NOVELTY - Refining a sugar stream, comprises: either heating activated carbon to 100-300 degrees C to produce heat activated carbon and contacting the sugar stream with the heat activated carbon to produce a refined sugar stream. The heat activated carbon is at a temperature greater than the sugar stream; or acidifying the sugar stream to a pH of 1-4 by adding an acid to produce an acidified sugar stream and contacting the acidified sugar stream with activated carbon to produce a refined sugar stream.    USE - The process is useful for refining a sugar stream.    ADVANTAGE - The process utilizes activated carbon, which: adsorbs less than 20%, preferably less than 10% of the sugars in the sugar stream during contacting; removes 70% or more, preferably 80% or more of at least one of the inhibitors from the sugar stream comprising at least one inhibitor comprising furfural and/or hydroxymethylfurfural; increases the transparency of the sugar stream by 50% or more, preferably 75% or more, when contacting with the sugar stream, where the transparency is measured at 600 nm; and removes 30% or more, preferably 70% or more of at least one of aromatic or phenolic compound from sugar stream comprising at least one aromatic or phenolic compound. The process provides refined sugar stream with concentration of total sugars of 5-60%, preferably 15-40% (all claimed). The process minimizes the loss of sugars and sugar polymers in concentrated sugar streams derived from pretreatment of cellulosic and lignocellulosic materials, while decolorizing the sugar stream and reducing the concentration of inhibitors.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) producing a refined sugar stream, comprising pretreating or hydrolyzing a biomass comprising cellulosic, hemicellulosic or lignocellulosic material to produce a sugar stream, where the sugar stream has a total sugar concentration of 15% or greater and contacting the sugar stream with activated carbon to produce the refined sugar stream;    (2) refining-1 a sugar stream, comprising heating activated carbon to produce heat activated carbon, storing the heat activated carbon in a non-oxidizing environment and contacting the sugar stream with the heat activated carbon to produce a refined sugar stream; and    (3) the refined sugar stream produced by the process as above per se, comprising concentration of total sugars that is at least 15 wt/vol.%, concentration of at least one inhibitor that is at least 70% less than an originator sugar stream, concentration of at least one aromatic phenolic compound that is at least 30% less than the originator sugar stream or transparency that is at least 50% higher than the originator sugar stream, where the refined sugar stream was contacted with activated carbon.