A cap apparatus includes a cap body and a valve body. The valve body includes an upper portion, a lower portion, and a stem intermediately disposed between the upper portion and the lower portion, the valve body including a bore formed therein having concentric alignment to and traversing the upper portion and the stem, and the valve body including a perforation formed therein having concentric alignment to and traversing the stem and the lower portion. The perforation forms a substantially impermeable seal within the valve body. The cap body includes an aperture in coaxial alignment with the bore and the perforation. The inner surface of the cap body includes multiple internal threads.