I lot of things can dull your palate.
Hot food/drink, cold food/drink, spicy food, infections, dry mouth, smoking and extremely sour foods.
Dehydration can cause a dry mouth. Make sure you are drinking enough water.

https://ucanquit2.org/HowToQuit/Reso...QuitFoods.aspx

Dairy, Fruits and Veggies May Help Smokers Quit - Duke Medicine