Serious Eats has this to say on the topic of salting steaks:
“Seasoning a steak prior to vacuum-sealing it, then letting it rest in the bag, can result in meat with a firm texture, similar to that of a mildly cured ham. Some folks find this texture off-putting, though I personally don't mind it. To avoid this texture, it's best to season and bag a steak immediately before cooking, or after cooking sous vide and before searing.”
And Chef Steps has this to say:
”You may have heard talk about holding off on adding salt to your food toward the beginning of the cooking process, and it’s true that over time, salt will interact with proteins to alter a meat’s texture. This is a function of time—the longer the meat and salt interact, the more the texture will be altered. In the case of sous vide steak, we ran tests to see whether salting impacted the texture in any discernibly negative way. It didn’t! So go on and season that stuff before you cook. It’s all gonna work out great.”
