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Thread: 15 gr VST confusion - odd results?

  1. #1
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    15 gr VST confusion - odd results?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi everyone.

    I am coming to the knowledge bank to help solve a bit of an issue.

    in short, I'm not getting the same quality of pours from a new 15gm vst as I do from my stock double basket.

    while the first couple of pours from the vst blew my mind, creamy, tasty goodness, I've struggled to get these since. There was some robusta in the blend I was using though. Now,while I get some Crema, using a differ blend/s, the creaminess is mostly gone and things are more watery.

    As an experiment I threw in the stock basket and immediately the coffee became unctious, creamy, good.

    While the answer seems obvious, ie use the stock basket, I'm keen to get this vst to hum again, as it did when I first used it.

    Does anyone have any experience using the 15gm basket, over say the 18 or 20?

    ive also noticed a few holes in my puck using the vst that don't happen on the stock basket. Wonder if this is part of the problem.

    ...advice appreciated!

  2. #2
    Senior Member flynnaus's Avatar
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    I think your answer lies in your last para: holes in the puck.Solution: work on the distribution.

    You initially had great results from your VST so now you need to work on consistency. You also mentioned using different blends so that would have an effect and you may need to adjust your grind. Stick with one blend for a while to help achieve that consistency.

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    Yeah, I thought those holes could be showing a distribution problem. Re changing blends, I make sure I dial in each new blend, however it wouldn't hurt to use the same blend for consistency. Mind you, I need to change the grind when moving between stock basket, which must be about 20 gr, and the 15 gr vst anyway.

    re distribution, I use a compak k3, and it seems to clump a lot, so I'm spending time trying to remove these - collapsing grinds, tapping pf pre tamp, wdt. Still not getting a decent distribution though.

    interestingly, not showing these signs of channeling when using the stock basket.

    on a side note, I also read a blog post from maxwell Colonna-Dashwood
    https://colonnaandsmalls.wordpress.c...0/15g-baskets/
    talking about only getting consistent results from the 15 gr VST when he lowered pressure to 6bar.

  4. #4
    Senior Member flynnaus's Avatar
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    Well some swear by the VST, others' experiences vary. I own a VST triple and no longer use it (I gave up on it). I find my stock Giotto basket delivers the desired results.

    Interesting article that mentioned some of the difficulties you have faced. Changing the brew pressure is a bit drastic as that can alter the brew temperature and steaming capability, though I say this without knowing what sort of espresso machine you have. Note that they are using a machine which allowed tweaking of brew profile and have access to various grinders.
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    Quote Originally Posted by tobeanornottobean View Post

    on a side note, I also read a blog post from maxwell Colonna-Dashwood
    https://colonnaandsmalls.wordpress.c...0/15g-baskets/
    talking about only getting consistent results from the 15 gr VST when he lowered pressure to 6bar.
    Not really relevant to you or the average home user. MCD use EK43 grinders along with much lighter roasted single origins.

    15g VST baskets are just finicky period, especially if one is dosing 15g = very shallow flat puck prone to cracking and channelling.
    As already mentioned, distribution is key, but over the years I found a big key to consistency with VST baskets is a custom fitting tamper. Otherwise stick to regular more forgiving baskets.

    Grind finer, into a paper cup, weigh the dose exaclty 15 to 16g, keep using that same dose and adjust grind until you find happiness.
    Easier to break up clumps in the cup with paper clip prior to dosing.

  6. #6
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    Quote Originally Posted by flynnaus View Post
    Well some swear by the VST, others' experiences vary. I own a VST triple and no longer use it (I gave up on it). I find my stock Giotto basket delivers the desired results.

    Interesting article that mentioned some of the difficulties you have faced. Changing the brew pressure is a bit drastic as that can alter the brew temperature and steaming capability, though I say this without knowing what sort of espresso machine you have. Note that they are using a machine which allowed tweaking of brew profile and have access to various grinders.
    an opera I don't have (I run a e61 style Hx). Won't be changing the pressure anytime soon. Particularly when it seems to make good coffee with the right baskets. Just sort of annoyed I need to use a 20gm double or nothing, or so it would seem.
    Last edited by tobeanornottobean; 16th January 2016 at 08:12 PM.

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    Quote Originally Posted by Steve82 View Post
    Not really relevant to you or the average home user. MCD use EK43 grinders along with much lighter roasted single origins.

