Controlling shot extraction pattern

[Abe Carmeli]

When I watch the bottom of the basket during a shot, I can clearly see an extraction pattern. For the longest time it was from the basket outside perimeter to the center. No matter which tamper I used. This issue came up before, with no clear answer as to what is causing it. One hypothesis was that it had to do with the pattern of water exiting the shower screen.

Only after getting the M3 grinder, I finally figured out what that was. I am now able to control the extraction pattern and change it by changing my leveling/distribution technique. Here's how it works:

An extraction pattern from the outside in (where the center of the basket is the last to saturate) is caused by what I call Schomer's Crater. Schomer advocates to control dosing as follows: Overfill the basket, do your NSEW leveling/distribution, and then shave off the access coffee with a bowed finger sweep across the basket rim. This movement will leave the basket surface with a shallow crater. As you sweep to shave off the access, your bowed finger pushes the coffee down where at the center of the basket it now becomes more dense than in the perimeter. (my guess, no density study done). Whatever the cause is, that technique always results with the center being saturated last.

To avoid the above saturation pattern, and reach simultaneous and even saturation across the basket bottom, one needs to leave the basket surface level without Schomer's crater. Now, that becomes a problem when you are dealing with a basket like the standard 14 grams Faema, and you do not want to updose. Most grinders will end up with 17-18 grams of coffee in the basket after leveling.

Here's where the Versalab M3 grindermade a difference in my case: It delivers fluffier grounds than the Mini. Those grounds occupy larger volume in the basket than grounds out of the Mini. Leveling the surface leaves 14-15 grams in the Faema basket, and as expected, the extraction pattern is simultaneous saturation.

There may be a way to do the same thing with a standard grinder (have simultaneous saturation without updosing). Any ideas?

[papalatte]

It's funny I've doing the same thing on my own. Today my Yurg. has come out fluffy ( don't know why ) Strange but there seems to be an interconnectivity between people.

[malachi]

Stockfleth's Move for distribution.

[Abe Carmeli]

Stockfleth's Move for distribution.

How is this going to solve the updosing problem? How do you dose with Stockfleth to get 14-15 grams and avoid a crater?

[ant]

From what I can gather when observing stockfleths.mov-

It looks like both the dosing method and the distribution technique are circular. This (hopefully) results in an even density in the coffee puck before tamping. From my experience on a super jolly mazzer it seems to be quite consistent when grinding per shot. If I grind for several orders in the one go however, I lose consistency in how the grind falls from the doser and that throws out any consistency I have when practicing the stockfleth method. Anyone care to donate a robur to a pisspoor barista?

[malachi]

Stockfleth's Move for distribution.

How is this going to solve the updosing problem? How do you dose with Stockfleth to get 14-15 grams and avoid a crater?

What updosing problem?

A distribution method shouldn't be used for dosing purposes. It's purely for distribution.

I'm confused.

You dose as you dose (so dose 15 grams, say) and then you distribute as you distribute (in this case, as noted, in a rotational manner).

Stockfleth's seems (in my experience) to result in a more even density throughout the basket.

[Abe Carmeli]

What updosing problem?

A distribution method shouldn't be used for dosing purposes. It's purely for distribution.

I'm confused.

You dose as you dose (so dose 15 grams, say) and then you distribute as you distribute (in this case, as noted, in a rotational manner).

Stockfleth's seems (in my experience) to result in a more even density throughout the basket.

If I dose 15 grams, the grounds do not fill up the basket. Stockfleth's as I see it counts on a basket filled up to the rim with a little mound above it. The 14-15 grams dosage, or any dosage that does not fill the basket to its rim, will make the circular leveling movement impossible, as your finger will not touch the coffee grounds at all.

[barry]

If I dose 15 grams, the grounds do not fill up the basket.

get a nuova simonelli double basket. that maxes out around 15 grams.

[malachi]

What updosing problem?

A distribution method shouldn't be used for dosing purposes. It's purely for distribution.

I'm confused.

You dose as you dose (so dose 15 grams, say) and then you distribute as you distribute (in this case, as noted, in a rotational manner).

Stockfleth's seems (in my experience) to result in a more even density throughout the basket.

If I dose 15 grams, the grounds do not fill up the basket. Stockfleth's as I see it counts on a basket filled up to the rim with a little mound above it. The 14-15 grams dosage, or any dosage that does not fill the basket to its rim, will make the circular leveling movement impossible, as your finger will not touch the coffee grounds at all.

1) What basket are you using?
2) Why is it critical for you to dose that particular amount?
3) Are you settling the grounds in some way (tapping or shaking the portafilter, etc)?

[Abe Carmeli]

1) What basket are you using?

All double baskets: L/M, Ridgeless, and OEM Faema.

2) Why is it critical for you to dose that particular amount?

I like some Ristrettos at that dosage. But this is more of a general question: How can you properly distribute coffee when your dosage does not fill the basket.

3) Are you settling the grounds in some way (tapping or shaking the portafilter, etc)?

Not for a 15 grams shot.

