One of the main by product obtained during beer production in the brewing industry is brewer’s spent grains (BSG). They are rich in cellulose, hemicellulose, lignin, and proteins. The aim of the work is to explore the effect of acid and alkali pre-treatments on BSG by studying the solubilisation behaviour of the organic molecules. BSG is chemically pre-treated using (alkali addition using NaOH, acid addition- HCl) by varying the concentration. After the pre-treatments, analyses such as pH measurements, total sugars using refractometer, reducing sugars using 3,5-Dinitrosalicylic acid (DNS) Miller’s method, total polyphenols using Folin–Ciocalteu method, proteins using Lowry method are carried out on the liquid phase. The results obtained could provide better insights into efficient chemical pre-treatment studies of BSG and further valorisation.