another_jim wrote:Then dosing becomes a matter of diagnostics, that is, tasting the shot and deciding whether it needs more or less coffee.

Mostly, if the coffee taste flat, without much in distinct flavors, you should dose more. If the coffee tastes harsh and angular, with too many bitter and sours, you should dose less.

I'm wondering if it is presumed that the flow rate stays the same? Depending on how much the dose needs to be changed, might a change in grind be needed to maintain the same desired flow rate?

AndyS wrote:For some time, I too, have believed the same theory: solubles yield is more or less inversely proportional to dose. It stands to reason that low doses, more finely ground, would yield higher. But I'm having a great deal of difficulty proving the theory with actual measurements......

....With the 14g doses, maintaining about the same brew ratio, my measured solubles yield went DOWN 1.5% to 2%. To get back to the 18.5% solubles yield range, I had to pull "longer" shots (brew ratio ~54%, 26g of beverage). [see chart, below]

Some comments on this earlier part of the thread: Aside from prescriptions such as X oz pulled from Y g in Z sec, is there a definition of ristretto, normale, lungo, etc.? I've seen these discussed in various capacities and combinations of dose, % extraction and brew ratio....however, it seems a reference to the product of % extraction and brew ratio (= solubles concentration), as well as this quantity normalized to the dose (i.e. solubles concentration/dose) would be better.

For example, consider the discussion of the high brew ratio shots measured by AndyS earlier in this thread, the 18 g shots are slightly "stronger" than the 14 g shots with higher brew ratios (soluble concentrations approximately = 0.116 vs 0.105 respectively for these shot groups). But, the difference in solubles concentrations is only about 9% despite the 18g shots being pulled from about 25% more dose.

Another way to look at this is that the lower dose shots are actually yielding more solubles per g of dose per g of bev. I think this is the essence of "reason" behind the initial expectation that it "stands to reason that low doses, more finely ground, would yield higher"....they do indeed, per g of dose.

The point I am grappling with is that solubles concentration (i.e. g solubles per g of beverage) sets the scale for the "strength" of the shot (think ristretto, normale, lungo); while the manner in which you get that strength (i.e. from how large a dose - i.e. g solubles per g of beverage per g of dose) better describes the extraction "quality" of the shot. These two quantities seem like they would more clearly define and characterize one shot especially in comparison to another.

double_pedro wrote:I'm wondering if it is presumed that the flow rate stays the same? Depending on how much the dose needs to be changed, might a change in grind be needed to maintain the same desired flow rate?
[...]
[...] is there a definition of ristretto, normale, lungo, etc.?

Since you are using Italian caffè jargon, I would think you would stick to their definitions.
You can find definitions from the super-posters on these fora also.
Mind the date of such posts, however. I sense that the US overdosing, relative to Italian style, that used to be, nowadays is much more qualified as a different approach and some of the main characters here actually have dosed down towards the 14 grams per 2 normale. At least amongst the some of the aficionados here.

Generally speaking, I would say the answer to your flow rate observation is in the "time" variable.
Your extraction (including ristretto, normale and lungo) will be somewhere between 22 and 35 seconds.
I would keep a ristretto on the low side of the range and the normale in the middle.
Lungo is a different cup of coffee altogether, should still be in the range and not blonde, IMO.

In other words, yes, you have to adapt the grinder.

Regards
Peter

double_pedro wrote:The point I am grappling with is that solubles concentration (i.e. g solubles per g of beverage) sets the scale for the "strength" of the shot (think ristretto, normale, lungo); while the manner in which you get that strength (i.e. from how large a dose - i.e. g solubles per g of beverage per g of dose) better describes the extraction "quality" of the shot. These two quantities seem like they would more clearly define and characterize one shot especially in comparison to another.

Well put.

It sounds like maybe you are trying to see these espresso prep variations as analogous to recipes; that is a misunderstanding.

