The present disclosure relates to a method for controlling product slate of hydrothermal liquefaction by adjusting pH of hydrothermal liquefaction product aqueous phase. The pH of the hydrothermal liquefaction product aqueous phase can be adjusted by heating during hydrothermal liquefaction (110) a mix (30) comprising lignocellulosic feedstock (10) together with acids, alkalis and/or buffers (20) added under aqueous conditions. The method typically comprises separating (120) aqueous phase (53) and oil phase (50), and optionally gas (51) and/or char (52), of the obtained hydrothermal liquefaction product (40). Preferably the separated aqueous phase (53) is recirculated to be mixed 100 with lignocellulosic feedstock (10).