Kefir is a fermented beverage obtained through lactic and alcoholic fermentation realized by an association of lactic bacteria and yeast in milk, sugary water or fruit juice. In this study, orange juice and milk were assessed as substrates in the fermentation by two types of kefir grains (culture for milk - MC and culture for sugary water- WC) by means of factorial design. The results obtained indicate that there was a greater growth of the WC than the MC, high yield in the production of beverages (~90 g/100g de substrate) and the concentration of substrates had a higher influence over SSf and pHf than the initial amount of kefir. The cellular growth of the MC was not affected by the quantity of kefir grains and there was no relation between growth and the production of CO2. The addition of 50%w/w of milk promoted greater fermentability and the augmentation of kefir grains increased the production of CO2 for the WC.