This is from one of the episodes of Conan O'Brien's show. In this video he takes one of his staff members to a coffee roasting house. There is a short technobabble at one point in the video:
https://youtu.be/fVDOB9mby_w?t=430
The context starts at 7 min 10 sec (linked above), but the actual statements this question is about, starts at round 7 min 26 sec (https://youtu.be/fVDOB9mby_w?t=446)
Is she describing an actual procedure, or is it just nonsense that sounds real and technical?
The barista was describing the physical action of extraction rather than a specific procedure. The coffee-making procedures are designed to produce the right amount of extraction.
The living coffee beans contain cells of plant material within a cellulose structure. When the beans are roasted, the water is driven out and the heat cooks the beans. You get a "woody" cellulose nugget with all the different organic compounds still integrated and trapped within it.
Roughly 30% of the coffee bean is stuff that is soluable to one degree or another. Stuff that is highly soluble goes into solution first during the brewing process. The less soluble the compound is, the longer it takes to go into solution. The compounds fall into general categories, like acids, sugars, fats, etc. Compounds in the different categories tend to have similar solubility and generally similar kinds of flavors.
So early in the extraction, good-flavored acids go into solution (think of the acids in fruit) and predominate the flavors being extracted. Then sugars predominate the flavors being extracted, etc. As the extraction progresses, you get more of the flavors that make up the taste profile of coffee, and the flavor becomes fuller and more complex.
But if you continue to extract beyond the point where good flavors predominate, you start extracting more noticeable amounts of compounds that don't taste good (generally bitter and sour, but not in a good way). The barista mentions tannins, which are bitter and extracted later in the process because they're less soluble than some of the other compounds. An Intuitive Guide To Coffee Solubles, Extraction And TDS has a good description of all this.
So the idea is not to extract every last bit of soluable material, only the compounds that add pleasant flavors (roughly 20% of what's in the bean).
Getting the compounds into solution is affected by how finely the beans are ground (the finer the grind, the less time it takes the water to soak into the woody material to dissolve the soluble stuff), the water temperature (the hotter the water, the faster compounds go into solution; lower brewing temperature stretches the extraction time to more easily control the stopping point), brewing time, and some other variables, like agitation and pressure.
There are many different methods to brew coffee, from espresso, where the extraction happens in roughly half a minute, to cold brew, where extraction takes a major fraction of a day. But within any method, the flavor profile builds in the same sequence. The art and science of coffee making focuses on controlling the variables to get the good flavors extracted, and then to stop the extraction before the flavor is overwhelmed by bad flavors.
That's what the barista was describing.