[Abe Carmeli]

get a nuova simonelli double basket. that maxes out around 15 grams.

I just ordered a couple out of curiosity. I don't really need it with the M3 grinder. What is your favorite basket Barry?

[barry]

What is your favorite basket Barry?

for hand dosing/tamping: the stock LM cinch-waist double;
for use with the swift: the LM straight-sided triple.

[HB]

If I dose 15 grams, the grounds do not fill up the basket.

I dose to the best puck-to-head clearance, not a specific weight. But if you want a smaller basket, isn't the stock basket for your Giotto in the strict 14 gram ballpark? Below is a picture of it next to the ubiquitous 18 gram basket.


Giotto stock basket (left) and ubiquitous 18 gram basket (right)

For those looking for a really small double basket, check out this 12 gram basket that was accidentally shipped when I ordered 18 gram baskets:


18 and 12 gram basket

Now I'm curious... what's your interest in these small baskets? Maybe I need to start thinking about them; on a whim I switched to triple baskets over the weekend and noticed a huge dent in my coffee supply by Monday.

[malachi]

So you're trying to downdose.
Ah-hah.

I find the keys to downdosing are:

1) careful initial dosing (I rotate the portafilter under the doser) to get the best possible starting distribution,
2) very gentle handling of the portafilter,
3) applying increasing pressure while distributing (stockfleth's of course).

With point #3 above - the idea is to start by merely moving the "pile" in a rotational pattern to fill in any low spots and then gradually increasing downwards pressure the create best distribution.

All this being said - I find downdosing in the stock LM basket somewhere between difficult and impossible due to the ridge.
I have a shallower Cimbali basket I sometimes use for some coffees, but the basket I most often downdose in is the triple basket.

[Abe Carmeli]

I dose to the best puck-to-head clearance, not a specific weight. But if you want a smaller basket, isn't the stock basket for your Giotto in the strict 14 gram ballpark? Below is a picture of it next to the ubiquitous 18 gram basket.

Perhaps I need to make this a little more clear. The Giotto double is for a 14 grams dosage. However, if you dose exactly 14 grams pre leveling, the coffee grounds do not fill the basket. They come below the basket rim and that brought up the question: How do you properly level & distribute 14-15 grams of dosed coffee? Both Schomer & Stockfleth require that pre-leveling the grounds will at least be at the level of the basket rim.

Now I'm curious... what's your interest in these small baskets? Maybe I need to start thinking about them; on a whim I switched to triple baskets over the weekend and noticed a huge dent in my coffee supply by Monday.

Most of my ristrettos are 15 grams shots. But I must say that I do not have a personal interest in the matter. The M3 grinder allows me to dose 14-15 grams and do proper leveling/distribution with even density, as I mentioned earlier. My interest here is for the majority of people who use standard grinders. As to triples, I rarely use them. I drink mostly ristrettos, and do not find a need to use 22 grams of coffee to get a rich and thick cup. 15-16 grams is enough in most cases.

[malachi]

I doubt most people dose by weight - but rather by volume.

Also, keep in mind that on most grinders you trap between 1 and 4 grams of coffee (the Versalab being an exception).

Personally, I've only found one coffee ever that (IMHO) tasted best with a 14 gram dose (in a LM basket). Just my taste perhaps.

[Abe Carmeli]

I doubt most people dose by weight - but rather by volume.

I think you are putting too much emphasis on the weight here. Forget about the grams. The question is can you properly distribute a less than a full basket. I guess your answer is no.

[malachi]

No, actually, that is untrue.

If you look back through the thread you'll note that I gave some instructions for how to downdose in a larger basket.

If you handle your dosing correctly and then handle your distribution correctly, it's not a problem.

Wait... I'll be right back with notes on how low I can go in a ridged basket before I run into distribution troubles just to make sure.

[HB]

Wait... I'll be right back with notes on how low I can go...

Another HB first! Realtime down-dosing! (*sorry* )

[malachi]

OK.

First - a clarification or two...

1) Just because most people dose by volume doesn't mean it is impossible to dose by weight, just that dosing by volume is more reliable, predictable and easier.

2) While it is possible to downdose in a LM ridged double basket, it's not easy.

15 grams isn't hard at all.
14 grams is a serious challenge.
Below 14 grams requires a 57mm tamper.
Dosing below 15 grams with any degree of consistency is VERY hard.

And...
here is the simple way to dose light (or down dose) with a standard grinder and a LM ridged double basket:

1) grind coarse, tamp hard.
2) stockfleths' for distribution.
3) dose more than the target to give yourself some room to play with (you'll brush the remainder off).
4) use a 57mm tamper.
5) make sure you rotate the portafilter (slowly and gently) while dosing.
6) flick the doser fast.
7) distribute initially without pressure at all - just fill in gaps.
8) try to apply as little pressure at all when distributing - even at the finish.


final note - i think you might be getting fooled when comparing grinders. are you weighing your dose after you've dosed and distributed? if you're dosing by weight, that's the weight that matters.