Dosing Question

[gbatterley]

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.

[iaindb]

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!

[argon]

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

[GregWormald]

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

[gbatterley]

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.

[gbatterley]

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.

[saoye]

Re: Dosing Question

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

[Yelta]

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.

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.

[gbatterley]

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.

[iaindb]

Re: Dosing Question

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?

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?

[gbatterley]

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.

[iaindb]

Re: Dosing Question

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.

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.

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?

[Yelta]

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.

[iaindb]

Re: Dosing Question

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

[Bames]

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...