What does acidify mean?
The definition of acidify
A*cid”i*fy, v. t.
[imp. & p. p. Acidified; p. pr. & vb. n.Acidifying.]
Etym: [L. acidus sour, acid + -fy: cf. F. acidifier.]

1 To make acid; to convert into an acid; as, to acidify sugar.
2 To sour; to imbitter. His thin existence all acidified into rage. Carlyle.