VST claims that its baskets are more consistent in commercial operation than regular baskets. The study does not support this claim. Random shot to shot variation is large enough that the differences in conventional baskets are only a minor exacerbating factor. Moreover, the narrower dosing range of the VST baskets means that it amplifies small random errors in grind and dose. In this study, this added error proneness offset any gain from tighter manufacturing tolerances.
The VST-18 and equivalent Strada basket have become popular among third wave professionals and serious amateurs. This section and the taste section suggest that more important for this acceptance than any consistency gain is that the 18 gram VST basket fills a niche in dose-to-grind relations, roughly a 2.5 shot, that was previously unoccupied. People wanting to make 18 gram shots would have to under-dose a triple or over-dose a double, with correspondingly extra fine or extra coarse grind settings.
The higher the dose, the punchier tasting the shot. This punch is a combination of astringent, cutting and bitter flavors that wine lovers get from tannic wines, and which they call “structure.” The higher the dose, the more structured the shot; the lower the dose, the creamier and softer tasting the shot. Since this effect disappears as the crema dissipates; this structure difference is clearly caused by differences in the crema of high and low dose shots.
Italians like soft and creamy espresso; but Seattle and West Coast espresso typically has a lot more punch. Five years ago, West Coast blends were medium roasts and had low acidity; and one could get away with overdosing a double basket and grinding coarse. With the advent of more acidic and brighter SOs and blends, the choice with a conventional double is to grind finer, dose lower, and give up the punch; or to make a very rough shot with coarser grinds and higher doses. The VST 18 gram baskets uses the same grind as a conventional double at 15 grams. This means it delivers the high dose structure without the unacceptably rough and sour taste of under-extracted, lightly roasted coffee. This may explain why some people strongly prefer the VST18 or Strada baskets.
Finally, the VST 22 and OEM triple are very similar in dose requirement, and I compared them to check whether claims that better finished baskets taste better, or at least different, was supportable. This pair of baskets delivered the punchiest shots. So much so that I found them unpleasant and hard to distinguish. Therefore, I was unable to judge whether the hot taste of these baskets differed.