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Thread: Dosing Question

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    Dosing Question

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Ive been making coffee for a couple of years now, for a year or so with a Giotto and a Mazzer Mini. I still find that I have problems dosing consistently. No matter what technique I try, I find with the Mazzer, even with a fancy plastic funnel attached to its outlet, drops the grinds so oddly that knowing what is half or three quarters full before tapping it down prior to grinding again and topping up is impossible to do consistently. Just to be clear my technique is to grind into the basket till almost full, tap the group handle down twice to settle the grounds, then grind again and tap down before levelling off and tamping.
    I find even the smallest of margins in volume makes quite large differences to the pour, much more so than tamping pressure variables.
    Has anyone had the same issue and resolved it?
    The only thing I can think of is just to grind till well over the top of the basket and then to tap down and level off but Im worried that would mean channelling in the coffee as the grounds wouldnt be as compacted as when settling the grounds twice.
    I am not sure I have made any sense.

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    Re: Dosing Question

    Hehe you make sense! I think we have all gone (or in my case still are going) through it.

    Two things I can think of are 1. Try levelling with a semi circular object (see Scottie Callaghans barista tools, aka grinder lid or yoghurt lid or tuppaware lid that your wife mysteriously cant find anymore). Vary the diameter up to flat until you find the one that works. 2. How about weighing the whole pf? Get some accurate scales and tare them with an empty pf.

    And just thought of 3. Use your grinder timer. The MM is a little hard to set but should give reasonably consistent results if you dont change the grind.

    Which brings me to another point in my wandering brain! Are you sure the changes in volume arent related to old grinds in the doser or some other technique issue? I find that not paying attention to my Giotto will only change a 25s pour by <5s either way...

    HTH!

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    Re: Dosing Question

    Hi gbatterly

    I am 2.5yrs in with the same set up - ie manual mm and Giotto. I have found 2 issues impacting pour times.
    - Grind consistency - I dose each time I make a coffee. I have found that the beans bouncing around causes grind variation and pour variation. I have been experimenting with different weights on the beans to get consistency - this seems to be working.

    - Dosing is critical as you say. My technique is to grind a known quantity of beans each time - with the double basket, I use 2 level scoops with the Giotto spoon. I have weighed this many times and it is in the range of 18 to 20 gms depending on the beans and scoop volume. I grind the beans into the doser chamber and then discharge into the portafilter. With my mm, I find after about 3 to 4 trigger pulls, there is a lull in the coffee discharge - at this point I do 2 level taps on the mm portafilter prongs. I then discharge rest of coffee and then tap 2 times again.

    - prior to tamping, I use scottie tool #4 to level, and then use this to set grinder and pour times. Once set, I find this pretty consistent. Naturally, there are changes day to day - sometimes Ill tweak the grind setting and sometimes Ill change which Scottie tool I use - but overall, I do get pretty consistent pour times.

    Having said that, Im still very much learning and tweaking what I do.

    Hope this is of some use

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    Senior Member GregWormald's Avatar
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    Re: Dosing Question

    If very small differences in volume are making large differences in the extraction, then you *may* be right on the edge of over-dosing.

    I suggest you try the 5 cent test. When you have the volume right, then you can work on being consistent.

    Greg

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    Re: Dosing Question

    Thanks for all the advice. I think the first thing to do is the 5 cents test to make sure Im not overdosing. I dont think I am as the group handle always gets perpendicular without much of a shove and having had the Giotto for a while I have a feel for when its overdosed but Ill see tomorrow morning.

    Im already using a Scottie tool to level before tamping.

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    Re: Dosing Question

    Oops, looks like I was overdosing. Which was a surprise. I thought I had read somewhere that with a Bogav Tamper if its level with the top of the basket then youre good. Well I wasnt. The 5 cents piece was buried good and proper. You could have put a gravestone over it and held a service.
    Thanks Greg.

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    Senior Member saoye's Avatar
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    Re: Dosing Question

    Quote Originally Posted by 7D787B6E6E7F68767F631A0 link=1330693048/5#5 date=1331036415
    I thought I had read somewhere that with a Bogav Tamper if its level with the top of the basket then youre good. Well I wasnt. The 5 cents piece was buried good and proper
    Also give the rice check a go as an alternative. Might help. :)

    http://www.youtube.com/watch?v=lJzmcM2AUS0

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    Re: Dosing Question

    Quote Originally Posted by 787D7E6B6B7A6D737A661F0 link=1330693048/5#5 date=1331036415
    Oops, looks like I was overdosing. Which was a surprise. I thought I had read somewhere that with a Bogav Tamper if its level with the top of the basket then youre good. Well I wasnt. The 5 cents piece was buried good and proper. You could have put a gravestone over it and held a service.
    Thanks Greg.
    Have a read through this short thread http://coffeesnobs.com.au/YaBB.pl?num=1274249469/7 gives a good overview of the 5 cent piece test. :)

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    Re: Dosing QVSTuestion

    It seems Im going to have to significantly change my technique. I dont know if its my VST basket but whatever technique I use I am overdosing. Even with just settling the grounds right at the end and then tamping AND using the Scottie tool number 6 before tamping the 5 cent piece is still almost completely embedded in the coffee.

