A polyester container having an enhanced level of crystallinity in the sidewall while maintaining a low level of crystallinity in a thickened base portion. The container is particularly useful as a refillable container which can withstand higher caustic wash temperatures and exhibits reduced flavor carryover, or as a hot-fill container. The container, which can be monolayer or multilayer, is also useful as a carbonated beverage, O2 or CO2 barrier, or beer container.