"Definitely don't apply any sort of vacuum to plastic carboys! Even
glass might be dicey but plastic will just collapse and there goes
your wine... running on the floor..."

Hey, you don't go crazy with pumping! You pump only so much that the
wine level goes up close to the bung and then you stop pumping. After
a while, the wine level will go down as CO2 has been released and has
taken the place of the wine. You then stir the wine and use the pump
again or pump and shake the carboy.

I have been using a vaccum pump for many years on a few hundred kits.
In fact, I have many carboys with vaccum rather than airspace and
airlock. Every other day I pump more CO2 out and then lock the
vaccum. I don't care about a change in temperature or pressure, my
wine is not affected as I keep 2 in. of vaccum/CO2 below the bung.

Try it and you will like it as they say.

Guy