Inoculation of L. buchneri (LB) is well recognized for extending aerobic stability of silage during feed out. The effect is mainly documented by measuring temperature change during small scale aerobic challenge. The objective of the current study was to investigate the microbial and chemical changes occurring during re-exposure of air to mini-silos inoculated with or without L. buchneri (LB). Newly harvested maize was collected from a farm in Denmark in September 2013. The maize was inoculated with tap water or LB and vacuum packed in 1-kg bags and stored at 25°C for 2, 7 or 15 weeks (n = 5 per treatment). For the aerobic challenge, the silage was divided into 2 containers (1.2 L; 274 kg/m³) with a 1 cm hole in the top and bottom, and kept at room temperature for 156 h. After aerobic challenge for 0, 3 and 7 d chemical and microbial analysis were performed on all samples. Data were statistically analyzed as a randomized complete block by using GLM procedure by SAS. The none-fermented maize was highly contaminated with yeast and mold of log 6 and log 5, respectively. Aerobic stability and number of yeast was not significantly (P > 0.05) improved by inoculating with LB after 2 weeks, but LB inoculation improved the aerobic stability and reduced number of yeast significantly (P < 0.05) compared with control, when the silage was kept anaerobic for 7 or 15 weeks. During the aerobic challenge both the microbial and chemical composition changed. Yeast enumeration significantly (P < 0.05) increased during the aerobic challenge, except for the LB inoculated silage after 15 weeks of anaerobic fermentation, where yeast count was lower than detection level (log 2). Acetate, ethyl acetate, lactate, and ethanol levels decreased significantly (P < 0.05) during aerobic challenge for both treatments and anaerobic fermentation time points. Considerable chemical changes occur during aerobic challenge and with increased anaerobe fermentation the effect on aerobic stability by inoculation with LB improves.