Organic compounds produced by fermentation such as ethyl alcohol, or butyl alcohol and acetone, are removed by vaporization during the fermentation with the aid of a body forming an azeotropic mixture therewith, and, if desired, a gas may be passed through the liquor, but when the fermentation is anaerobic this gas should be free from oxygen. Suitable added liquids are hexane in the case of ethyl alcohol, and cyclohexane in the case of butyl alcohol and acetone. The liquid may be added continuously or intermittently and may be added in the form of vapour carried by the gas stream. Suitable additions of starting materials, ferments, or bacteria may be made to maintain the composition of the liquor constant. When using a top yeast, the enzyme effecting the change may be added, whereas with a bottom yeast it is preferred to add a co-enzyme. When producing alcohols, soluble phosphates may be added, preferably together with a body such as sodium arsenate, which prolongs the increased activity due to the addition of phosphate. When more than one product of fermentation is being produced, it is not necessary that the products should be removed in the same proportion in which they are produced. In an example, a solution of sugar, which may be produced from cellulose, is sterilized in a closed vessel, and a suitable yeast culture and suitable nutrients are added. The temperature is maintained at about 25 DEG C., hexane is introduced, and the pressure is reduced sufficiently to cause gentle boiling. During the process a sugar solution is added so as to maintain the concentration of the sugar constant, and other additions may be made.ALSO:Organic compounds produced by fermentation such as ethyl alcohol, or butyl alcohol and acetone, are removed by vaporization during the fermentation with the aid of a body forming an azeotropic mixture therewith, and, if desired, a gas may be passed through the liquor, but when the fermentation is anaerobic this gas should be free from oxygen. Suitable added liquids are hexane in the case of ethyl alcohol, and cyclohexane in the case of butyl alcohol and acetone. The liquid may be added continuously or intermittently and may be added in the form of vapour carried by the gas stream. Suitable additions of starting materials, ferments, or bacteria may be made to maintain the composition of the liquor constant. When using a top yeast, the enzyme effecting the change may be added, whereas with a bottom yeast it is preferred to add a co-enzyme. When producing alcohols soluble phosphates may be added, preferably together with a body such as sodium arsenate, which prolongs the increased activity due to the addition of phosphate. When more than one product of fermentation is being produced it is not necessary that the products should be removed in the same proportion in which they are produced. In an example, a solution of sugar, which may be produced from cellulose, is sterilized in a closed vessel, and a suitable yeast culture and suitable nutrients are added. The temperature is maintained at about 25 DEG C., hexane is introduced and the pressure is reduced sufficiently to cause gentle boiling. During the process a sugar solution is added so as to maintain the concentration of the sugar constant, and other additions may be made.ALSO:Organic compounds produced by fermentation, such as ethyl alcohol, or butyl alcohol and acetone, are removed by vaporization during the fermentation with the aid of a body forming an azeotropic mixture therewith, and, if desired, a gas may be passed through the liquor, but when the fermentation is anaerobic this gas should be free from oxygen. Suitable added liquids are hexane in the case of ethyl alcohol, and cyclohexane in the case of butyl alcohol and acetone. The liquid may be added continuously or intermittently, and may be added in the form of vapour carried by the gas stream. Suitable additions of starting materials, ferments, or bacteria may be made to maintain the composition of the liquor constant. When using a top yeast, the enzyme effecting the change may be added, whereas with a bottom yeast it is preferred to add a co-enzyme. When producing alcohols soluble phosphates may be added, preferably together with a body such as sodium arsenate, which prolongs the increased activity due to the addition of phosphate. When more than one product of fermentation is being produced it is not necessary that the products should be removed in the same proportion in which they are produced. In an example, a solution of sugar, which may be produced from cellulose, is sterilized in a closed vessel, and a suitable yeast culture and suitable nutrients are added. The temperature is maintained at about 25 DEG C., hexane is introduced and the pressure is reduced sufficiently to cause gentle boiling. During the process a sugar solution is added so as to maintain the concentration of the sugar constant, and other additions may be made.