When you pour it out the bottom, the air equalizing pressure pushes against the flow and causes the oscillation of the pour. When you do it the other way, nothing is coming out of the top of the spout, so the air flows in and doesn't effect the pour at all.what is this black magic?
I have to wash out 24 bottles for each batch of mead I make, and the fastest way to pour those is to use the "vortex" method; it creates a low-pressure zone in the center for air to enter, while also allowing liquid to flow outward.When you pour it out the bottom, the air equalizing pressure pushes against the flow and causes the oscillation of the pour. When you do it the other way, nothing is coming out of the top of the spout, so the air flows in and doesn't effect the pour at all.