Abstract: A method for preparing a fermented beverage with low alcohol content, in particular a wine with low alcohol content, involves only biological methods for fermenting natural fruit juice. The method includes essentially the following steps: a) feeding an aerobic culture reactor containing yeasts in multiplication phase with a first fraction of fruit juice; b) feeding an anaerobic fermentation reactor with a medium loaded with yeast obtained at step a) and with a second fraction of fruit juice, to obtain a must; c) filtering the must to separate the yeast and the resulting fermented beverage. In accordance with one important feature, the relative volumes of the first and second fractions of fruit juice are proportional to the desired final degree of alcohol and final proportion of sugar of the fermented beverage. Also described is a device for preparing such a beverage.