[luc_h]

I think we all agree with the OP that plain water and herbs are not the way to go.

I assume that the steak in question is a though cut whereas marinating will tenderize it somewhat like for a flank steak or Bavette.

I dry rub a tender steak and marinate though cuts with a weak brine (with flavouring including an acid).

To tenderize, you need water to penetrate the muscle fibres tubules or disrupt the meat fibers. That can be accomplished in 3 ways:

using salt via a brine by soaking, injection or vacuum assisted which dissolves proteins in the muscle tubules so that water can penetrate deep in the tissue,

using mechanical means i.e. massaging, pounding, tumbling, penetrating with needles or blades

using phosphates which makes water more slippery and fill the tubules more easily (I know, I know not an option!!)

or a combination of any and all of the above.

For the home cook making a flavoured salt brine injecting with a hypodermic needle and add some massaging is achievable.

Luc H.

 

[luc_h]

... massaging, pounding, penetrating, makes more slippery, ...

out of context this sentence can invigorate other cravings(!?).

Luc H.

 

[luc_h]

In the last few years I have been adding a small amount of Papain to my marinade . It shortens the marinade time, penetrates the meat and makes it very tender. For years they have been doing this at Outback steak houses.

True that papain and other enzymes like ficin, bromalein and other proteases are effective meat tenderizers.

http://www.enzymedevelopment.com/html/applications/protein.html

My mistake for not mentioning previously. The techniques that I did mention above do not require to declare the term meat tenderizer on a label. Industrial meat processors try to avoid that term on labels, as a trained technical food reference in the industry, I tend to forget that option

thanks Ed.

Luc H.