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    Re: Dosing Question

    Quote Originally Posted by 474241545445524C4559200 link=1330693048/8#8 date=1331120907
    the 5 cent piece is still almost completely embedded in the coffee
    just to say the obvious: this is BEFORE you extract right? You just lock in the pf and then remove straight away?

    Quote Originally Posted by 474241545445524C4559200 link=1330693048/0#0 date=1330693048
    The only thing I can think of is just to grind till well over the top of the basket and then to tap down and level off
    theres nothing wrong with doing this - is that what you tried in your last post? You may waste a few grinds but who cares if it means youre going to get a consistent dose?! How curved is the #6? I use my hopper lid which has a diameter of about 15cm I think.

    What sized VST basket are you using?

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    Re: Dosing Question

    Yes, it is before I extract.

    Its the 18g VST basket.

    I have changed back to the ridged stock Giotto basket to see if I can have more success that way.

    However, Ive come across a new issue. My group handle goes past the perpendicular 6 o clock position, such that to have it in the 6 o clock position would mean it wouldnt pour right. The group handle sits about 5.30, i.e it swings past the perpendicular a bit. I have noticed that no matter how low I dose, when I lock the group handle in to this position the imprint of the shower head is always on the coffee (before water). So the 5 cents piece is ALWAYS going to be buried.

    I hope this makes some sense.

    The only way I can get the pre extraction coffee so low that the shower head does not make an imprint is by dosing so that when I have tamped the coffee is noticeably under the ridge of the basket. I know this cant be right.

    Addendum: I have just read through the 5 cent piece thread and someone else posted a picture of how low they needed to go and it seems it is noticeablu under the ridge of their basket.

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    Re: Dosing Question

    Quote Originally Posted by 3A3F3C2929382F3138245D0 link=1330693048/10#10 date=1331206962
    no matter how low I dose, when I lock the group handle in to this position the imprint of the shower head is always on the coffee
    Keep going lower? How many mm from the top of the basket are you? I have an 18g ridgeless VST and I estimate Im tamping 8.5mm from the top, or if the basket is 23mm deep about 14.5mm deep in coffee.

    Now YMMV depending on lots of things, but thats where I am right now. Its possibly a little low.

    Quote Originally Posted by 3A3F3C2929382F3138245D0 link=1330693048/10#10 date=1331206962
    The group handle sits about 5.30
    Hopefully this is just a bit of seal wear and not collar wear - I dont know how these things go. When I put on my new seal I moved from 6 oclock to 6:30, but now its worn in around 6.

    Quote Originally Posted by 3A3F3C2929382F3138245D0 link=1330693048/10#10 date=1331206962
    noticeablu under the ridge of their basket
    Is this a Giotto / VST picture? since it changes a lot from machine to machine.

    Perhaps there is a fellow snob nearby who would like to make some coffees at your / their place and have a look?

  13. #13
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    Re: Dosing Question

    I have a Bezzera, am using an 18 gram VST basket, dosed with 18 grams of ground coffee the top of the coffee when tamped sits level approx 8mm below the top of the basket, this just clears the shower screen by approx the thickness of a 5 cent piece and gives me excellent results. :)

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    Re: Dosing Question

    How interesting that our measurements are so close! 8 vs 8.5mm!

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    Re: Dosing Question

    Can you take some photos? Maybe one of your tamper in the handle, one of your tamped bed of coffee, and of the 5 c piece after locking in and taking out?
    After some testing etc I found I needed to dose way lower on my Oscar than I thought I should be...

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    Re: Dosing Question

    Ill post some pictures this weekend.

    Thanks for all the advice.

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    Re: Dosing Question

    Quote Originally Posted by 2A222A2D2721430 link=1330693048/13#13 date=1331217231
    How interesting that our measurements are so close! 8 vs 8.5mm!
    Mine may well be 8.5mm, depends on the fineness of the grind, finer equals a little deeper, perhaps closer to 9mm, once youve figured out the setting its not something you need to check again, it just becomes second nature.
    I might measure a shot with my vernier gauge later and post results. :)
    Just checked the depth with a vernier, varies between 8.5mm and 9.5mm depending on the grind.
    I hear you ask how do I know I get a similar result each and every time, I weigh the beans for every* shot, no exceptions.

  18. #18
    Senior Member GregWormald's Avatar
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    Re: Dosing Question

    Good work.

