NOVELTY - Producing biomass slurry comprises mixing biomass which has been subjected to steam explosion with an aqueous liquid in the presence of one or more hydrolyzing proteins under conditions that: (a) are unfavorable for enzymatic saccharification by one or more hydrolyzing proteins; and/or (b) result in less than 40%, less than 30%, less than 20% or less than 10% glucan (e.g. glucose and/or cellobiose) saccharification by one or more hydrolyzing proteins.    USE - The methods are useful for producing biomass slurry; and for continuous production of biomass slurry (all claimed). Generally, the methods are useful for pretreatment of biomass, for example to form biomass slurry suitable for downstream processing (e.g. saccharification, and fermentation).    ADVANTAGE - The methods provide advantages in industrial operations, such as better heat exchange, reduced power and water usage, and the ability to carry out reactions continuously due to the reduced requirement for cleaning reaction vessels.    DETAILED DESCRIPTION - Producing biomass slurry comprises mixing biomass which has been subjected to steam explosion with an aqueous liquid in the presence of one or more hydrolyzing proteins under conditions that: (a) are unfavorable for enzymatic saccharification by one or more hydrolyzing proteins; and/or (b) result in less than 40%, less than 30%, less than 20% or less than 10% glucan (e.g. glucose and/or cellobiose) saccharification by one or more hydrolyzing proteins; and/or (c) require at least 10%, at least 20%, at least 30%, or at least 40% less power to mix the biomass with the aqueous liquid as compared to mixing biomass and aqueous liquid in the absence of the hydrolyzing proteins over 2-, 5-, 10-, 15- or 20-minute period; and/or (d) permit mixing of a slurry containing at least 10%, at least 20%, at least 30%, or at least 40% more biomass solids without increasing power usage as compared to a slurry mixed in the absence of the hydrolyzing proteins, thus producing biomass slurry. An INDEPENDENT CLAIM is a method for continuous production of biomass slurry, comprising: (a) combining biomass which has been subjected to steam explosion, an aqueous liquid and one or more hydrolyzing proteins into a vessel comprising a biomass slurry, where the biomass, an aqueous liquid and one or more hydrolyzing proteins are introduced into the vessel at a rate in which the slurry viscosity in the vessel is maintained; and (b) simultaneously pumping slurry out of the vessel at a rate that maintains the slurry volume in the vessel; where the conditions in the vessel: (i) are unfavorable for enzymatic saccharification by one or more hydrolyzing proteins; and/or (ii) result in less than 40%, less than 30%, less than 20% or less than 10% glucan (e.g. glucose and/or cellobiose) saccharification by one or more hydrolyzing proteins; and/or (iii) require at least 10%, at least 20%, at least 30%, or at least 40% less power to mix the biomass with the aqueous liquid as compared to mixing biomass and aqueous liquid in the absence of the hydrolyzing proteins over the residence time of the biomass in the vessel; and/or (iv) permit mixing of a slurry containing at least 10%, at least 20%, at least 30%, or at least 40% more biomass solids without increasing power usage as compared to a slurry mixed in the absence of the hydrolyzing proteins, thus continuously producing biomass slurry.