Chlorococcum sp., grape marc, and Pinus radiata have been reacted in a semi-continuous (flow through) system at 425 degrees C under a flow of N-2 or H-2 and results compared to those from batch autoclave experiments. This paper concentrates on the structure of the condensate, which is more useful and more amenable to analysis. Under similar reaction conditions, the flow through system gave lower yields of dichloromethane soluble materials plus water plus gas for Chlorococcum sp. than a batch autoclave, higher yields for P. radiata, and similar yields of the same fraction for grape marc. Two distinct condensate phases (organic and aqueous) were produced, the composition and amount of which depended on the biomass type and the gas atmosphere (N-2 or H-2). Constituents of the original biomass were often better preserved in the flow-through than in batch autoclave reactions under similar conditions. (C) 2015 Elsevier Ltd. All rights reserved.