses can be an issue too, the relativeness of the grind plays a major factor.

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    Are you sure it's channelling and not just a bit of grinds that sticks to the same place on the shower screen each time?

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    Perhaps you are just dosing more to the front of the basket? Try rotating the portafilter 90 when you fill it, and see what happens.

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    OK, an update on subsequent attempts.

    1. Used 21g + nutating method + coarser setting(10). This visually reset the coffee a good 2-3mm below the lip than when not using nutating method. Result: shot channeled in same position and pour was on the slow side. Interestingly I did get some oils on the periphery of the crema that I don't normally get. But in short it was undrinkable due to channeling.

    2. Used 20g + nutating method + coarser setting(10) + 180degree turn of the basket. Result: channel in same position!! pour was too fast, very watery taste and undrinkable.


    I will next try finer setting 9, but not sure of grams at this stage, maybe 21g as a start. Also need to dabble with a harder tamp as pnormal kindly supplied.
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    Senior Member NakiChap's Avatar
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    Have you popped the shower screen off to check if its clean, flip a tea spoon upside down a use it as a lever to pop off the shower screen from inside the group head.
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    I agree if you've rotated the basket, changed your dose and tamp, etc, and it's still channeling in the same spot at the top of the basket, it's sounding more like it could possibly be a machine issue.

    Have you locked the handle in place and then removed it immediately to check that the puck isn't being disturbed before you make the shot?

    If the coffee isn't being impacted, per above, check the shower screen and dispersion screen. There might possibly be fouling, scale, dirt, etc causing water to jet out harder in that area of the basket?
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    Senior Member GregWormald's Avatar
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    21 gms of "coarser" coffee sounds like it could be an overdose to me and the marks on your puck indicate this. As the water hits, the grounds swell and press against the shower screen causing the puck to crack.
    To check, after tamping, put a 5 cent coin on top of the puck and lock in. Remove and see if the coin is indented into the grounds. If it is, then an overdose is likely.
    As you are using a convex tamper, try this around the edge of the puck as well.

    Remember that changing the grind will change the *height* of the dose.

    Greg
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    I have to say, the extra "oil in the shot" is something I usually get from overdosing (or rather, choking the machine). They usually end up in the sink.

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    G'day "lucifuge"...

    I'd give the guys/gals at Cosmorex a ring and set up a training session with your kit and the coffee you are currently using. Just sounds like a technique issue to be honest, and with a bit of hands on training can probably be sorted out very quickly for you...

    Mal.

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    Quote Originally Posted by lucifuge View Post
    OK, an update on subsequent attempts.

    1. .... Interestingly I did get some oils on the periphery of the crema that I don't normally get. But in short it was undrinkable due to channeling.

    2 ... Also need to dabble with a harder tamp as pnormal kindly supplied. (earlier quote): using a convex 58mm tamper
    Two thoughts here.

    1) The only time I have managed to get oils like that in the shot, the grinder needed either a major clean, a complete recalibration (including shimming in the case of several friend's EM480's) or new burrs.

    2) If you do a level, careful, initial / pre tamp of the first 2 to 3 mm of coffee using a flat tamper w about 3 Kg pressure, it will "almost universally" minimise channeling. FWIW, some of the research on curved tampers indicated it was an attempt to correct problems in the dynamic flow of grounds within poor baskets. I concur. One other observation, the photo you provided shows a "ring" of grounds around the top. That often affects channelling.

    Having said that, I am not at all familiar w your machine. What happened when you rotated the basket 90 degrees?

    TampIt

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    Rotating the basket 180deg didn't change the position of the channeling; its still around 12'oclock.


    I did another attempt today; 20g + nutating + harder tamp pressure +finer grind. Had a minimal channeling spot, but still had ring indicating contact with the screen. But this coffee was best yet. Will try for 19g tomorrow!

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    I couldn't help but think a "nutating" tamp would create a worse distribution of grinds around the edge, this leading to a higher probability of side channelling. I'd go finer grind and lighter tamp.

