This research aims to study the optimal production quantity of each type of roasted coffee beans for the maximum profit using the simplex method and Big-M technique. A case study: DTC FOOD PRODUCTS company, under the brand SUCHADA, sources its coffee beans from Doi Langka, Thep Sadej Subdistrict, Doi Saket District, Chiang Mai, which has been granted a Geographical Indication (GI) certification. The roasted coffee beans products are categorized into three processing methods: Washed Process, Dry Process, and Honey Process. Each method includes three roasting levels: Light, Medium, and Dark, resulting in nine variations, along with Drip Coffee, making a total of ten product types. The study involves data collection, on-site surveys, modelling of linear programming problems and data analysis to determine the optimal production quantity. Calculations are performed using Microsoft Excel program to ensure accurate results.
             Upon conducting the operational analysis, it was determined that in the absence of a specified daily production requirement, the application of the Simplex method suggests that the optimal production strategy involves manufacturing either 343 bags per day of Light Roast Dry Process coffee beans or Light Roast Honey Process coffee beans, in addition to 205 bags per day of Medium Roast Drip Coffee. This production plan yields a maximum daily profit of 89,967.50 THB. Conversely, when daily production requirements are imposed and the Big-M Simplex technique is employed, the optimal production configuration comprises 338 bags per day of either Light Roast Dry Process or Light Roast Honey Process coffee beans, 1 bag per day of Medium Roast Washed Process coffee beans, 4 bags per day of Dark Roast Washed Process coffee beans, and 205 bags per day of Medium Roast Drip Coffee. This arrangement results in a maximum daily profit of 89,792.50 THB.