    Given the precision ;D with which coffee machines are made, the proper dose for each machine is likely to vary up to a couple of mm.

    Find the right level for your machine--handle, group head, gasket, basket, screen, etc.--and stick to it.

    Weighing each dose will get you close, but different densities of the beans and fineness of the grind can give different volumes for the some weight. A slight under dose is probably more reliable than trying to get it perfect.

    Greg

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    Re: Dosing Question

    I think I might be getting there. Sometimes when Im in the middle of a "coffee problem" I cant see the woods for the trees. It seems grinding to a mound and rapping twice and then topping up and levelling gets the right amount. Now when I put the group handle in there is no imprint of the shower screen on the coffee before extraction. With a 5c piece on top it leaves a small imprint. I will post pics later just to make sure I am on the right track.

  20. #20
    Senior Member GregWormald's Avatar
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    Re: Dosing Question

    Generally a small imprint is fine, as long as the coin isnt pushed level with the coffee.

    I do prefer to have it *just* not indenting though. This leaves me a bit of leaway for the bean and grind differences as I dose by weight.

    Greg

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    Re: Dosing Question

    Quote Originally Posted by 45706765556D706F636E66020 link=1330693048/19#19 date=1331543498
    I do prefer to have it *just* not indenting though.
    Maybe use a 10c piece and have it go a little further in. Its pretty hard to tell if its just "not" indenting.

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    Re: Dosing Question

    Quote Originally Posted by 637871676469100 link=1330693048/20#20 date=1331587676
    Quote Originally Posted by 45706765556D706F636E66020 link=1330693048/19#19 date=1331543498
    I do prefer to have it *just* not indenting though.
    Its pretty hard to tell if its just "not" indenting.
    Not really, give it a bit of thought, youll work it out. ;)

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    Re: Dosing Question

    Quote Originally Posted by 6A565F4752330 link=1330693048/21#21 date=1331593293
    Its pretty hard to tell if its just "not" indenting.

    Not really, give it a bit of thought

    Please explain!!
    If the shower screen isnt touching the coin enough to leave some sort of imprint how do you know how much its missing it by.
    Do you overtighten the group handle to screw it higher?
    This would then depend on the "thread angle" of the group, introducing another variable.

    Wouldnt it be easier to use a thicker tool (coin) ;)

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    Re: Dosing Question

    Quote Originally Posted by 726960767578010 link=1330693048/22#22 date=1331596422
    Please explain!!
    If the shower screen isnt touching the coin enough to leave some sort of imprint how do you know how much its missing it by.
    Do you overtighten the group handle to screw it higher?
    This would then depend on the "thread angle" of the group, introducing another variable.

    Wouldnt it be easier to use a thicker tool (coin)

    It depends on the machine
    Just experiment a little and when you have the correct depth ? memorise it or place a mark on your tamper (if possible) for future reference

    See drawing -

    KK


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    Re: Dosing Question

    Quote Originally Posted by 684C454546467C684C504E4C230 link=1330693048/23#23 date=1331600309
    It depends on the machine
    Just experiment a little and when you have the correct depth ? memorise it or place a mark on your tamper (if possible) for future reference
    Good advice KK

    But I think you were missing the point of my reply.
    I was just trying to find out how you could tell if a coin on top of the puck was "just not indenting".
    Thought it would be easier to use a thicker coin (or whatever) and use the indent depth as a better reference point.

    Re-read from Reply #19

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    Re: Dosing Question

    Quote Originally Posted by 7F646D7B78750C0 link=1330693048/22#22 date=1331596422
    If the shower screen isnt touching the coin enough to leave some sort of imprint how do you know how much its missing it by.
    Dose as little as possible while still having the 5c piece pressed, dose again a bit less so that it is "only just" not pressed into the puck. My second crack worth to Jons 5c trick ;)

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    Re: Dosing Question

    Quote Originally Posted by 352E2731323F460 link=1330693048/24#24 date=1331602114
    Good advice KK

    But I think you were missing the point of my reply.
    I was just trying to find out how you could tell if a coin on top of the puck was "just not indenting".
    Thought it would be easier to use a thicker coin (or whatever) and use the indent depth as a better reference point.
    I dont use a 5 cent piece never have
    I just experiment with coffee puck depth until the correct level is ascertained for that particular machine

    A fine imprint is fine - as long as the puck is not broken
    It takes 2 to 3 goes and I am right to go
    KK

  28. #28
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    Re: Dosing Question

    I am realizing that paying attention to bean weight and not paying attention to extraction weight allows a big variable in the actually volume. If I pull a triple into a 3.5 oz shot glass with 3/4 of the pull being crema it settles to less than 2oz by volume, so weight is the only way I can get the desired amount.