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    jmc
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    Try this,
    Ignore supposed channelling issues as no-one can see inside the puck when making a coffee .

    Holes, divots,cracks etc are meaningless if basic technique is wrong.
    Ignore weights.

    Grind your coffee into the portafilter so that it is slightly overfull.
    Using the side of your finger as a scraper move the coffee around so that all holes are filled ( and the excess falls off )
    and you are left with a smooth surface level with the top of the basket.

    Do not push down.
    Do not tamp !!!

    Put the tamper on top and the weight of the tamper will compress the coffee slightly, then give it a twist. Do not push down.
    Make a coffee.
    If you haven't changed the grind, the shot will pull really fast. Discard the shot.

    Adjust the grinder finer and pull / discard shots until you can pull 30ml using the above method in 25 - 30 seconds.

    When you pull that shot do not release the portafilter until you have tasted the coffee.

    If the coffee tastes fine ( and if you have followed the above it will ) the problem is solved.

    It really doesn't matter what the puck looks like after the shot if the coffee tastes good.

    John

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    Something nobody seems to have mentioned - in your pic in the OP there is a ring around the edge where the grinds have been compressed. Look up into the group head and see what is causing that. It shouldn't be there. If you have something sitting in that groove it will affect the flow. Ideally the puck should not impact the shower screen enough to cause any indentation. The 5c test should leave an indent that is less than the thickness of the coin.

    Try removing the shower screen (and the 2nd screen if you have one) and clean them, then hold them up to the light. Look for blockages. When i got my machine I washed those parts, but still had blockages in them until I took a brush to them and scrubbed the holes clean.

    Check the filter the same way. My SB filters would regularly clog and took some scrubbing to clean all the holes - my VST one clean up far more easily.

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    Quote Originally Posted by lucifuge View Post
    Rotating the basket 180deg didn't change the position of the channeling; its still around 12'oclock.
    The ring-shaped mild indentation indicates slight overdose, but that deep indentation that still appears at 12 o'clock points to an issue with your shower screen. Stop playing with grind/dose for the time being and check your shower screen. Is there something stuck under the screen at 12 o'clock? If there isn't, remove the shower screen and check for clogging. If the screen is clogged except for the 12 o'clock spot, water could be exiting the group head faster at that spot causing channelling. If it's something that can be cleaned, clean it.
    Once that's sorted, start playing with grind/dose to finally eliminate the ring-shaped indent. BTW, you never mentioned what basket you're using (double or triple?). Is your basket actually rated to hold 20+ grams of coffee grounds?

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    OK, I got shower screen off and am cleaning it in the cleaning stuff. I noticed no issues on the screen or on grouphead, both were quite clean and un-impacted.
    Last edited by lucifuge; 19th November 2013 at 01:37 PM.

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    A video on removing and cleaning the e61 shower screen: Tech Tip: E61 Brew Head Maintenance - YouTube

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    Senior Member Yelta's Avatar
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    Quote Originally Posted by oble89 View Post
    A video on removing and cleaning the e61 shower screen: Tech Tip: E61 Brew Head Maintenance - YouTube
    Crikey, wouldn't let her within a country mile of my machine, what a clumsy removal of an E61 shower screen, all of that poking and jabbing with a screwdriver all it takes is the end of a teaspoon inserted where the PF bayonet lugs slot in, then lever on the bottom lip of the screen, first one side then the other, all up 5 seconds at the outside.
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    Senior Member chokkidog's Avatar
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    But Yelta, those girls are the world's greatest experts on coffee machines!!
    You know, like, they're on You Tube....................!!

