sous vide vs. braising?
I've been cooking sous vide style for over a year, using a home-made water-immersion circulator (pid, PT-100 probe, relay, fish-tank pump, and 1200W heating element) dunked into a beer cooler.
I've noticed many a time the vacuum-sealed bags puff up a little and get filled with juices from the food - this was especially the case when I did a 10lb brisket for 48 hours.
How is that different from braising, other than environment temps?
Not sure exactly what you're asking.
The main difference is the cooking temperature. A piece of meat braised 3 hours in cooking liquid near boiling will have a very different effect than the same piece of meat cooked for 30+ hours below 150 f. Cooked sous vide, the meat's fibers will contract less, leading to less loss of juices and a significantly different texture.
There are other differences too. The cooking liquids (if you use any) don't reduce while cooking sous vide as they do in a braise. There is no maillard reaction taking place during sous vide, whereas there is sometimes but not always browning during a braise (beyond the initial sear). Volatile flavor compounds aren't lost while cooking sous vide as they are in a braise, leading to a slightly different flavor - sous vide achieves a kind of heightened intensity of the flavors of the main ingredient. You generally use far less liquid if any when cooking sous vide, allowing again for different flavors and effects.
And then of course, sous vide can be used in many ways that's not like braising at all - most shorter cooking times apply.