Digested softened non-defibrated chips are fed out from a bottom of a digester. The chips are fed out under an influence of a bottom scraper at the bottom of the digester and through an outlet tap at the bottom of the digester and onwards to an outlet line connected to the outlet tap. This takes place before the softened chips pass through a blow-valve arranged in the outlet line, across which blow-valve a pressure drop of at least 0.5 bar and at most 3-5 bar has been established. The chips are exposed to a displacement wash after the chips have passed the outlet tap. The displacement wash has been established in the flow of chips through the outlet line before the chips are defibrated by the pressure drop across the blow-valve.