There is no harm in tasting the food if there is a need for it. This is done by the person [tasked with iftar preparation] placing it on the tip of his tongue so he may know its sweetness and saltiness; however, he should not swallow any of it. Rather, he should spit it out or expel it from his mouth and his fast will not be corrupted by that.
But we should remember that it is disliked to taste food unnecessarily because this carries the risk of the fast being broken. An example of cases where it is necessary to taste food includes a mother chewing food for an infant when she has no other way to feed it.
(Fasting According to the Sunnah, Muhammad Zulfiqar, The Ruling on Tasting Food)
وَبَلَّ ابْنُ عُمَرَ رَضِيَ اللَّهُ عَنْهُمَا ثَوْبًا، فَأَلْقَاهُ عَلَيْهِ، وَهُوَ صَائِمٌ. وَدَخَلَ الشَّعْبِيُّ الْحَمَّامَ وَهُوَ صَائِمٌ.
وَقَالَ ابْنُ عَبَّاسٍ لاَ بَأْسَ أَنْ يَتَطَعَّمَ الْقِدْرَ، أَوِ الشَّيْءَ.
وَقَالَ الْحَسَنُ لاَ بَأْسَ بِالْمَضْمَضَةِ وَالتَّبَرُّدِ لِلصَّائِمِ.
وَقَالَ ابْنُ مَسْعُودٍ إِذَا كَانَ صَوْمُ أَحَدِكُمْ فَلْيُصْبِحْ دَهِينًا مُتَرَجِّلاً.
وَقَالَ أَنَسٌ إِنَّ لِي أَبْزَنَ أَتَقَحَّمُ فِيهِ وَأَنَا صَائِمٌ. وَيُذْكَرُ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَّهُ اسْتَاكَ وَهُوَ صَائِمٌ.
وَقَالَ ابْنُ عُمَرَ يَسْتَاكُ أَوَّلَ النَّهَارِ وَآخِرَهُ، وَلاَ يَبْلَعُ رِيقَهُ.
وَقَالَ عَطَاءٌ إِنِ ازْدَرَدَ رِيقَهُ لاَ أَقُولُ يُفْطِرُ.
وَقَالَ ابْنُ سِيرِينَ لاَ بَأْسَ بِالسِّوَاكِ الرَّطْبِ. قِيلَ لَهُ طَعْمٌ. قَالَ وَالْمَاءُ لَهُ طَعْمٌ، وَأَنْتَ تُمَضْمِضُ بِهِ. وَلَمْ يَرَ أَنَسٌ
Ibn ‘Umar moistened a garment and put it on while he was fasting. Ash-Sha’bi went into the hammam (olden days bathroom for shower).
Ibn ‘Abbas said, “There is no harm in tasting the pot or something.”
Al-Hasan said, “There is no harm in someone fasting rinsing out his mouth and cooling himself.”
Ibn Mas`ud said, “When one of you is fasting, morning should find him with his hair oiled and combed.”
Anas said, “I had a (water) tub in which I could sit while I was fasting.”
It is mentioned that the Prophet ﷺ used to clean his teeth [with siwak] while he was fasting.
Ibn ‘Umar said, “He cleaned his teeth at the beginning and end of the day without swallowing his saliva.”
‘Ata’ said, “I do not say that saliva breaks the fast.”
Ibn Sirin said, “There is no harm in using a moist siwak.” He was told that it had a taste and replied, “Water has a taste and yet you rinse your mouth out with it.”
Anas, al-Hasan, and Ibrahim did not see any harm in someone fasting using kohl (a preparation used especially in Arabia and Egypt to darken the edges of the eyelids).
(Saheeh al-Bukhari, Book of Fasting, Chapter 25: Taking a bath by a person observing Saum)
NOTE: This is a Mu’allaq (suspended/hanging) Hadith of Bukhari, but it is connected along with Sahih Ibn Shaiba’ and Bayhaqi and the chain goes on..it makes it Sahih.
Abdullah bin Amir bin Rabi’ah narrated from his father who said: “I saw the Prophet – (a number of times) such that I was not able to count – using the Siwak while he was fasting.”
“I prefer that he should avoid tasting food, but if he does that it will not affect him and there is nothing wrong with that.” [Ref: Al-Mughni, 4/359]
Shaykh al-Islam Ibn Taymiyah:
“Tasting food is makrooh (i.e., a disliked/offensive act) if there is no need to do that, but it does not break the fast.”
[Ref: al-Fataawa al-Kubra 4/474]
Imam al-Nawawi ash-shaf`i (the teacher of Ibn taymiyyah who died in 728 A.H) answers some questions about fasting:
Question: Does the fast break if one: Tastes the food without swallowing it? Bite bread without swallowing it? Gather saliva in the mouth to swallow it later? Unintentionally open the mouth and a fly flies into it? If one harvest oats or rye and dust falls into the mouth? Water enters the stomach while he gargles or if he blows out water from the nose without exaggeration?
Answer: “None of these acts break the fast.” (Fatâwâ al-Imâm an-Nawawî, p. 55)
Shaykh Ibn ‘Uthaymeen:
“The fast is not invalidated by tasting food so long as one does not swallow it, but you should not do that unless there is a need for it; in that case if a little of it reaches your stomach by accident your fast is not invalidated.”
(Fataawa al-Siyaam p. 356)
Shaykh Ibn ‘Uthaymeen:
“It is makrooh to taste food such as dates, bread, and soup, unless there is a need to do that, in which case it is fine. The reason for that is that some of this food may go down into the stomach without a person realizing, so tasting this food exposes him to spoiling the fast. Also he may be desiring the food a great deal, so he tastes it in order to enjoy it, and he may swallow it, then some of it goes down into his stomach. Examples of necessity are when a cook needs to see how salty or sweet the food is, and so on.”
(al-Sharh al-Mumti’ 3/261)