Dumping Charcoal in my Garden

Cathy2 wrote:When I used to be a Master Gardner with U of I Extension, we did not recommend people throwing ash into their gardens. It wasn't going to contribute a thing and it would raise the pH, which wasn't desirable. If you have charcoal briquette ash, then it is not recommended due to the chemicals used to bind the briquettes. I toss my ashes into the garbage.

I wouldn't think any one here is using briquettes.

Question: does ash have the same chemical composition as charcoal? I don't think it does. I was putting basically chunks of uncombusted hardwood charcoal into the garden.