    15g VST baskets are just finicky period, especially if one is dosing 15g = very shallow flat puck prone to cracking and channelling.
    As already mentioned, distribution is key, but over the years I found a big key to consistency with VST baskets is a custom fitting tamper. Otherwise stick to regular more forgiving baskets.

    Grind finer, into a paper cup, weigh the dose exaclty 15 to 16g, keep using that same dose and adjust grind until you find happiness.
    Easier to break up clumps in the cup with paper clip prior to dosing.
    yeah, bought my vst with a custom Pullman tamper so no issue with fit. I grind into a cup so I can weigh (15g) and empty into a jam funnel. Also played with 16 g but that's not helping.

    will try longer pours to see if that gets me there. Good suggestion. Thx.

  8. #8
    Mal Dimal's Avatar
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    What sort of clearance from the shower-screen are you getting with the 15g dose mate?

    Mal.

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    Enough so that there is a slight impression of the shower screen edge on the filter basket at the end of the shot...

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    I like my 15 g VST but have noticed that it requires a noticeably finer grind than the 18, 20 and 22 g baskets. I also second the importance of good distribution.
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    Quote Originally Posted by kwantfm View Post
    I like my 15 g VST but have noticed that it requires a noticeably finer grind than the 18, 20 and 22 g baskets. I also second the importance of good distribution.
    Good to hear someone is getting positive results. What do you usually use the basket for, espresso or some other drink?

    Would love to make great espresso from this basket. I know it can do it, just can't manage to find that magic sweet spot again.

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    I use it for everything espresso related... the range of drinks required on a weekend with neighbours and friends ranges the full spectrum: ristretto, espresso, long black, macchiato, flat white.

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    Ok. Sounds good.

    just spent an afternoon pumping out shots. Got the vst to taste really nice, with creamy crema.

    Went back to the 20 gram to compare, and I still can't do better than this basket.

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    Quote Originally Posted by tobeanornottobean View Post
    Enough so that there is a slight impression of the shower screen edge on the filter basket at the end of the shot...
    Unfortunately mate, that means nothing and can't be used as a guide...

    I probably should not have assumed that you understood. What I meant was, after dosing, distributing and tamping and then locking your Group Handle in place but NOT pulling the shot, what clearance is there between the top of the dry puck and the bottom of the Shower-screen?
    You should be aiming for around 1.5-2.0mm; or about the thickness of a five cent piece...

    Mal.

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    Quote Originally Posted by Dimal View Post
    Unfortunately mate, that means nothing and can't be used as a guide...

    I probably should not have assumed that you understood. What I meant was, after dosing, distributing and tamping and then locking your Group Handle in place but NOT pulling the shot, what clearance is there between the top of the dry puck and the bottom of the Shower-screen?
    You should be aiming for around 1.5-2.0mm; or about the thickness of a five cent piece...

    Mal.
    no. i understood perfectly... If trying to work out if your dosing low or high in relation to your screen, determining if a slight impression of the screw/screen post shot is a good indication.
    As per the five cent rest, I get a slight impression at 15gm. Slightly more at 16, obviously.
    the thing about vst baskets, as you might already know, they are designed to work within quite specific parameters.
    Last edited by tobeanornottobean; 17th January 2016 at 05:24 PM.

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    Post shot indications are pretty worthless in my view...

    I can achieve that kind of impression with shots dosed 60-120% of the baskets' nominal designed capacity so not a lot of use really...

    Mal.
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    Quote Originally Posted by kwantfm View Post
    I like my 15 g VST but have noticed that it requires a noticeably finer grind than the 18, 20 and 22 g baskets. I also second the importance of good distribution.
    +1 (10 char limit text)
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    Quote Originally Posted by Dimal View Post
    I can achieve that kind of impression with shots dosed 60-120% of the baskets' nominal designed capacity so not a lot of use really...
    Ymmv
    if I underdose too low things tend to get pretty swampy.
    moot point though I'd say. I think I can remove clearance as an issue.
    distribution is another thing.
    wdting like a freak has definitely helped. I was only giving it a passing nod previously.
    the results are now vastly improved. Not sure it's as charismatic as the stock basket yet, but that may change.

