Notes on Silica Gel.

I went down a lot of little cul-de-sacs while writing the silica gel explainer I published on Monday. Many of them were indispensable to my overall understanding of the topic, but simply didn't fit the piece's narrative structure, or the practical limits on its length. So as I clear my tabs out this morning, here's some errata—pithy as heck, and worth following up on in your own time—on silica gel.

• While silica gel desiccant packets are not safe to eat, amorphous silicates are generally considered non-toxic. W.R. Grace advertised colloidal silica gel as a toothpaste additive as early as 1930, and "hydrated silica" (typically precipitated) is commonly used in toothpaste for its polishing and thickening properties today. There does seem to be some concern about the presence of nanoscale particles in commercially-available silicate food additives: This 2023 FDA study, as well as this 2018 study by the European Food Safety Authority, both seem to suggest that silicon dioxide is generally safe to consume while voicing a need for further research on very small SiO2 particles.