This disclosure provides new methods, compositions, containers, preforms, and designs for refillable carbonated soft drink bottles having improved caustic stress cracking resistance. The method of this disclosure combine the use of PET-based co-polyester resin that incorporates a cyclic hydrocarbon diacid co-monomer and/or a cyclic hydrocarbon diol comonomer, with a bottle design incorporating a petaloid base, for unexpectedly enhanced performance.