Answered by Shaykh Abdul-Rahim Reasat
Question: Is my fast invalid if I taste something in my mouth?
Answer: Wa ‘alaykum assalam wa rahmatullah wa barakatuh
I pray you are well.
Merely getting a taste of something in your mouth does not invalidate your fast. It has to pass down your throat to invalidate the fast. In these situations, you merely tasted something, and that does not affect the fast.
Unavoidable Substances
Steam, smoke from traffic, flour that disperses in the air, and similar substances which are hard to avoid do not invalidate the fast if they are inhaled with a valid excuse. It would be pretty difficult to cook or have a shower without having any of the streams enter one’s mouth or nose, so it is excused. (Shurunbulali, Maraqi al Salah; Ibn Abidin, Radd al Muhtar)
Learn for Confidence
The Messenger of Allah, Allah bless him and grant him peace, said, “Indeed [the practice of] the din is eased itself, and no one makes it hard on themselves except that it overwhelms them.” (Bukhari) This is a central hadith, and it clearly shows that following the sunna should make religious practice easy.
One of the ways to make things easy is to learn them properly from an experienced and qualified teacher. This goes a long way in alleviating unnecessary worries. Please register for a course, and actively take part in it to maximize the benefit you get. Registration will open in a week or so.
May Allah grant you the best of both worlds.
[Shaykh] Abdul-Rahim Reasat
Checked and Approved by Shaykh Faraz Rabbani