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    Re: Dosing Question

    Quote Originally Posted by 5E7A737370704A5E7A66787A150 link=1330693048/26#26 date=1331602889
    Quote Originally Posted by 352E2731323F460 link=1330693048/24#24 date=1331602114
    Good advice KK

    But I think you were missing the point of my reply.
    I was just trying to find out how you could tell if a coin on top of the puck was "just not indenting".
    Thought it would be easier to use a thicker coin (or whatever) and use the indent depth as a better reference point.
    I dont use a 5 cent piece never have
    I just experiment with coffee puck depth until the correct level is ascertained for that particular machine

    A fine imprint is fine - as long as the puck is not broken
    It takes 2 to 3 goes and I am right to go
    KK
    Can I just check what you mean by a "fine imprint"? of a 5c piece or the shower screen?

  30. #30
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    Re: Dosing Question

    Quote Originally Posted by 767370656574637D7468110 link=1330693048/28#28 date=1331632710
    Can I just check what you mean by a "fine imprint"? of a 5c piece or the shower screen?

    I noted that I do not use a 5 cent piece I use the coffee puck itself
    When you lock in the fully prepared handle, you want the puck to just miss the water screen or if it touches it should be by a hairs whisker

    I am going to make it easy for you

    You have a Giotto Premium
    1) Tamp 8mm deep into the basket
    You can mark your tamper on the side with a texta as a guide
    2) Lock the handle as you normally do
    3) Unlock and see if the puck has a mark on it or not

    Adjust the level higher or lower as required and repeat the process until satisfied you have the correct level

    4) Note the depth + mark your tamper
    5) and now you have the correct tamp level for your machine

    KK

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    Re: Dosing Question

    What about machines with big bolts sticking out the bottom of the shower head? At work we have a gaggia Deco commercial machine with a bolt that leaves an indentation no matter how low you dose. Is there an exception to machines like this?

    I guess what i want to know is there any scenario where contact with the shower screen is completely normal and designed for?

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    Re: Dosing Question

    Quote Originally Posted by 3D3F3D2024500 link=1330693048/30#30 date=1331638565
    What about machines with big bolts sticking out the bottom of the shower head? At work we have a gaggia Deco commercial machine with a bolt that leaves an indentation no matter how low you dose. Is there an exception to machines like this?

    I guess what i want to know is there any scenario where contact with the shower screen is completely normal and designed for?
    Normally I would consider this a design afterthought and would recommend that one changes the big nut to a flush fitting screw

    If this is not possible always use the screen as your guide for correct tamp depth level
    Even if the bolt head digs into the puck

    KK

  33. #33
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    Re: Dosing Question

    Quote Originally Posted by 5153514C483C0 link=1330693048/30#30 date=1331638565
    What about machines with big bolts sticking out the bottom of the shower head? At work we have a gaggia Deco commercial machine with a bolt that leaves an indentation no matter how low you dose. Is there an exception to machines like this?

    I guess what i want to know is there any scenario where contact with the shower screen is completely normal and designed for?
    Last question first--I cant imagine that. Even a small amount extra or less is going to change the extraction radically as the grounds expand and have nowhere to go. (See the original post.)

    Some machines seem to work OK with bolts, but Id be afraid that any real pressure would be likely to fracture the puck and lead to channelling. The italians do not dose as high as we do, they seem to stick to the 14 gm doubles fairly well (I was there last year and watched closely to see what I could learn) and in most baskets this will clear the bolts.

    Greg

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    Re: Dosing Question

    i like this thread!

    whats the consensus on the look and feel of the puck after extraction and its relation to dose?

    ive always thought (been taught) that after extraction the puck should have a definite imprint and be firm to touch but able to be compressed a mm or 2 (by a finger)

    after following the rice test and doing the 5c im now dosing much much lower than im familiar with (couple mm below the ridge on my baskets); and ending up with more sloppy pucks that i know id be able to push my finger up to the knuckle into...


  35. #35
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    Re: Dosing Question

    Behmor Brazen - $249 - Free Freight
    Quote Originally Posted by 44425F49525F4901090800300 link=1330693048/33#33 date=1331729723
    i like this thread!

    whats the consensus on the look and feel of the puck after extraction and its relation to dose?

    ive always thought (been taught) that after extraction the puck should have a definite imprint and be firm to touch but able to be compressed a mm or 2 (by a finger)

    after following the rice test and doing the 5c im now dosing much much lower than im familiar with (couple mm below the ridge on my baskets); and ending up with more sloppy pucks that i know id be able to push my finger up to the knuckle into...
    Many moons ago I used the 5c test to establish my dose level, I tamp lightly, cant give an exact figure but if I had to guess I doubt it would be more than 5kg, after pulling a shot my pucks show moisture on top which the puck absorbs within a few seconds, the puck knocks out clean, dry and intact, showing no signs of channeling. :)



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