Homemade juices tend to accumulate some dregs at the bottom of the bottle. When pouring out the juice, one always hopes that the sediment wouldn't follow.. but as air bubbles through the neck of the bottle, it stirs the liquid and lifts the solids from the bottom. My mother wished for a pipe that would let the air flow freely to avoid this.

Materials

I have lately been using a lot of brass parts for my projects. It's hard and durable, but is easy enough to shape using hand tools and Dremel. It also polishes very well. Consequently, I already had some suitable brass pipe and flat rod available.

A small problem is that some brass alloys have 1-5 percent lead in them. However, brief research on Google suggests that it should not be a problem even for cups or utensils made of brass. Therefore considering the very short contact with the juice, I think it is pretty safe to use brass here. On the plus side, copper alloys are antibacterial.

Construction

To properly convey the air, the end of the pipe inside the bottle needs to be high enough to be above the liquid surface. To achieve this, I bent the pipe slightly. I didn't have any proper pipe-bending equipment, but fortunately for such a small bend it didn't matter.

The handle is mounted so that it both keeps the pipe in place at the mouth of the bottle, and also orients it properly so that the pipe curves upwards. The handle is soldered to the pipe using lead-free solder.

For aesthetics, I polished the parts using Dremel, both before soldering to reach all the spots, and after it to finish it off. The end result is not quite mirror-like, but close to it.

End results

The pipe does reduce the amount of bubbling. However, it doesn't eliminate it completely due to a few problems. Firstly, when the bottle is completely full, the hydrostatic pressure of the liquid inside the neck stops air from entering the lower portion of the bottle. The neck has to be empty before the pipe starts working.

Secondly, a more subtle problem is that some liquid gets trapped inside the pipe when it is inserted to the bottle. It forms a block to the flow of air until the pipe is tilted enough for the liquid to flow out.