NOVELTY - Producing products from biomass comprises: fermenting biomass to produce a first product stream of carboxylic acid salts; acidifying at least one of the first stream and/or a second product stream to produce a third product stream comprising acids; extracting acids from the third stream with a solvent, and subsequently separating the solvent from acids to produce separated solvent and a fourth product stream comprising acids; processing the fourth stream to produce a fifth product stream; and recycling at least a portion of the fourth or fifth stream for use as at least part of the solvent.    USE - The process is useful for producing products including medium-chain fatty acids (4-11C, preferably 4-8C VFAs) from biomass (all claimed).    ADVANTAGE - The process: is simple and economical; provides the ability to remove the inert gases, which may result in savings in compression energy; provides for operating expenditure savings on dewatering, as a lot of the water does not need to be removed; avoids solids handling downstream of the fermentation; provides very high yields from the ketonization; has at least one reaction occur at lower temperatures; provides easy recovery of medium-chain fatty acids; and does not require undesired chemicals.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for producing medium-chain fatty acids from biomass comprising: fermenting biomass to produce a first product stream comprising short- and medium-chain fatty acid salts; acidifying at least one of the first product stream and/or a second product stream to produce a third product stream comprising acids; allowing the third product stream to phase separate into an organic phase and an aqueous phase; and recovering medium-chain fatty acids from the organic phase.    DESCRIPTION OF DRAWING(S) - The figure shows a process diagram that includes use of a fermentation system where biomass to be fermented into carboxylic acids salts or volatile fatty acid salts is fed to it and the salts are converted to acids using an electrochemical acidification unit.    Water (201)    Electrochemical acidification unit (202)    Fermentation system (203)    Undigested residue or digestate (204)    Fermentation broth (205)