NOVELTY - Biomass pretreatment method (M1) involves introducing a biomass to a chamber; exposing the biomass in the chamber to a shock event to produce a shocked biomass; and transferring the shocked biomass from the chamber.    USE - For treating biomass comprising grain-based or lignin-based biomass (claimed) including lignocellulose and starch-containing grains.    ADVANTAGE - The use of a shock on biomass (including lignocellulose and starch-containing grains) enhances the digestibility of the biomass. The combination of shock treatment with alkaline pretreatment is performed under specific operating conditions, thus it is especially beneficial when the combination of shock treatment with alkaline pretreatment includes as the source of alkali a combustor ash. The apparatus provides rapid loading and unloading of biomass slurry; and allows for the use of inexpensive fuels (e.g. methane, hydrogen). The process has low cost, rapid processing, the ability to shock any particle size, and improved enzymatic yields. The shock treatment reduces the amount of enzyme required to achieve a target lignocellulose digestion; enhances the digestibility of lime-treated biomass in a rumen environment. The process reduces cycle and process time with an ability to quickly load and unload a shock vessel.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) enhancing (M2) biomass digestibility using shock treatment involving pretreating a lignin-based biomass with a chemical to produce a pretreated biomass; introducing the pretreated biomass to a high-pressure vessel; exposing the biomass to a shock event to produce a shocked biomass; and transferring the shocked biomass from the high-pressure vessel; and    (2) shock apparatus configured for rapid transfer of biomass to and from it comprising: a main body containing a chamber, first end, and second end, where the chamber is configured for the biomass transferred in it to be subjected to a shock; a first end cap movably associated with the first end, and a second end cap movably associated with the second end; a frame for holding the main body in a predetermined orientation; a first actuator coupled with the frame, where the first actuator is configured for opening and closing the first end cap; and a first clamp coupled with the frame, where the first clamp is operable to hold the first end cap in a sealingly engaged position with the first end.