Analysis and experiment on pressure swing extraction of Fine Coffee Technology

We can now reflect different flavors from coffee from one place of origin through siphon, hand brewing, and even Italian style. As a barista, as long as you handle the baking degree, you can find a best fit point under different temperatures and pressures.

Or, we have an extraction method to try coffee from different places.

Or, the same Italian style, the same kind of coffee, under the premise that the extraction flow rate is basically the same, in the combination of different grinding degree, extraction time, and powder quantity adjustment, to find your own favorite flavor. Moreover, there is a great change in flavor.

So, if someone says that La Marzocco can get very different styles of coffee by arbitrarily adjusting from 1 to 12 atmospheric pressure during the extraction process, and introduce this revolutionary technology to the fourth wave, should we believe it?

Slayer is the first coffee machine with the concept of variable pressure.

La Marzocco Strada coffee machine with stepless regulation and variable voltage

Before writing this series, I thought about it for a long time, discussed it for a long time, and inquired about a lot of information, including Mark Prince's comments on "kicking the Pavilion" on New York Times (http://dinersjournal.blogs.nytimes.com/2010/02/10/what-kind-of-coffee-do-you-get-for-18000/)). But the experiment did not begin. Because, before doing the experiment, the first thing I want to know is several problems with a certain logical chain.

1. If all other conditions remain the same, whether the transformer can really bring about a change in flavor.

If there is little difference, there will be no so-called change.

two。 If there is a difference, is it possible for such a difference to promote a new field of coffee? That is, even if the flavor of all the coffee can not be changed better, whether it gives us more flavor choice.

If not, there will be no so-called change.

3. If so, can we think about changing the amount of powder or the degree of grinding, and regularly search for its style differences.

If so, it will certainly become the standard of the industry like the E61 heat exchange in 1961.

If not, it will be more difficult to say. Because, even if a few specific coffee beans can find a variety of styles by changing pressure, but there is no certain standardization, such popularity is more difficult.

At this point, some people may have doubts, because the relationship between powder quantity and grinding degree is not something that many coffee shops can grasp. However, the reality is that both Intelligentsa in the United States and several excellent roasting coffee shops in Australia already have relatively strict standards for the freshness, grindness and powder of their coffee beans. They will ask their employees, for specific beans, in a specific number of days, to have a relative amount of powder and extraction time. I even suspect that La Marzocco has accepted the suggestion of intelligentsa and has the function of storing all kinds of coffee flavor parameters on strada. Because before this, intelligentsa sent the extraction parameters of various flavor coffee beans to each coffee bean, and required strict compliance. (La Marzocco did consult coffee shops like intelligentsa,veneziano before developing all kinds of machines.)

If we sort out these three problems, in fact, we can roughly know whether the change in stress is a flash in the pan, an epoch-making initiative, or change, but only as a function of icing on the cake.

Here, I have to introduce the illustration diagram of strada as the benchmark of the experiment.

Figure 1 represents our usual standard extraction.

Figure 2, in order to reflect the flavor of coffee, we can first low pressure during the extraction period, and then slowly increase the pressure.

Figure 3, in order to improve the fullness of coffee, we can first increase the pressure of coffee to high pressure (9 atmospheric pressure or even 12 atmospheric pressure), and then gradually decrease until the end of extraction.

Figure 4, if we want to change the overall flavor, we can gradually increase the pressure and then gradually reduce the pressure.

Figure 5, how do you want to play?

Whether the picture is true or not, at least it gives us some inspiration.

1. Flavor can be obviously changed by pressure.

two。 It is regular to change the flavor by changing the pressure. The front low and the back high may increase the flavor or acidity, and the front high and the low may change the plumpness.

There is also a digression. Before strada came out, VST also specially cooperated with strada, using its newly developed uniform filter bowl as its standard. I don't know if there is a connection, but at least one lesson is that if we really want to do this experiment, we should set all other parameters as constant as possible. This includes keeping the water temperature as constant as possible, the amount of powder unchanged (the error is less than 0.2g), the degree of grinding unchanged, and of course the coffee beans must be the same in the same period. Moreover, in order to make the experiment as representative as possible, the flavor of coffee needs to be balanced as much as possible, rather than some unconventional settings in order to highlight a certain flavor.

Therefore, according to the existing hardware conditions, the experiment can be designed into this mode.

1. Use the pre-embedded function of the existing coffee maker (my coffee maker can set two modes of low pressure (3 atmospheres) and high pressure (9 atmospheres). Compare the flavors of the first three.

two。 Then compare the TDS (soluble concentration) of the three.

If there is a significant difference in flavor, then there must be a considerable difference in TDS. If the difference in style is not obvious, there is a difference in TDS. Then you can try to make other beans better and compare them again.

3. If conditions permit, try to repeat the above experiment on Strada. And compare whether the speed and general reference of changing pressure will have an impact on the results.

Here are a few points to note:

An experiment is blind. Tasters do not know what kind of pressure mode this extraction is.

B the degree of grinding shall be determined by the best flavor point of the first standard extraction. (this may bring limitations. Because of different pressures, different grinding degrees may be required.

C as mentioned earlier, the recipe for coffee beans must be relatively balanced. Therefore, mixed coffee beans, medium roasting, just before the second explosion, it is more appropriate.