S-Methyl thioesters, exemplified by S-methyl ethanethioate (methyl thioacetate), are organosulfur compounds featuring a thioester functional group where the sulfur atom is bonded to a methyl group. These compounds occur naturally in various foods and contribute to savory, cheesy, or sulfurous aroma profiles in spices and fermented products. Chemically, they are formed via esterification of carboxylic acids with methanethiol. They exhibit moderate volatility, making them important in flavor chemistry. S-Methyl thioesters are generally stable under neutral conditions but can hydrolyze in strong acids or bases. Their presence in trace amounts enhances umami notes in culinary applications, and they are studied for their role in Maillard reaction byproducts and microbial metabolism in food science.