Phenol-formaldehyde resin having low concentration of tetradimer

A method of making a phenol-formaldehyde resin suitable for use in preparing a binder composition where a molar excess of formaldehyde (F) is reacted with a phenol component (P), the method comprising reacting formaldehyde (F) with the phenol component (P) under an alkaline condition in the presence of a sulfite source, the sulfite source being present in an amount to provide 0.02 to 0.6 mole sulfite per mole of phenol and wherein a first portion of formaldehyde, sufficient to establish a molar ratio of formaldehyde to phenol component of above about 0.2:1 but less than a molar excess of formaldehyde, is reacted with phenol in the presence of the sulfite source and then an additional portion of formaldehyde is added to establish the molar excess of formaldehyde for further reaction.