An optimization approach for the lot sizing and scheduling problem in the brewery industry

• A mixed integer program for the production scheduling in breweries is proposed.
• The optimization model integrates the fermentation/maturation and bottling stages.
• Processing time for liquid preparation in the production stages lasts several days.
• MIP-based heuristics exploring the model structure data are presented.
• Computations experiments based on real data are performed and analyzed.

This study considers a production lot sizing and scheduling problem in the brewery industry. The underlying manufacturing process can be basically divided into two main production stages: preparing the liquids including fermentation and maturation inside the fermentation tanks; and bottling the liquids on the filling lines, making products of different liquids and sizes. This problem differs from other problems in beverage industries due to the relatively long lead times required for the fermentation and maturation processes and because the “ready” liquid can remain in the tanks for some time before being bottled. The main planning challenge is to synchronize the two stages (considering the possibility of a “ready” liquid staying in the tank until bottling), as the production bottlenecks may alternate between these stages during the planning horizon. This study presents a novel mixed integer programming model that represents the problem appropriately and integrates both stages. In order to solve real-world problem instances, MIP-based heuristics are developed, which explore the model structure. The results show that the model is able to comprise the problem requirements and the heuristics produce relatively good-quality solutions.