A properly designed study
Combined with the aforementioned perfected method for freezing/thawing. Most attempts won't be as successful but GF's may well be, I don't know. Earlier well-designed studies I've seen have been less neutral on the effects, too. FWIW I'm a scientist by training, so I do follow the evidence. Bottom line is it's possible to freeze freshly roasted beans and thaw and use them later with (subjectively) no perceivable effect, but why risk it (unless you're travelling to the arctic and can't take a roaster ). Hence I don't recommend it. But if there's no perceivable difference to the particular consumer, that's all that matters. We return you to your regular (style) programming.