I'd love a factual scientific explanation on this.
I know from experience that vacuum marinating does work and works faster than without vacuum. You can marinate meat like steak in minutes as apposed to hours and hours otherwise.
But why does this work? I haven't read an convincing explanation. I know it does work....from experience...but why?
I'm thinking as such:
1) you are lowering the pressure outside of the meat. Of course
2) So...the internal pressure in any cavity inside any pores or spaces inside the meat will be greater that the outside...at least for a time until equalized.
4) So what ??? How does that help marinate the meat any faster?
Maybe since the marinade starts out below the meat at the bottom of the container...it is drawn up into the meat thru any pores or cavities via pressure differential.
This would require a pressure differential between the bottom of the container, where the fluid marinade is, and the atmosphere above the meat. So in effect you are drawing the liquid marinade from the bottom of the vacuum container through the meat to equalized the pressure differential. I can believe that...but is that what's actually happening?? I don't know for sure.
Opening or widening of any cavities is possible too. Put a marsh mellow in a food saver container and draw a vacuum and you can watch it expand. But this would only work with closed cell cavities. Pressure inside the cavities remains at one atmosphere but the outside becomes less that one atmosphere.
So why would that help draw a liquid into a piece of meat? I don't think it would. I also don't see a piece of steak expanding when I put it in a food saver container and draw a vacuum.
I think my first explanation makes the most sense.
When you draw a vacuum in the container it first develops above the meat.
Below is a pool of liquid marinade...an incompressible fluid.
The meat acts like a gasket or seal between the area below it, filled with fluid marinade, and the low pressure area above.
This imbalance isn't natural...and lower pressure region seaks to balance with the higher pressure region below....so the marinate fluid is drawn up and thru any pores or cavities in the meat, trying to fill the vacuum above...because nature abhors a vacuum.
Meat may or may not have pores. I don't thing it does....but it certainly does have gaps and spaces in it's mass.
So to be succinct and scientific...I suspect...you are just sucking the marinade thru the meat with a vacuum marinade system like a food saver container.
I will totally consider other theories.