Streptococcus thermophilus strains St-143 and DGCC7785 are known to produce exopolysaccharides (EPS), where sugars in the repeating units are linked mainly by β (1→ 4), and β (1→ 3) types of gylcosidic linkages, respectively. We investigated the impact of addition of these isolated EPS to milk before fermentation on the properties of milk gels. Milk samples were fermented (at a similar rate of acidification) by these strains and these EPS solutions were isolated by ultrafiltration. Skim milk was rehydrated in these isolated EPS solutions containing 60, 120 and 200 mg of EPS/L, heated to 85°C for 30 min, cooled, and fermented at 40°C by a non-EPS producing S. thermophilus strain ST-1UWM until pH 4.6. Milk gels formed without any EPS, and formed by the respective EPS producing S. thermophilus strains were used as 2 types of controls. Rheological properties of the gels during fermentation were determined using small-strain dynamic oscillatory measurements. Yield stress and yield strain of the gels were determined at pH 4.6. Whey separation and permeability of the milk gels were measured at pH 4.6. The fermentation times for all the milk samples were similar (~250 min). The pH of gelation of the milk samples ranged from pH 5.1- 5.3. The storage modulus (G′) values at pH 4.6 of the gels made with in situ production of the β (1→ 3) linked EPS (72 Pa), and the in situ β (1→ 4) linked EPS (35 Pa) were significantly different from the control (non-EPS producer) (53 Pa). Addition of isolated EPS to milk did modify the rheological, whey separation and permeability properties, however, additional of isolated EPS could not exactly replicate the properties of the gels where this type of EPS was produced in situ. Other possible factors like the time during fermentation when EPS was produced, or the distribution of EPS within the gel network could play a role in explaining why isolated EPS could not better replicate the physical properties of acid milk gels.