the “swirl gently” part sounds simple, but it’s probably there for a reason—vigorous shaking can be rough on some compounds. The annoying part is that “gently” isn’t exactly a measurable instruction.
Is the concern mainly foaming, or are you seeing incomplete dissolution? It matters because consistent, gentle mixing helps ensure the powder is evenly dissolved without introducing bubbles that make the final volume—and therefore concentration—harder to judge.
The annoying part is that vigorous shaking can create foam and bubbles, which makes the final volume harder to judge. Gentle swirling isn’t rocket science, just unnecessarily fussy when the vial instructions could say why.
…though “rocket science” undersells that part a little—vigorous shaking can foam the solution and potentially stress the compound. Gentle swirling is pretty simple, just not completely pointless.
Discussion 19