An airless baby bottle includes: a) an elongated shaft having an open top and an open bottom and having a constant internal cross-section, and having attachment means for securing a nipple piece fastening collar thereto b) a nipple piece fastening collar c) a nipple piece having a main body with an outer rim and having a nipple with at least one liquid-release orifice and nipple having a plurality of accordion segments so as to create a rest short nipple position and so as to permit a stressed elongated nipple position when a baby sucks on it d) a piston to sealably and moveably fit within the elongated shaft, the piston having external sides with a peripheral upper blade and a peripheral lower blade, each of said peripheral upper blade peripheral lower blade having a plurality of peripheral ridges running perpendicular to the elongated shaft elongation direction.