    ;-D :-D ;-D

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    Yeah.. that's not the most graceful manner of removing the shower screen, but it can at least give the OP an idea. The lady's silliness of choosing a hot machine to do the demonstration wasn't exactly brilliant either
    I watched the video long ago, but did it much more gently myself with a spread knife when the time came to remove the shower screen (more leverage than the back of my teaspoon without the sharp, dirty edge of a screwdriver). Hopefully OP gets the idea and it helps him remove and inspect his shower screen without being as clumsy as the lady in the video cuz I couldn't find a better video in short notice :P

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    Quote Originally Posted by chokkidog View Post
    But Yelta, those girls are the world's greatest experts on coffee machines!!
    You know, like, they're on You Tube....................!!

    ;-D :-D ;-D
    Sorry Chokkidog, my mistake.

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    OK, an update...

    I am now using a Pullman Tamper with a matching 18g VST basket. I've probably pulled 20 shots since, (most for calibration) and not once was there any channeling at all!

    Today I gave my Rocky Rancilio Doserless a huge cleanout. Interestingly, the coffee coming out is clumping somewhat, but at 8 years+ or so old, that's not unreasonable. I'm probably due for a new grinder and really want a stepless one this time. Any suggestions, pls go ahead it would really help. I have my eye on a Eureka Mignon but that's it at the moment.

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    Channelling has gone completely away for me with:

    1. Correct dose, most important. Over-dosing will destroy the top of your puck and lead to channelling almost every time.
    2. Well settled coffee (similar to a WST or something, but just using lots of light tapping and sweeping to fill in the gaps).
    3. A very light "nutating" tamp before the final tamp.

    This has lead to only very small variations in my shot, so much so I am more than happy to use the programmable volume in the machine.

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    Quote Originally Posted by lucifuge View Post
    OK, an update...

    I am now using a Pullman Tamper with a matching 18g VST basket. I've probably pulled 20 shots since, (most for calibration) and not once was there any channeling at all!

    Today I gave my Rocky Rancilio Doserless a huge cleanout. Interestingly, the coffee coming out is clumping somewhat, but at 8 years+ or so old, that's not unreasonable. I'm probably due for a new grinder and really want a stepless one this time.
    Hi Lucifuge

    There are a few posts about Rocky's not really being up to the job for VST baskets. My experience of one friends Rocky was strange at the time: far better coffee out of one of my EM480's when we used his VST / naked. Turns out (much later info) that VST's do not like the lower end market in flat burr grinders (too many fines, too inconsistent a range of particle sizes). The EM480 is a low end conical and is a lot better for the VSTs.

    If you go naked, your current setup may make it a move backwards. Later, it would be a good thing to experiment with.

    I now also have a Mahlkonig Vario ceramic flat burr grinder (aka Baratza in the US, Mahlkonig actually make them). For home use it beats the stepless at their own game: 10 "macro grind settings" of which 1 to 3 is espresso grinding range. A to W "micro grind setting" within each step. Result: dials in faster than any other grinder (esp. stepless) I have ever used. The other good news: Its quiet, small, doserless, accurate time setup with virtually zero grind retention. The bad news: the idiots did not put a on / off sensor switch where the portafilter is inserted & the p/f holder is a poor design (esp. for a naked); so you need two hands to use it - one for the p/f and one for the switch. As usual the best grinder is still out there somewhere. For espresso, the Vario is probably the best one for "serious CS home use". Just under $700.

    Hope this helps


    TampIt

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    The EM04x0 do what they're meant to do, grind small amounts of coffee for home use. They're obviously not on par with larger commercial-use derivatives with dosing chambers and much larger burrs. But the machines are fairly reliable, predicatble and easy to maintain. I'll be keen on reviews of the EM0700 but I am pretty happy with the EM0480 now.

    Clumping is largely to do with moisture in the air more than anything, and maybe moisture in the beans.

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    Quote Originally Posted by TampIt View Post
    Hi Lucifuge

    There are a few posts about Rocky's not really being up to the job for VST baskets. My experience of one friends Rocky was strange at the time: far better coffee out of one of my EM480's when we used his VST / naked. Turns out (much later info) that VST's do not like the lower end market in flat burr grinders (too many fines, too inconsistent a range of particle sizes).


