This disclosure provides effective methods for expanding the processing window for poly(ethylene furanoate) (PEF) and poly(ethylene furanoate) co-polymer (PEF co-polymer) polyester preforms, such that these preforms can be beneficially used in the fabrication of bottles and containers, including bottles for carbonated soft drinks. The processing window is expanded by, for example, pre-conditioning the PEF or PEF co-polymer preform prior to stretch blow-molding by contacting the PEF or PEF co-polymer preform with water or high (>50%) relative humidity air for a desired time period and at a temperature greater than or equal to ambient temperature, to take advantage of the unique and unexpected properties afforded the preform by water sorption at these temperatures.