Praise be to Allah.
It was narrated by Muslim in his Saheeh (2051), and by at-Tirmidhi (1840) and Ibn Maajah (3316), from ‘Aa’ishah (may Allah be pleased with her), that the Prophet (blessings and peace of Allah be upon him) said: “What a good condiment vinegar is.”
Al-Kh attaabi said in his commentary on the hadith: What these words point to is moderation in eating and refraining from overindulgence in food. It is as if he was saying: Use as condiments vinegar and the like, which are inexpensive and are not difficult to obtain, and do not expend too much effort in pursuit of fine food, for indulging in desires spoils one’s religious commitment and makes the body sick.
End quote from Ma‘aalim as-Sunan (4/254)
Vinegar may be made from things other than wine. It says in al-Insaaf by al-Mirdaawi (1/320): Permissible vinegar is made by adding vinegar to the grapes or to the juice before they ferment, so that they will not ferment. This was stated by a number of scholars. End quote.
In Mataalib Ooli an-Nuha (1/230) it says: Permissible vinegar is made by adding vinegar to the grapes or to the juice before they ferment, before three days and nights have past, so that they will not ferment. This was narrated by a number of scholars from Ahmad. End quote.
The scholars have stated that the vinegar referred to in the hadith quoted above is that which is not derived from wine. It says in Tuhfat al-Ahwadhi (4/399): With regard to the hadith “What a good condiment vinegar is”, what is meant by vinegar here is vinegar that is not produced from wine, so as to reconcile between the hadiths. End quote.
If the vinegar was manufactured from something other than wine, it is permissible, and there is no scholarly difference of opinion concerning that. This is what was stated by the scholars of the Standing Committee when they said: If the vinegar was not originally wine, then there is no dispute that it is permissible, because any juice that turns acidic is called vinegar (khall),
End quote from Fataawa al-Lajnah ad-Daa’imah (fatwa no. 3429)
If wine turns to vinegar by itself, then it becomes pure and permissible.
It says in al-Insaaf by al-Mirdaawi (1/319): The correct view is that if wine turns into vinegar by itself, it becomes completely pure. This was stated (by the scholars) and is the view of the majority; many of them were certain of it. End quote.
With regard to treating wine so that it becomes vinegar, there was a dispute among the scholars with regard to that. Shaykh al-Islam Ibn Taymiyah referred to this dispute when he said:
As for turning wine into vinegar, there is a difference of opinion concerning it. It was said that it is permissible to turn wine into vinegar, as was narrated from Abu Haneefah; it was said that it is not permissible, but if it is turned into vinegar it becomes pure, as was narrated from Maalik; and it was said that it is permissible to move it from the sun to the shade, and to remove the cover from it, and so on, without adding anything to it, as is the view of ash-Shaafa‘i and Ahmad; it was said that it is not permissible at all, as was the view of some of the companions of ash-Shaafa‘i and Ahmad, and this is the correct view, because it was proven from the Prophet (blessings and peace of Allah be upon him) that he was asked about wine belonging to some orphans, and he ordered that it should be poured away. It was said to him: They are poor. He said: “Allah will enrich them from His bounty.” When he ordered that it should be poured away and forbade them to turn it into vinegar, it was obligatory to obey him with regard to his instructions and prohibitions. So it is obligatory to pour wine away and not make it into vinegar. This was despite the fact that they were orphans and despite the fact that that wine had been acquired before the prohibition on wine was introduced, so they were not sinning.
End quote from Majmoo‘ al-Fataawa (21/483)
Based on that, it is not permissible to turn wine into vinegar, because of the evidence to that effect in the saheeh hadiths.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) favoured the view that if wine belonging to those who believe it is permissible, such as ahl adh-dhimmah, has turned into vinegar, or it has been turned into vinegar by Muslim who believe that it is permissible to do so, then in that case it becomes vinegar and it is permissible to use it.
He (may Allah have mercy on him) said:
The well-known view is that if it turns into vinegar it does not become pure, even if its intoxicating strength has disappeared, because the disappearance of the intoxicating effect has been brought about by doing something that is prohibited, so it does not become permissible. Some of the scholars said that it does become pure and thus becomes permissible, even though the action is prohibited. They explained that by noting that the reason why it is impure is because of its intoxicating effect, and the intoxicating effect has disappeared, so it has become permissible.
Others said that if it was turned into vinegar by one who believes that alcohol is permissible, such as the People of the book – the Jews and Christians – it is permissible and has become pure. If it was turned into vinegar by one for whom alcohol is not permissible, then it is haraam and impure. This is the most correct view. Based on this, vinegar that comes from the Jews and Christians is halaal and pure, because they did that on the basis of their belief that it is permissible.
End quote from ash-Sharh al-Mumti‘ (1/433)
He also said:
But if it was turned into vinegar by someone who believes that it is permissible to turn it into vinegar, whether he is a Muslim or otherwise, is it permissible?
The correct view is that it is permissible, because it turned into vinegar in a permissible way, so it is permissible. Based on that, the vinegar that is imported from non-Muslim countries is permissible for the Muslims, even if it was turned into vinegar by human action, because it was turned into vinegar by human action on the part of one who believes that it is permissible.
End quote from ash-Sharh al-Mumti‘ (10/182)
And Allah knows best.