is generally manufactured in a batch process but can also be continuously produced by reacting formaldehyde with in an aqueous Ca(OH)₂ or NaOH solution at 15-45 °C. In the first step, a threefold mixed aldolization is followed by a Cannizzaro reaction, i. e., reduction of trimethylol acetaldehyde with formaldehyde and formation of formic acid as a coproduct:

Theoretically, four moles formaldehyde are necessary per mole acetaldehyde. In practice, up to a fourfold excess of formaldehyde is used to limit the formation of dipentaerythritol, the monoether of pentaerythritol [(HOCH₂)₃C-CH₂]₂O.

After neutralizing the excess Ca(OH)₂ with HCOOH the processing of the reaction mixture is done by stepwise concentration and fractional crystallization of pentaerythritol.

The analytically proven selectivity of about 91% (based on CH₃CHO) in the crude product is in practice seldom achieved because the isolation involves high losses.