I once worked in a steak house. The chef would cut his own steaks, rub them down with a mixture of salt, pepper and garlic, wrap them, let them sit in the fridge for a couple hours, and then put them in pineapple juice for at least 24 hours (refrigerated). When I first saw this, I thought the pineapple juice would add an undesired sweetness to it, but when I tasted the result, it turned out not to be the case. A medium-rare filet minon prepared in this manner was tender enough to cut with a fork.
I can only imagine what this would do to a cut of Kobe or Wagyu!
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