I skipped to the last line.This is why science is so fun, and why I prefer the experimental sciences to theoretical science! I’d like to preface this by stating that I’m not a food scientist, and there are people here who know more than I do. But my good friend is a food scientist, so I can find a definitive answer to the aged meat question for you. Sometimes, there are variables that I haven’t thought about, because my degrees are in different scientific fields. In addition, thermodynamics is very complex, and molecular hydration shell entropy will forever haunt me! Without boring everyone with long equations that mean very little to most people, and comparing each variable for a bunch of molecular compounds, I’ll try to keep this brief, and give the Cliff Notes version.
1. There is a difference between thermodiffusion involving solids, liquids (the Soret coefficient), and gases. Probably the least understood are liquids (see the aforementioned hydration shell entropy). Gases and aerosol particles (like smoke) can have different barriers to diffusion into another substance, depending on the following:
a. The polarity and ionization potential of the molecules involved. Polar molecules and ionic compounds (salt, etc.) are only dissolved in polar liquids, such as water. Nonpolar molecules are only dissolved in nonpolar liquids, such as oil/fat. Polar aprotic solvents are a different beast, but I’m going to skip them, because you shouldn’t have much of those in your food .
b. The presence or absence of a liquid will change the way that substances diffuse, as mentioned above. Diffusion is more difficult through a solid substance due to decreased particle motion and the space between molecules. This partially explains the difference between a polyester/rayon/nylon/ etc. couch, and a liquid-rich substance, such as meat.
c. The molecule itself. Totally unrelated to temperature, some molecules aren’t “structurally bonded,” so they ionize and diffuse easier. Others have extremely strong covalent bonds and behave differently. Size of the molecule also affects the ability to diffuse, especially if a cell membrane is involved (something living things have- more on that later). The molecular elements and structure itself will give each substance different characteristics of density, elasticity, and plasticity, and different molecules will behave differently when exposed to various temperatures. All of that can change how molecules diffuse through that substance. One of the hardest things for me to get used to in my advanced inorganic chemistry courses was the unpredictability of various elements and molecules, because there weren’t a lot of reliable patterns (at least not to me, but I don’t have a PhD in chemical engineering ).
d. There are a lot of other variables of the elements in each specific molecule, including thermal conductivity, specific heat capacity, electronegativity, etc.
e. Lastly (at least for now, off the top of my exhausted brain), meat is a formerly living thing. It’s not just a compound substance, but a variety of substances with complex organization, such as cellular membranes, intercellular and extracellular fluids, pores, and a bunch of other things. Molecules will move through each of these structures differently, AND dead tissues behave differently than living tissues.
All of this is why I’d rather just perform an experiment instead of work off of theory!
All right, now that I’ve thoroughly bored the living daylights out of everyone here, I think the biggest difference in your aged meat could be hydration. Less hydration would mean less attraction of smoke molecules, and would change the diffusion of those molecules into the meat. Secondly, if there is any fat or oil on the surface, that will result in less attraction and diffusion. Most seasonings contain ionic compounds and polar molecules that should play well with the polar smoke molecules.
Again, there are people here who know far more than I do. I’ll also try to get in touch with my friend for a more definitive answer on aged meat .
Who wants ice cream?