NOVELTY - Method to recover a 3-6C alcohol (I) from a fermentation broth comprising microorganisms and (I), comprises: (a) increasing the activity of (I) in a portion of the fermentation broth to at least that of saturation of (I) in the portion; (b) forming a 3-6C alcohol-rich liquid phase and a water-rich liquid phase from the portion of the fermentation broth; and (c) separating the 3-6C alcohol-rich phase from the water-rich phase.    USE - The methods are useful to produce and recover a 3-6C alcohol (propanol, butanol, iso-butanol, pentanol or hexanol) from a fermentation broth. The method is useful to recover higher alcohols from dilute aqueous solutions (fermentation broths) (all claimed).    ADVANTAGE - (I) output of the retrofit plant is at least 80 (preferably at least 95)% of (I) equivalent of the ethanol maximum output of the plant before retrofit. The enrichment of alcohol from the dilute aqueous solution to the condensed vapor is at least 5 (preferably at least 15) fold. The method provides improved volumetric productivity for the fermentation and allows recovery of the alcohol. The method reduces the energy utilization in the production and drying of spent fermentation broth due to increased effective concentration of the alcohol product by the simultaneous fermentation and recovery process, which increases the quantity of alcohol produced and recovered per quantity of fermentation broth dried. The method allows for production and recovery of (I) at low capital and reduced operating costs.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a method to produce (I) comprising: either (a1) culturing a microorganism in a fermentation medium to produce (I); (a2) increasing the activity of (I) in a portion of the fermentation medium to at least that of saturation of (I) in the fermentation medium; (a3) forming a 3-6C alcohol-rich liquid phase and a water-rich phase from the portion of the fermentation medium; (a4) separating the 3-6C alcohol-rich phase from the water-rich phase; and (a5) conducting the water-rich phase to the fermentation medium in the first step; or (b1) hydrolyzing a feedstock comprising a polysaccharide and at least one other compound to produce fermentable hydrolysis products; (b2) fermenting at least a portion of the fermentable hydrolysis products in a fermentation medium to produce (I), where the fermentation medium further comprises at least one non-fermented compound; (b3) increasing the activity of (I) from a portion of the fermentation medium to at least that of saturation of (I) in the fermentation medium; (b4) forming a 3-6C alcohol-rich liquid phase and a water-rich phase from the portion of the fermentation medium; (b5) separating the 3-6C alcohol-rich phase from the water-rich phase; and (b6) separating the at least one non-fermented compound from the fermentation medium, the water-rich phase or both; or (c1) distilling a vapor phase comprising water and (I) from the fermentation broth; and (c2) reacting (I) in the vapor phase to form the product; or (d1) culturing a microorganism in a fermentation medium to produce (I); (d2) increasing the activity of (I) in a portion of the fermentation medium; (d3) distilling the portion of the fermentation medium to produce a vapor phase comprising water and (I) and a liquid phase; and (d4) conducting the liquid phase to the fermentation medium;    (2) a method to operate a retrofit ethanol production plant comprising a pretreatment unit, multiple fermentation units, and a beer still to produce (I), comprising: pretreating a feedstock to form fermentable sugars in the pretreatment unit; culturing a microorganism in a fermentation medium comprising the fermentable sugars in a first fermentation unit to produce (I); treating a portion of the fermentation medium comprising (I) to remove a portion of (I); returning the treated portion of the fermentation medium to the first fermentation unit; and transferring the fermentation medium from the first fermentation unit to the beer still; and    (3) a method for extraction of (I) from an aqueous solution, comprising contacting the aqueous solution with an acidic, amine-based alcohol-selective extractant.    DESCRIPTION OF DRAWING(S) - The figure shows the production and recovery of iso-butanol.    Fermentor (10)    Heat exchanger (20)    Flash tank (30)    Vapor condenser (40)    Phase separator. (50)