That's right. Even those casting their minds back to school who didn't do Physics exams*, should have been taught that you can't compress a liquid. But the void about it will have a pressure great enough to stop the liquid CO2 boiling (think pressure cooker), which will be fixed at a specific temperature (about 860psi at room temperature). (* That includes me! But school is a very long time ago any way. I just didn't like having these "bombs" about the house and have no understanding of them. Mixed gas is completely different; it does not form a liquid at a reasonable temperature/pressure and so is sold as a compressed gas at 2-3000psi). Guess we won't get questions off you concerning refilling Sodastream cylinders from Pub bottles!