Multi-layer fins for plastic zipper bags

A reclosable plastic bag comprises first and second opposing body panels, a zipper, a slider, and first and second upstanding panels. The opposing body panels are fixedly connected to each other along a pair of sides and a bottom bridging the pair of sides. The zipper extends along a mouth formed opposite the bottom. The zipper includes a first track with a first profile and a second track with a second profile. The first and second profiles are releasably engageable to each other. The slider is slidably mounted to the zipper for movement between a closed position and an open position. The first and second profiles are engaged to each other while the slider is in the closed position, and the first and second profiles are disengaged from each other in response to movement of the slider from the closed position to the open position. The first and second upstanding panels extend upwardly from the respective first and second body panels. Each of the upstanding panels includes opposing ends, and the opposing ends of the first upstanding panel are connected to the respective opposing ends of the second upstanding panel to form an open pocket in which the slider and zipper are captured. The open pocket may be sealed by joining the first and second upstanding panels to each other above the slider so as to completely encapsulate the slider within the pocket.