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    Quote Originally Posted by tobeanornottobean View Post
    the thing about vst baskets, as you might already know, they are designed to work within quite specific parameters.
    That's the theory, but the practice can be different. For example, I have a range of VST baskets (15, 18, 22) and I've been told (on this forum) that you should be able to grind the same and dose the same and get the same pour time. Supposedly that's how they were designed. Well, it just ain't so, at least not here. The larger the basket the coarser the grind. Not by a huge amount, but by enough.

    So for each of my VSTs, I dose to the 5c test, and then use this quantity of gms, and adjust the grind to give the right pour time / extraction ratio. Using my M4D, the difference is about two half-turns coarser between the 15 and 18 and two to three between the 18-22.

  20. #20
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    Was more referring to the dose range in those baskets, which I understand to be about +/- a gram (i.e. you can dose around 14 – 16 grams for a 15 gram basket).

    If you grind and dose the same grams in the same basket you should definitely/generally get the same pour time. In different baskets...same grind - I would expect a dif. story?
    Last edited by tobeanornottobean; 19th January 2016 at 02:03 PM.

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    I use a 15g ridgeless VST every morning - personally I prefer it to the 22g or any stock baskets I have.

    After sorting out my dosing method a year ago the extractions have been almost perfectly consistent shot to shot. Basically, I dose to ~1/2 full, shake side to side a bit to distribute and tap on a teatowel to settle the grinds. Then dose till just overflowing, scrape flat with a chopstick, gently tap once more (careful not to send grinds to one side) and tamp. I worked it out after reading that VSTs have holes all the way to the side so that you extract the entire puck evenly, giving a more efficient extraction (higher % of total dissolved solids). The problem is that traditional dosing methods normally self-remedy this by leaving a slight mound of grinds in the centre, hence slowing the flow in the middle (or by a nuating tamp). If done on a VST you will clearly see some 'gushing' from the outside holes. This is why you need to scrape it perfectly flat, without pre-compacting the grinds.

    Anyway each to their own but I'm happy enough with my method to stop tweaking it. The simplest way to give an even layer of grinds will be the best, overcomplicating it with unnecessary tapping, fluffing etc just results in more serious problems. Using a naked PF is essential to see what is happening.
    Last edited by burr; 22nd January 2016 at 10:01 AM.
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    Interesting. Good to hear there is hope. Guessing you wouldn't be able to relate how many grams of coffee this dosing method generally produces for you?

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    Just weighed it then and it looks like it is in the range of 15.3-15.6 grams, although this probably varies depending on the beans. Its good to know that this is in the 15-16 g range used for the basket (I never bothered to check)!

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    cool. i'll give your method a go. I'm dosing to 15 grams bang on, but weighing before I load the basket.

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    Quote Originally Posted by burr View Post
    Just weighed it then and it looks like it is in the range of 15.3-15.6 grams, although this probably varies depending on the beans. Its good to know that this is in the 15-16 g range used for the basket (I never bothered to check)!
    G'day burr

    +1. I tested all my VSTs sets when I first got them (medical refractometer) and all four 15s were actually optimised at 15.4g on that test gear. A similar ratio existed for all the other sizes. FWIW, I do almost the same as you: dose to 15.4 and adjust grind / tamp to get the pour correct. Tinkering with preinfusion also helps a lot.

    The VSTs remain the only basket I know where the actual dose height (i.e. clearance to group) is almost completely irrelevant. Different roasts have different densities and solubility so essentially the level will vary massively anyway. The 5 cent test is a traditional "Italian dark roast" relic in my view as that is where it is closer to correct.



    Quote Originally Posted by tobeanornottobean View Post

    yeah, bought my vst with a custom Pullman tamper so no issue with fit. I grind into a cup so I can weigh (15g) and empty into a jam funnel. Also played with 16 g but that's not helping.

    will try longer pours to see if that gets me there. Good suggestion. Thx.

    Does anyone have any experience using the 15gm basket, over say the 18 or 20?

    ive also noticed a few holes in my puck using the vst that don't happen on the stock basket. Wonder if this is part of the problem.

    ...advice appreciated!
    G'day tobeanornottobean

    I tinkered / edited your earlier posts for clarity.

    Another related factor: VSTs almost require the use of a flat tamper or they go "uber finicky" on the distribution. If your Pullman has a curved base, it will never be consistent. My old RBs have a US and a Euro curve, neither work worth a damn on a VST. All my (and cafes and friends) Pullman 316s are flat bases and they all work with no effort.

