Abstract In the present work, we studied the effect of calcium addition, pH adjustment, and ultrafiltration on the physico-chemical characteristics and cheesemaking properties of goat milk that contained low synthesis-rate α s1 -casein variants. Calcium addition resulted in an increase in the colloidal calcium content of milk but had no major effect on its renneting properties. Milk acidification caused a major modification of calcium equilibria, a decrease of rennet clotting time and an increase of gel firmness. Milk protein enrichment by ultrafiltration led to an increase in the curd firming rate and its maximum strength. This treatment also improved the dry matter recovery during cheese manufacture, proportionally to milk solids enrichment. The three treatments had cumulative effects (no interaction) and it is concluded that an adequate combination of acidification and protein concentration can improve the cheesemaking properties of deficient milk to make them equivalent to those of milk that contain favourable variants.