In practical terms, you control the dose, the grind setting, and how long you run the pump. All three have an influence on the taste. We have rules of thumb for picking all three, but there is no substitute to taking a single blend of coffee and trying it in various combinations of dose, shot time and volume. This will increase your shot making skills, your tasting skills, and attach some experience to the variations we are trying to describe.

The blend of coffee, along with the roast, is more analogous to the recipe. Changing the shot variables is like tasting a sauce after its finished cooking, and adding a pinch of this or that. That's important, in big kitchens, it's the job of the senior chefs, since it takes taste and experience; but it's not the sauce recipe.

Agreed! Good one, Jim . . .

CafSuperCharged wrote:Generally speaking, I would say the answer to your flow rate observation is in the "time" variable.
Your extraction (including ristretto, normale and lungo) will be somewhere between 22 and 35 seconds.
I would keep a ristretto on the low side of the range and the normale in the middle.
Lungo is a different cup of coffee altogether, should still be in the range and not blonde, IMO.

This suggestion contradicts the often quoted (but never substantiated) guideline known as Al's Rule, which states that you should pull the shot for a slightly longer time for ristrettos, and slightly shorter for lungos. The reasoning: the flow rate for ristrettos is slower, so each coffee particle "sees" less water in 25 seconds, hence you should extract longer to compensate. Al's Rule suggests that you lengthen ristretto pour times by 1 second for every 5ml below the "golden rule" volume of 50-60ml, so a 25-30ml ristretto should take about 30 seconds. Shot timings go in the opposite direction for lungos.

I don't (intentionally) pull many lungos, but they tend to be blonder than normales and ristrettos. This is to be expected, given the lower brew ratio of a lungo.

Well, I can see I am clearly out of my league here, but thank you for humoring me with your responses to my queries.

So here is my latest summary:

1) The DOSE can be thought of as an "optimal" amount of coffee for a particular filter basket all other things being equal. Adding more or less coffee / dose as required after tasting is UP or DOWN dosing.

2) Using a double filter basket no matter what amount of coffee to produce a 1oz / 30 second shot would be a "ristretto" (As normally that amount of coffee would have produced 2oz in same 30 seconds),

3) While using a single filter basket to produce a 1oz 30 second shot would be a "normal" shot.

4) Single basket more difficult to use commercially for a single shot as usually need a second grinder as grind for single basket likely to be different than for double basket and,

5) Single basket may be more difficult to produce consistent pull as small variations in coffee amount are relatively larger to smaller amount of dose compared to same variation in larger amount required for double filter basket.

6) There will be differences in solubles and flavour profile using coarser grind / more coffee vs finer grind and less coffee even if adjusted to produce same volume in same time, e.g. 1 oz in 30 seconds.

7) The proof is always in the pudding, i.e. while there are certain parameters to follow, there is not single "correct" combination; its a matter of personal taste.

We've got a keeper.

RapidCoffee wrote:This suggestion contradicts the often quoted (but never substantiated) guideline known as Al's Rule, which states that you should pull the shot for a slightly longer time for ristrettos, and slightly shorter for lungos.

Speaking of "Al's Rule", does it assume the same dose, tamp, basket, grind? More specifically, what is changed to in order to affect the desired change in volume and shot time (namely +/-1 sec for every -/+ 5 ml of volume from the "nominal" 30 ml in 30 sec)? Is it the grind? dose? either? both?

double_pedro wrote:Speaking of "Al's Rule", does it assume the same dose, tamp, basket, grind? More specifically, what is changed to in order to affect the desired change in volume and shot time (namely +/-1 sec for every -/+ 5 ml of volume from the "nominal" 30 ml in 30 sec)? Is it the grind? dose? either? both?

Following the links back to Al's alt.coffee post (from March 2000):

As to ristretto. This a different drink altogether. If your grinder is set for regular espresso, and you choose to stop the pour at 25ml, this is simply an underextracted espresso. You haven't hit the sweet spot yet.
The "restricted" part referred to as ristretto is not so much related to volume as it is to water flow through the coffee puck.
...
If you customarily drink 25ml (or 50ml doubles), your grinder should be adjusted accordingly.