The sharp-eyed internet users already discovered, that many professional chefs who use the sous vide, after he / she put the vacuum bags into the water, he / she shedding lot of ping pong balls to the water also. But why are they doing it?
Fact, that the meat flavour not will be better, and not used that balls to spice the meal! :)
The reason is so simple! When you heating long time the water, it evaporate. The ping - pong balls help to reduce this evaporation.
They can reduce the water's surface contact with air, which start the evaporation. But if the evaporation already started, the temperature of the balls surface above the water is much lower than the bellowed part, so the water wapour immediately condense and trickle back into the water.
Thats, why the chefs put ping - pong balls in the sous vide bath!