    The holes in your puck are evidence of channeling (as others pointed out). Two main causes: poor distribution and (rarely, thank goodness) too much direct power from the group's "water jet". The latter can usually be sorted by a thorough clean and A to Z maintenance, perhaps followed by a replacement shower screen (or two in some cases). If that fails, the only reliable "quick & temporary fix" I found was to increase the height of the puck. In your case I would suggest you get a 22g VST and play with that - if it makes a huge difference over the 15g then it points to the machine having that issue. Replacing whole groups gets expensive...

    Other VST sizes: On all but two machines I tested using the same dosing percentage and roast (and grinder, tamp etc.) the only real differences across the VSTs was the coffee strength - no flavour aberrations worth noting. After a clean, both those machines "fell into line" with the rest. Once I have the setup correct on the grinder then I can interchange any of the VSTs from my usual 7g through to my 22g without adjusting anything other than matching the dosing to the basket. If I get really anal, a one notch change on my Vario MAY make a minor difference (the Vario has around 50 espresso settings for grind).

    Hope this helps you get the consistency you deserve.


    TampIt
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  26. #26
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    G'day tampit
    cool you are using a 7 gram. I really want to buy one and explore this whole Italian standard thing a little. See what kind of coffee I can get. Also great that you can change baskets but keep the same grind settings, as long as you match dose to basket correctly. Tell me about the espresso you pour from a 7 gram. Do you use ratios or mls to judge when to end the pour?
    re my issue - I have fixed the holes I was getting via wdt. Because of the clumps my compak seems to generate, it's hard to distribute in the 15 gram by tapping or collapsing effectively. Interesting that I do not wdt on my stock 20ish gram basket and it does not get holes, and produces some decent shots imho. I'm now getting ok results from the 15 gram, however believe it can get better. Go through plenty of coffee getting in the zone.

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    Quote Originally Posted by tobeanornottobean View Post
    G'day tampit
    cool you are using a 7 gram. I really want to buy one and explore this whole Italian standard thing a little. See what kind of coffee I can get. Also great that you can change baskets but keep the same grind settings, as long as you match dose to basket correctly. Tell me about the espresso you pour from a 7 gram. Do you use ratios or mls to judge when to end the pour?
    re my issue - I have fixed the holes I was getting via wdt. Because of the clumps my compak seems to generate, it's hard to distribute in the 15 gram by tapping or collapsing effectively. Interesting that I do not wdt on my stock 20ish gram basket and it does not get holes, and produces some decent shots imho. I'm now getting ok results from the 15 gram, however believe it can get better. Go through plenty of coffee getting in the zone.
    G'day again tobeanornottobean

    7g: Yep, I get amused when so many posters on CS worship everything else Italian and then run 15g+ baskets and make comments like "my single sits in a drawer unused". Unlike the Italians, I mainly use light to medium SO roasts. I am old school (started espresso in 1970) so I actually judge the pour to work out when to cut the shot. When I initially dial a setup in, I aim for 22 to 25 seconds shot time not counting preinfusion and then I simply pump them out. You will need to rig up a special tamper for the 7g VST. Here are a couple of photos of mine (7g is in the middle of the group shot):- (would be, the photos appear at the bottom in reverse order without a link I can move for some bizarre reason).

    I did a stack of measurements at least two or three years ago now. The VST extraction ratio was 22%+. The best drinkable shot I could get out of any of my other baskets (an aftermarket one starting with S) was 16% - and that was a one-off fluke. Anyway, at that time the 7g was giving almost exactly 28g of weight on every shot. As the VST does extract up to 50% more out of any given roast, that is almost exactly an equivalent to the Italian standard: they specify 30ml volume including crema however most of their dark roasts use some Robusta beans (more crema), so 28g weight should be about right using 100% Arabica in a VST. Clearly different roasts will end up with quite different readings, so as long as the resulting cuppa is balanced to your tastes I would not get too carried away with the measurements.

    The main reason your 20g basket is easier is due to the greater depth I alluded to earlier. Put simply, you can do a worse distribution job and get away with it more often if you have a larger buffer to hide the evils. I am blessed with a pair of Mahlkonig Varios so static / clumping / spraying everywhere is only an old memory now: until I am asked to setup a cafe somewhere by a friend... (sigh, if I see one more SJ needing an A to Z plus burrs I will scream).

