Trying to improve extraction with a new high end machine - some pointers please!

[Bames]

Agreed Vinitasse. You keep telling is over and over again that VSTs are crap, refractometer a are useless, and 'espresso' is only 'xyz' and anything outside that is wrong. But I wouldn't call you a tool, at least not to your face.

[Vinitasse]

Seems to me that there are quite a few tools trying to tell us what is good and what isn't

[ASchecter]

So, is it possible to pick a good shot if you don't have a tool to tell you it is?

Nope, not possible. It doesn't matter if a shot tastes great, the only thing that matters is the refractometer reading.

[timdimdom]

finally found some time to listen to ben kaminsky's lecture on espresso: https://www.youtube.com/watch?v=a-YI50dUC7g

He may not be the best presenter, but It's really worth a listen if you're looking to find reasons behind this 'benchmark' and the inherent flaws in the 'rules' It gave me a very good point to start on re: how much liquid we should aim to extract from a weighed dose. Some of the stuff there is, of course, way beyond my abilities and means, but it demonstrated the reasons behind what i am extracting from the coffee.

I believe open-mindedness is what brought us to third wave coffee in the first place which has allowed us to explore more of the endless possibilities in coffee.

So, is it possible to pick a good shot if you don't have a tool to tell you it is?

I feel like this is a 'why reinvent the wheel' kind of issue. and the short answer is 'because we can'
Yes it ultimately still boils down to taste, and i agree we shouldn't get too carried away with chasing numbers, but I think the numbers make us able to explain the differences in taste, and what other possibilities there are and how we can progress instead of sticking to the same ol thing and stagnating. Just because something is good doesn't mean it can't get better. 'good' may possibly be not as good as what you can achieve with the beans and machinery at your disposal.

[MrJack]

Read here for more information on that particular point.

Also, it's not clear what is meant by the yield "plateaus after ~20 seconds." When I've measured this, the yield continues to increase as total shot mass increases, but the yield of course increases by smaller and smaller amounts. Approximately 30% yield is considered the absolute limit of extractability.

That would be consistent with my expectations.

Considering the mass of solubles in the puck, rather than yield (which is the inverse), it is perhaps more obvious:

The different compounds in the coffee extract at different rates. Ones which extract quickly will deplete more quickly (possibly completely depleted at some point during the pour) and thus extraction rate will progressively decline.

Plotted as a yield curve, this would look like a relatively sharp increase in yield, slowing over time, and tending towards maximim yield.

Mass transfer kinetics in action

[TC]

So, is it possible to pick a good shot if you don't have a tool to tell you it is?

[Vinitasse]

I have no desire to reprise the endless debate over objective measurement vs subjective taste. Obviously a great-tasting shot is the goal we all strive for.

That said, both my VST refractometer and my "palate refractometer" tell me that it all depends on the shot parameters. I have pulled dozens of shots (and I'm sure you have, too) that ran well past 20-25 seconds and PLENTY of value was still being extracted. This is typical for ristretto shots, which often require extra time to achieve flavor balance.

Creating a "rule" that extraction "should end" or "does end" at 20 seconds is hopelessly narrow-minded.

Then again, there is the other side of the coin as well... where one is SO open minded that their mind remains closed to anything that isn't new and/or different. Seems to be more than a bit of that going on here

[Vinitasse]

...hopelessly narrow-minded.

That would be an awesome name for a funky new cafe

[ASchecter]

My palate refractometer informs that little of value is extracted after a pour time of 20-25 sec. You need only split a shot to work this out.

I have no desire to reprise the endless debate over objective measurement vs subjective taste. Obviously a great-tasting shot is the goal we all strive for.

That said, both my VST refractometer and my "palate refractometer" tell me that it all depends on the shot parameters. I have pulled dozens of shots (and I'm sure you have, too) that ran well past 20-25 seconds and PLENTY of value was still being extracted. This is typical for ristretto shots, which often require extra time to achieve flavor balance.

Creating a "rule" that extraction "should end" or "does end" at 20 seconds is hopelessly narrow-minded.

[TC]

My palate refractometer informs that little of value is extracted after a pour time of 20-25 sec. You need only split a shot to work this out.

[ASchecter]

there is a flag above that exact section of the wikipedia article, indicating that someone has disputed it's factual accuracy

Read here for more information on that particular point.

Also, it's not clear what is meant by the yield "plateaus after ~20 seconds." When I've measured this, the yield continues to increase as total shot mass increases, but the yield of course increases by smaller and smaller amounts. Approximately 30% yield is considered the absolute limit of extractability.

[MrJack]

From Coffee extraction - Wikipedia, the free encyclopedia
Espresso yield features a number of surprising properties:^[5]

• yield depends primarily on depth of the "puck" (cylinder of coffee grounds);
• yield is inverse to puck depth;
• yield does not depend significantly on brewing time – yield at first increases approximately linearly, then plateaus after approximately 20 seconds;
• strength is independent of dose.

I'm not sure if you noticed, but there is a flag above that exact section of the wikipedia article, indicating that someone has disputed it's factual accuracy

I suspect that someone has, in the very least, done a poor job of summarisation.

[muppet_man67]

LM and VST worked together on the VST baskets. I'm 99% sure it is a VST, just branded LM. Even with your 1g scale, try grinding finer and just putting 17g in and see how you go.

yep they are the same, or similar enough. slightly smaller then 18gm vst and I don't think you can get hem in ridgeless.

[Bames]

LM and VST worked together on the VST baskets. I'm 99% sure it is a VST, just branded LM. Even with your 1g scale, try grinding finer and just putting 17g in and see how you go.

[Leonardo]

It is not a VST basket - has LM 17g stamped on it. I still don't have a scale graduated in 0.1g but it seem to be consitently 2 grams over. I have been filling the basket, levelling it with my finger and then tamping. Setting the machine to deliver 60mls and adjusting the grind to get complete extraction in 25-30 seconds produces great espresso.

When I can measure out 17 grams, will see what difference it makes - thanks Bames!


From Coffee extraction - Wikipedia, the free encyclopedia
Espresso yield features a number of surprising properties:^[5]

• yield depends primarily on depth of the "puck" (cylinder of coffee grounds);
• yield is inverse to puck depth;
• yield does not depend significantly on brewing time – yield at first increases approximately linearly, then plateaus after approximately 20 seconds;
• strength is independent of dose.

Strength depends instead on grind: finer grinds yield a "shorter" (ristretto) espresso (less liquid, so higher brew ratio, at same yield gives more strength), while coarser grinds yield a "longer" (lungo) espresso, while an intermediate grind yields a "normale" espresso.