    Hope this helps


    TampIt
    I love my Rancilio Rocky it is an excellent grinder that produces excellent coffee.

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    TOK
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    Quote Originally Posted by TampIt View Post
    Hi Lucifuge

    There are a few posts about Rocky's not really being up to the job for VST baskets. My experience of one friends Rocky was strange at the time: far better coffee out of one of my EM480's when we used his VST / naked. Turns out (much later info) that VST's do not like the lower end market in flat burr grinders (too many fines, too inconsistent a range of particle sizes). The EM480 is a low end conical and is a lot better for the VSTs............
    Ah yeah and playing devil's advocate, another interpretation of that could be that the vst is not fit for purpose if it wont work with well established espresso making gear.... use a rocky with regular commercial filters and you get a perfectly good cup of coffee (usual caveat that you have to know what you are doing, but that's the same with everything). So we could reverse the comment to say vst is not up to the job.....which is cheaper / easier to replace, a filter basket or a grinder? And in view of the thread as a whole....if best practice is used to make the coffee and the result is already really good, what does it actually mean if you spot a channel in your puk?
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    Senior Member Yelta's Avatar
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    Quote Originally Posted by TOK View Post
    Ah yeah and playing devil's advocate, another interpretation of that could be that the vst is not fit for purpose if it wont work with well established espresso making gear.... use a rocky with regular commercial filters and you get a perfectly good cup of coffee (usual caveat that you have to know what you are doing, but that's the same with everything). So we could reverse the comment to say vst is not up to the job.....which is cheaper / easier to replace, a filter basket or a grinder? And in view of the thread as a whole....if best practice is used to make the coffee and the result is already really good, what does it actually mean if you spot a channel in your puk?
    I had a similar reaction when I read the remark about "Rocky's not really being up to the job for VST baskets" as far as I'm concerned just another chink in the VST armour.

    Most of us accept the fact that Rocky is an excellent little grinder, to claim its not compatible with VST baskets is laughable.

    From memory we are being told that VST baskets work best with a naked portafilter, and that we must use a nutating tamp or at least tamp progressively adding coffee to the basket a little at a time, and now Rocky simply ain't up to the task of grinding coffee for these thoroughbreds.

    Somehow the word finicky comes to mind.

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    TOK
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    actually it has been a new years resolution of mine all this year to steer well clear of mutating tampers
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    Quote Originally Posted by Yelta View Post
    I had a similar reaction when I read the remark about "Rocky's not really being up to the job for VST baskets" as far as I'm concerned just another chink in the VST armour.

    Most of us accept the fact that Rocky is an excellent little grinder, to claim its not compatible with VST baskets is laughable.

    From memory we are being told that VST baskets work best with a naked portafilter, and that we must use a nutating tamp or at least tamp progressively adding coffee to the basket a little at a time, and now Rocky simply ain't up to the task of grinding coffee for these thoroughbreds.

    Somehow the word finicky comes to mind.
    ....and in 19 days, Santa is gonna come down your chimney too...

    Another one for your mumbo jumbo thread Yelta

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    I've had no trouble with my VST from the get go.

    There's an old saying about a poor workman blaming his tools.
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    Quote Originally Posted by Yelta View Post
    I had a similar reaction when I read the remark about "Rocky's not really being up to the job for VST baskets" as far as I'm concerned just another chink in the VST armour.

    Most of us accept the fact that Rocky is an excellent little grinder, to claim its not compatible with VST baskets is laughable.

    From memory we are being told that VST baskets work best with a naked portafilter, and that we must use a nutating tamp or at least tamp progressively adding coffee to the basket a little at a time, and now Rocky simply ain't up to the task of grinding coffee for these thoroughbreds.

    Somehow the word finicky comes to mind.
    Hi Yelta

    VST's are a very high flow basket compared to any others I have seen. Not just my opinion: VST themselves and many others all say the same thing, as do measurements. Nakeds are not as restrictive in the coffee path as spouts (self evident). Unsurprisingly, VST's work a lot better in nakeds. The also have the heaven / hell of not hiding anything. 2g of stale coffee in a VST 15g double: sink it. A standard basket will mask the stale stuff to a much higher extent. Excessive fines: will not work as a VST will run bitter immediately.

