I’m not familiar with these egg bites, but I am familiar with sous vide in general.
The phrase means “under vacuum” in French, and is the term used for a specific cooking method where the food is vacuum sealed, then cooked in a precisely calibrated water bath. Which doesn’t sound like much, I’ll admit.
The vacuum sealing part isn’t the important part, other than keeping the water off the food itself and transmitting heat efficiently. What IS important is the ability of the water bath to reach and maintain an exact temperature, as this is how the food’s actually getting cooked.
Let’s use a steak as an example. Plenty of research has been done about how beef cooks, and at what temperatures and times the various events happen as it cooks. So let’s say we want to cook our steak to a nice medium. We’ll arbitrarily say that “medium” equals 140 degrees (there’s a lot of disagreement out there actually). So if we were to cook it using the normal methods- broiler, grill, hot pan, we’ll end up with an outside that’s nicely seared, and the inside at 140. But everything in between will be somewhere between probably 300 and 140, giving us a sort of doneness gradient from outside to inside, and with most of the steak being somewhere above 140. It’s just a consequence of using a fast, high-heat method.
But let’s say we use the sous vide cooker to cook that steak. We can set our water bath to 140, vacuum seal the steak, and plunk it in the water. Since that water’s being kept at 140 and no higher, the entire thing will be cooked to 140, and be “medium” all the way through. From there, we can take it and dry it off, oil it up and sear it in a hot pan/put it over a hot grill/use a blowtorch/under a broiler and get a good sear on the outside. This takes a LOT less time than cooking it, so while we still end up with that doneness gradient, it’s much smaller- like 1/8" or less.
For other dishes where temperature is even more critical and seared outsides aren’t important like fish and eggs, sous vide is even more impressive.
As for equipment, basic steak making doesn’t take anything other than a picnic cooler, Ziploc bags and an accurate thermometer. You just heat the water a little above your desired temp, and let it come to an equilibrium, which ends up cooking your steak.
If you want to do other stuff, you’ll need some sort of circulator/temp controller. There are several consumer-grade ones on the market these days- Anova, Joule, Sansaire, Nomiku, PolyScience and others. They run between about $100-250, depending on which one and what sales are available. I have an Anova one, and it’s great. The only downside is that you sort of have to remember you have it, or else you’ll go off and cook things the old way without thinking about it.