Espresso concept-the Sweet Point Formula of Alti's Rule

In March of 2000, Mark Prince, who was still very young at the time, posted a newspaper tidbit, discussing the standard definition of Italian espresso, Mark's experience in Italy, and finally someone quoted a chapter from Schomer's book, and the topic suddenly turned to the term ristretto... Just when everyone began to be a little confused and suspicious, Al Critzer (formerly illy USA, Cimbali) joins the discussion string by providing a generalisation that has been extensively tested by the industry and commenting on ristretto. This info was passed on to me by Dr. illy and his disciples, so I guess it is an Italian way of thinking as well as the single most respected scientific mind in the field of espresso. He may be just a good person to spread information, but it is definitely a classic big event in the Internet forum at that time. He told a bunch of people who were passionate about coffee but lacked the right theoretical basis, a catchy formula. The few paragraphs he said, after years of tempering, not only the most common espresso concept in Europe and America, but even almost all the extracted documents that can be seen on the Internet are based on this, known as: Al s Rule,"Al Tie: Sweet Point Formula."

The original text reads as follows:

It seems that everyone's close, but pretty much all around it. As I was trained, the perfect espresso is 30ml in 30sec. That's assuming that all other factors are in line. For longer extractions, the contact time of water to coffee would have to be lessened so that undesirable elements associated with overextraction wouldn't be present in the cup. With shorter extractions, the water to coffee contact time would have to be increased to ensure that underextraction doesn't occur. This is accomplished by grind adjustment. A good rule of thumb I have developed is this: For every 5ml of espresso above 30ml, subtract 1 sec of extract time. By this formula 1 1/2oz (45ml) would require 27sec extraction, 2oz (60ml) would require 24sec, etc. The same holds true in reverse. This will find the sweet spot in espresso regardless of volume in the cup (within reasonable limits of .75oz to 2.5oz), as you are optimizing extraction to the desirable elements, maintaining the balance between under- and overextraction. For some reason, grinder adjustment and it's crucial impact on espresso is the most difficult concept to explain and grasp in all the trainings I do.

the effect that

Start with the result of getting a perfect cup of Espresso at 30cc/ 30sec. These two values depend on the beans, of course, and differences in baking methods, baking degrees, and recipe proportions naturally lead to changes in the reference point.

The amount of extraction is inversely proportional to the extraction time:

When the extraction amount is higher, the coffee powder must be in contact with hot water for a shorter time (avoid over-extraction).

Conversely, when the amount of extraction is reduced, the contact time between coffee powder and water should be increased (to avoid under-extraction).

Al formula: For every 5cc increase in extraction volume, the extraction time is subtracted by 1sec. Otherwise, add 1sec.

For example, when the extraction amount is increased to 45cc, 30-(45-30) divided by 5=27, the extraction time is reduced to 27sec.

When the extraction amount is 60cc, the extraction time becomes 24sec.

This formula, within reasonable limits of 0.75-2.5oz Espresso, quickly and correctly hunts sweet spots, effectively captures desirable ingredients, and maintains a terrible balance between over-extraction and under-extraction. The main method of control is to adjust the grinding thickness.

As for the controversial definition of ristretto in that era, Al Critzer also gave his explanation in passing:

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. The ristretto that has been used for cuppings is a 25ml cup in 30-35sec. This extraction intensifies the organoleptic perceptions of the eyes, nose, taste buds and upper pallate to better isolate the positive attributes of a given blend. Where the positives are accentuated, the negatives are exacerbated as well. The extractions are characterized by a very thin mouse's tail with rich, dark brown crema. Most people don't drink this as their everyday drink, but it is helpful in developing blends. If you customarily drink 25ml (or 50ml doubles), your grinder should be adjusted accordingly. Damn, I did it again….

Ristretto is a very different drink from normal espresso.

If grinding is not changed, use normal espresso flow rate, end extraction early, for example, at the original 30sec/ 30cc flow rate, only take 25cc, this is a cup of insufficient extraction results, because it has not reached the sweet point.

The so-called ristretto means restricted. The customary practice is 25cc/ 30-35sec.

All sensory sensations, whether good or bad, are accentuated: what the eye sees, what the nose smells, what the tongue tastes.

Tristretto is characterized by a mouse tail that is extremely thin, with a darker brown crema.

Most people don't drink this stuff every day, but it's good for the blend that's still developing.

If you're the type of person who drinks ristretto, whether it's 25cc or 50cc, then your grind needs to be adjusted accordingly. How to adjust? It's the same, Al Rule. Let's start over.

Al Critzer was in a discussion with Dr. Joseph John(Josuma Coffee Company) has another classic dialogue:

Dr John,

you didn't mention if this was done with the single filter or double. I'm hoping it was with the single. I personally am of the opinion that any espresso (single) should not be less than 25ml. A 1/2 oz (15ml) espresso has proved impossible for me to make in any drinkable state.

Here Al is equal to is reiterated his formula is at the beginning of the setting work, using the single basket brewing data as the basis for the calculation. That is, even if your store usually uses double filters, single filters are still the benchmark. In his personal experience, no espresso should be less than 25cc. A glass of 15cc espresso for him, is not able to reach the state of "drinkable"(the word drinkable is still far from good), which is equivalent to some people who like 30cc double ristretto in advance advice.