[Modernist Cuisine] Kalbi Flank Steak (3•199)

[Anonymous Modernist 6826]

My friend and I endeavoured to replicate this recipe with some rather unpleasant results. We deviated slightly, so I thought it would be best to ask for some advice on this forum.

Mirin proved to be very difficult to locate so we substituted sake in its place. As the recipe suggested, we marinated for 5 days, but froze it thereafter as our conflicting schedules didn't allow us to attend to it on time. We then cooked it at the recommended 54C for about 2 hours. We found that the flank steak (sourced from our local butcher) was both difficult to brown and very unpleasantly chewy. To remedy this problem, we put it back in the water bath for another 12 hours at 55C (as recommended in 3-109). This yielded in a better steak, but it was still very chewy and unyielding. We could clearly see where the collagen sheaths dissolved but the meat had an oddly stiff texture. I noticed that I got a similar effect with marinated salmon vs. regular salmon. The marinade caused the fish to be unpleasantly chewy and I was forced to overcook it until it was edible. I'm wondering if the marinade is similarly responsible for the outcome of the flank steak. Is it possible that substituting sake caused this?