Overdosing leads to inconsistent results

[nixter]

I just found a problem with my technique and hopefully solved it. I've been over dosing. I have a grinta grinder which I fill while spreading the grounds around with a knife. I then level things off carefully and tamp hard for ristrettos. I've been getting inconsistent results with this however, finding it very hard to duplicate the taste from shot to shot. I pulled out my scale and decided to measure a dose by weight instead of volume for once. I dosed 14g in a small cup and then dumped that in my double basket. Bingo! The 14g untamped were well below the rim of the basket! I guess something to do with the doserless Grinta was creating major overdosing in the basket. I should have guessed by the frequent screw impressions in my pucks, duh! anyways, i pulled the naked 14g shot and it looked and tasted beautiful.

yay

n

[RapidCoffee]

Someone's channeling Ken Fox...

[nixter]

Someone's channeling Ken Fox...

Ha, just finished reading that thread. Interesting. I discovered this on my own but I'm glad to see others have found the same thing.

[malachi]

the problem wasn't overdosing.
it was inconsistent dosing.

[HB]

I pulled out my scale and decided to measure a dose by weight instead of volume for once. I dosed 14g in a small cup and then dumped that in my double basket. Bingo! The 14g untamped were well below the rim of the basket!

the problem wasn't overdosing.
it was inconsistent dosing.

Chris may be right... your volume dosing can vary considerably unless you practice. One of the exercises for tuning your barista techniques:

Volumetric coffee dosing - for a long time I was into weighing beans either before or after grinding to confirm the dosage. Sometimes when I'm first testing a machine the old habit will return, but generally I'm a basket volume guy. If I'm overstocked with beans, that's one place they'll be put to use: Dose, weigh, dose, weigh (repeat five times). My target accuracy is within 0.5 grams and I won't get too irritable if it remains within 0.7 grams.

I wrote that over 2-1/2 years ago and I still bounce back-n-forth between volume/weight dosing. For example, it's a complete waste of time for the Ponte Vecchio Lusso where a level cut is 12 grams every time. My accuracy is less reliable when downdosing, so I will frequently spot check the weight.

[nixter]

My volume dosing was bang on in terms of consistency. I used to weigh after volume dosing. The problem in this case was definitely overdosing. I believe the answer lies somewhere in the height of the water buffer between the puck and the screen. A kind of preinfusion, but not.

n

[malachi]

I've been getting inconsistent results with this however, finding it very hard to duplicate the taste from shot to shot.

Inconsistency in the taste of the shot is highly unlikely to be related to using "too much" coffee.
Inconsistency pretty much results from inconsistency if you know what I mean.

[HB]

Inconsistency in the taste of the shot is highly unlikely to be related to using "too much" coffee.

True, but some espresso machines are more finicky about updosing than others.

For example, the Elektra groups will ruthlessly punish baristas with a penchant for updosing. The E61 group tolerates updosing, but is more forgiving with normal dosing. I've noticed that groups with uneven water dispersion and/or very little room behind the dispersion screen for "dwell time" water to collect are more demanding about the precision of the dose. Even the number of holes in the diffusion block can make a difference. For example, Bob Barraza's Livia 90 was noticeably more forgiving once he closed the original 6 holes and redrilled 10 evenly spaced ones.

[malachi]

Absolutely!
But that "punishment" rarely (if ever) takes the forms of inconsistent results in the cup - right? Bad results, sure.

[HB]

Sorry, I use "bad results" and "inconsistent results" synonymously...

To restate, for a number of espresso machines I've used, updosing reduces the barista's margin of error. For example, if the grind is slightly off, tamp is canted, or distribution is uneven, the in-cup results will vary more dramatically than with a normal dose. By lowing the dose, Nikolai has increased his margin of error and thus reduced the shot-to-shot inconsistency.

[nixter]

Nikolai has increased his margin of error and thus reduced the shot-to-shot inconsistency.

I think I'm actually REDUCING my margin of error.