I have a chronic sinus problem which means my voice will never go where I want it to be. Generally I manage okay unless I am singing hymns. For some reason there is something in a lot of hymns that set off my coughing and tickly throat. A certain pitch I obviously never read when singing folk songs. It's quite odd

My ENT specialist said I should stay clear of coffee as it dries you out a lot.

Hydration seems to be the best advise and help. Water does help a lot I have found.

mp