    I agree the rocky is a excellent little grinder, my comment was that VST's do not like low end flat burr grinders (any make) because (mainly) of excessive fines. Simple. Easy to measure. Even a SJ has trouble with excessive fines when setting it up with a VST. VST's are at their best when the grind is just a little finer than the normal espresso range, whilst many good commercial grinders are not always at their best outside their designed espresso range (and that is fair enough in their case). Anything in need of a clean or with worn burrs: probably not good with a VST.

    Now the question: Does that make them finicky? Or revealing because of their precision?

    Any highly tuned thoroughbred / precision tool will only work at its best under the conditions it was designed for. ... and the last time you put diesel in your Ferrari?

    TampIt

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    I agree that VSTs allow both high and even flow. I don't agree that spouts add a significant level of flow restriction. If I did feel that spouts were flow restrictors would cause me to grind coarser when I use spouts (which I don't). As I've posted in another thread, I have grown to love my VSTs. TampIt, appreciate your posts on VST singles.
    Last edited by kwantfm; 7th December 2013 at 02:57 PM.

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    Quote Originally Posted by TampIt View Post
    VST's are a very high flow basket compared to any others I have seen. Not just my opinion: VST themselves and many others all say the same thing, as do measurements.
    Who is measuring basket "flow" ?
    What "measurements" are you referring to ?
    What has the "basket flow rate" got to do with brew pressure ?
    Water flows through all my baskets faster than the pump can deliver it... so the only restriction to flow ( and back pressure generator) must be the puck.
    OR .... .are you suggesting there is some previously undefined, yet important, relationship between the basket hole size and the grind size ?

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    The one thing that I can say with certainty is that, using an HG one grinder where I know dose weight to a high degree of accuracy and the grind quality is high, VST baskets demand a significantly finer grind than the stock baskets.
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    Quote Originally Posted by blend52 View Post
    Who is measuring basket "flow" ?
    What "measurements" are you referring to ?
    What has the "basket flow rate" got to do with brew pressure ?
    Water flows through all my baskets faster than the pump can deliver it... so the only restriction to flow ( and back pressure generator) must be the puck.
    OR .... .are you suggesting there is some previously undefined, yet important, relationship between the basket hole size and the grind size ?
    This page might help somewhat... How filter baskets affect espresso taste and barista technique - Reviews • Home-Barista.com

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    Quote Originally Posted by blend52 View Post
    Water flows through all my baskets faster than the pump can deliver it... so the only restriction to flow ( and back pressure generator) must be the puck.
    The puck sits against those holes. Not just sits against it, but forms a seal and pushes against it to deliver the flow of espresso. If there are more holes, there will be less resistance to what's coming out of the bottom of the puck.

    My VST and standard basket take the same dose (~18.5g) but require different grinds for the same flow rate because of the different holes configuration. The hole pattern and size absolutely make a difference and don't merely stop the coffee grounds from falling through.

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    Quote Originally Posted by Darkfalz View Post
    . If there are more holes, there will be less resistance to what's coming out of the bottom of the puck..
    Flow is proportional to total area. IE not just the number of holes, but their size also,
    So you could have a basket with 1000 tiny holes that actually flows less volume than one with 100 "big" holes.

    But if there are enough holes to handle the maximum flow the pump can offer, how would having more holes help ?
    OR.. as i said , are you thinking the grinds may effectively or partially "block" some of the holes ?
    IE , is there a important relationship between hole size and grind particle size ?

  50. #50
    Senior Member Yelta's Avatar
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    Behmor Brazen - $249 - Free Freight
    Quote Originally Posted by blend52 View Post
    is there a important relationship between hole size and grind particle size ?
    I would imagine so, if the holes were too large you would see fines in the bottom of the cup.



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