Fagus sylvatica wood samples were treated in HCl-catalyzed, acetic acid solutions. The effects of selected operational variables (catalyst concentration, reaction time and liquor to wood ratio) on pulp yield, composition of pulps and composition of pulping liquors were assessed using incomplete, second-order, centred, factorial designs. Pulp composition was measured by the contents in cellulose, xylan and lignin. The concentrations of glucose, xylose and furfural in pulping liquors were also considered as experimental variables. Under selected conditions, pulps with 5.8% to 7.5% Klason lignin (kappa numbers in the range 25 to 33), 77.2% to 85.3% cellulose and 3.3% to 6.1% xylan were obtained at 45.8% to 50.0% pulp yield. The selected pulps showed good SCAN viscosity (723 to 814 mL/g) and alkaline resistances which were affected by the acetyl group content of samples (6.6 to 7.6 weight percent).