How do I find out why steamers sometimes have titanium, and which ones, if so? Also, why is it there in the first place?
If you mean metallic titanium - very unlikely. If you mean titanium compounds like the oxides - it is very likely. Titanium oxides are used in nearly all modern paints. I expect a fused ceramic coating is equally likely to contain titanium compounds. The people that write the info on the products are liberal arts majors and would not know titanium if it bit them. Metallic titanium would be easy enough to identify ; First is it magnetic ? If " yes" - not Ti. Does it feel "cold" ( assuming it is around 75 F), if "yes" - not Ti ( aluminum feels cold because of high conductivity) . Does it feel "heavy/dense ? If "yes" - not Ti ( stainless is about 50 % more dense than Ti). As these are relatively subjective tests ,it would be good to practice on known aluminum and stainless equipment first. If necessary, grinding wheel spark test; aluminum - no spark . stainless - limited orange/red sparks, Ti -bright white sparks.
As with all internet information, take this article with healthy skepticism, but it gives a summary:
To cherry pick, Titanium is used particularly in some current non-stick applications because it is strong, very strong, light, readily available (titanium is a fairly common element on earth. For durability is classified as self-healing because it forms a titanium-oxide surface that mostly prevents further degrading and when scratched will simply reform this film over time. It is considered non-toxic, mostly non-reactive to acids and does not flavor foods.
Note, that some applications that use titanium only as a coating or reinforcement, thought the titanium is considered safe by authorities, not all the bonding agents and media are equally safe so it is generally recommended to purchase such items through reputable and known sources of reasonable quality.
You will find sources that dispute all of the safety claims of course and are free to believe the sources you wish. In general, we do not debate such issues, rather we quote authorities that are responsible for testing and evaluation such as the USDA and equivalents in other jurisdictions, and they have apporoved titanium as safe.