Top 5 Grinders for Light Roast Espresso Application - Page 7

Grinders are one of the keys to exceptional espresso. Discuss them here.

#61: Post by lagoon » Feb 10, 2019, 2:51 am

Nick Name wrote:Measuring things can give us good guidelines, but the final test has to be taste.

I don't know, but I think some time a go home baristas were more eager to arrange blind testing over just about anything you can think of. Today many people just talk about what a refractometer has to say about the coffee. I think refractometer can be a great tool, but let's not forget it's only a tool that is reflecting certain things. It is a fab thing at the moment, but who knows which will be the next fab thing...
These are excellent observations. Ultimately coffee is a sensory thing. For the human senses.

Due to over-reliance on scales and instruments, there's people coming into the hobby now that have none of the fundamental sensory skills such as being able to spot a blinding point, taste and smell the output to understand what's going on, observe the nature of the flow and so on.

As you say, top chefs refine their creations by taste, sight and smell.

In regard to the blind tasting sessions you mentioned, another issue these days, and probably exacerbated by webforums, is the phenomenon of "received knowledge" that drives threads like this.

To give an example, some guy somewhere on a board says grinder XY43KZ is the best thing in the world for light roasts. Another guy reads that and repeats it, and soon enough it becomes received-wisdom, despite a complete lack of empirical evidence.

Like you, I'd rather see more blind tests as the judge.
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#62: Post by malling » Feb 10, 2019, 5:17 am

nuketopia wrote:Again, this is the basis for double-blind testing. To eliminate biases and statistical variances. The same approach is used in color sciences, because of the variable of perception vs. measurement.

Holding all parameters but the burr type the same, we can test whether the burr type can be identified.

The panels have to include variable assortments to include sets containing all one type or the other, as well as mixed lots.

My hypothesis is that is impossible, and at most, we may see some very experienced tasters able to separate between two grinders. That's my hypothesis.

If we get into all sorts of other variables, then we're no longer identifying burr types, we're identifying entire preparation chains.

No one has yet indicated a coffee which can only be prepared properly as espresso using a flat burrs grinder.
Obviously if you decide for a panal that include allot of untrained tasters or tasters who has little experience with said grinders, they would not be able to taste any difference, as they would not have the experience to do so, they might notice a difference but they'll at best just be guessing.

Why you usually use cupping, it is the only method that is reliable enough, espresso as a method will never be reliable enough for blind testing, there is simply to much varience in extraction when serving larger quantities that would be required.

Putting pp or fp into the mix you could just as well be testing for the effect of profiling, so you'll have to use a "flat" classic 9 bar profile.

Yes you'll need 3 sets one for each burrset and a mixed, where the latter is composed of two identical and one from the other burr type.


#63: Post by bakafish » Feb 10, 2019, 5:23 am

Is it true that a SSP flat burr grinder can easily reach 25%-26% extraction yield of an espresso shot of light roasts? What are the parameters such as beans weight, pressure profile and brew ratio?

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#64: Post by Denis » Feb 10, 2019, 5:32 am ... ing-yield/

You cannot hit with any coffee. And remember a more even grind= more EY.


#65: Post by bakafish » replying to Denis » Feb 10, 2019, 5:55 am

Of course I know that, but my question is "Is it (25-26% espresso extraction yield for very light roasts mentioned in some previous articles of this thread) true on a SSP flat burr grinder and what are the parameters?", not the theory.

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#66: Post by Denis » Feb 10, 2019, 6:27 am

There is no fix recipe, because the coffee you are using is not the same (solubility wise).

Here is an example of high EY:

20g fine grind, heavy WDT (with a special tool not a needle or a whisk), OCD, light tamp.

Slow PI (25-30 sec), slow ramp from low to high P (8-9bar), keep it there for as long as the coffee allows you to, then go down finishing the extraction at 5-6 bar.

20 g in, 60 g out in 65-70-75 sec (30 sec slow ramp up PI, 20-25 sec 9 bar, 10-15 sec ramp between PI and 9bar and drop from 9 bar to 5-6 bar). But you have to look at the naked PF and the pressure in order to know when to make the ramp/drops. One recipe doesn't apply to all coffee. For example if you have medium espresso roasted coffee you might find this taste disturbing. If the coffee is a normal roast/espresso then you might find a better taste in a shorter shot (ratio and time wise) and you might grind coarser for this.

As for the people doing blooming shots, this is just a sneaky cheating to fool the grinder drawback you are having. You will not be able to do 30 sec PI with a bimodal grind because of the uneven particle distribution. Think about any brew method you want, if you have more even particles you have more extraction, because water saturates the grind more efficient then you extract even from everything.
After saturating the coffee puck with water from blooming, you change its internal structure, it similar to a sponge, it doesn't offer you enough hydraulic resistance to stand up for the high flow brew at 9 bar for a long period.

In my head there are 2 types of extractions:
-long preinfusion but you have to be carefully because you can easily choke or compress the coffee and that leads to channeling, because water will find a weak spot to break through. If you are to aggressive with the flow on the PI stage its most likely you will end up under extracting. This type of shot allows you to be more aggressive on the brew and lets you put more water at high pressure than the blooming shot.

Long preinfusion is this: a 18g coffee puck takes aprox 27 g of water to saturate (i did meassure it more times), this means you need to put ~ 1g/sec for a 30 sec preinfusion.

- short preinfusion - followed by a big bloom period- this has the advantage that you fill the coffee puck faster with water and therefore you will have a more even extraction theoretically. This method is good but the following brew at high pressure for a big ratio of 1:3 will just melt down your puck integrity and the puck will erode a lot faster, not allowing you to extract more (higher EY, higher ratio). A solution to the bloom shot would be to try to extract more than time and ratio at a lower pressure (6 bar). This is validated by the fact that if you do a bloom shot then you need to grind finer than a normal high PI shot.

There are machines out there that have real time feedback so a big force is taken away from the coffee puck if it starts to lose integrity. An example would be either the La Marzocco Leva or the Speedster Idro-matic. It is easier to have higher EY on these type of machines. In order to close, all I can say is that there is a big difference in taste between a long PI long brew high P shot and a short PI-bloom shot-.


#67: Post by bakafish » Feb 10, 2019, 11:42 am

Denis wrote:You will not be able to do 30 sec PI with a bimodal grind because of the uneven particle distribution.
I don't think so because my big conicals can do the Slayer style shot. I don't like 1:3 brew ratio especially for light roasts so I never had a chance to measure the EY at this brew ratio. Now it looks interesting to have some tests with your method for my big conicals and 804 LAB SWEET. Thank you.


#68: Post by ds » Feb 10, 2019, 12:27 pm

bakafish wrote:Of course I know that, but my question is "Is it (25-26% espresso extraction yield for very light roasts mentioned in some previous articles of this thread) true on a SSP flat burr grinder and what are the parameters?", not the theory.
I think its a pipe dream... Also, I have not seen any blind taste studies that show that actually high extraction yields are tasting better. In my mind its all about balance and not so much about EY. Which is why people are pulling 3:1 ratios, they are trying to balance out that battery acid extraction to make it palatable.

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#69: Post by Denis » Feb 10, 2019, 12:40 pm

:mrgreen: exactly!!!!

We bought really expensive coffee and equipment to pull battery acid shots.


#70: Post by ds » replying to Denis » Feb 10, 2019, 12:49 pm

There's no accounting for taste... But you are welcomed to show us a blind taste study which shows high extraction yield espresso tastes better...