When degassing your wine with a vacuum pump you need to use a glass carboy that is topped off When using a vacuum pump you want to have the vacuum all the way off when starting and slowly move it up to around 10" and then let it run for a few minutes. If you notice at any time the wine or foam approaching the bung or carboy cap you are using then immediately back off on the vacuum to let the foam go down and then slowly increase again. Once you can get it up to around 18-20" and hold it there without an eruption your wine is degassed. You should also notice that when starting to degas your wine the bubbles are very small and abundant but towards the end the bubbles are less frequent and much bigger, this is a visual tell tale that you are or almost done. Also, when done degassing always either shut your pump down and let all pressure out before trying to remove the bung or just turn the knob down all the way and wait until the gauge reads 0.