    Another fix which may help you: use progressive tamping (just like an LM Swift grinder does) by lightly tamping every 2mm or so of coffee fluff. It tends to minimise a whole pile of grinder snafus (among other advantages).

    Enjoy your cuppa


    TampIt
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    Last edited by TampIt; 23rd January 2016 at 01:15 AM. Reason: photo snafu.

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    Hmm. almost bought a vario actually. Was talked out of it by the sales guy oddly enough. I always saw one in my life though. maybe one day.

    re tampers. My tamp is a flat base.

    I also see a 7grm basket tamp in my future at some point.

    re my stock single basket, I've not had great joy yet. Perhaps due to a lack of decent tamp. I used the top end of the plastic one.

    my Italian machine's instructions do advise putting 7grams in the basket, so clearly it's designed to do this. My limited experience at that dose gave me a definitely tasty, but mainly crema less outcome...

  29. #29
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    Quote Originally Posted by tobeanornottobean View Post
    Hmm. almost bought a vario actually. Was talked out of it by the sales guy oddly enough. I always saw one in my life though. maybe one day.

    re tampers. My tamp is a flat base.

    I also see a 7grm basket tamp in my future at some point.

    re my stock single basket, I've not had great joy yet. Perhaps due to a lack of decent tamp. I used the top end of the plastic one.

    my Italian machine's instructions do advise putting 7grams in the basket, so clearly it's designed to do this. My limited experience at that dose gave me a definitely tasty, but mainly crema less outcome...
    G'day again tobeanornottobean

    Glad your Pullman is a flat base. Essentially that means that if you can somehow get rid of the static then using your VST double should be fine.

    A couple of thoughts: VSTs are also "very responsive" (i.e. hairtrigger) to particle spread variations - particularly the level of fines - which is why I initially bought my first Vario. As mentioned earlier in this thread, you need to grind much finer ('bout 30% finer) when using a VST. That means a lot of the traditional grinders, which were designed with a wide particle spread and a standard espresso grind, do not play well with a VST (i.e. it is beyond their design parameters). Perhaps yours is playing havoc with that as well as static - wouldn't be the first time I ran into that gremlin... Back to static: a lot of grinders have an anti static screen - and if so, half the time removing it lowers the static. No idea why, however RF is pretty strange sometimes so perhaps static is similarly elusive.

    Anyway, the main reason for this post:
    7g tamper: As long as the basket is actually tampable (if that is a word), then almost anything may be used at a pinch. I used a Smartwater "guava & lime" bottle about 1/3 full for over a year on my 7g VST (the water balanced the tamp for weight). Although matching any side taper helps (the smartwater bottle did not do that) it is not essential. The issue is that some of the single baskets have such a shallow slope that no tamper can work - Java"font of knowledge"Phile had a photo of his single recently which I would regard as untampable. Perhaps your single fits into that camp? Things Coffee (site sponsor) has photos of the VST 7g so you can see that it is an almost cylindrical "plug" in the centre then a shelf which acts as an adaptor to fit a standard 58mm group. 7g of almost every roast sits well "below the shelf", so you need some tamper to fit in that smaller size (roughly 40mm in diameter).

    In terms of crema, using Arabica beans the freshness of the beans and the darkness of the roast has more to do with the quantity of crema than every other factor combined. The 7g VST does not inherently lack crema, and whatever crema you get tends to be very persistent when you dial it in correctly. Actually, the crema persists for far longer than any of the traditional baskets I have.

    Hope this clarifies and helps, as it strikes me you now have enough info to sort your issues out and even make a bit of progress.

    TampIt

  30. #30
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    Cheers Tampit

    Yes, the slope on my single seems to prevent proper tamping at a 7g dose (grinds go up the slope). Yet I ask myself, why design something if it doesn't do the job they intend it to do. I suspect it must work, but needs the right hand.

    Not sure what progress I'm making. Seem to be going backwards. Enjoying this basket immensely with milk drinks, hopefully will work it out for espresso.
    Last edited by tobeanornottobean; 24th January 2016 at 02:22 PM.

  31. #31
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    Behmor Brazen - $249 - Free Freight
    Update on my thinking re this issue...
    plan on buying a 14 gram precision basket from talk coffee to see if it will let me grind a bit coarser. Hoping a trade off in extraction % for less channelling will lead to an overall better brew.
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