Praise be to Allah.
The word khamr refers to all kinds of intoxicating drinks, whether it existed in the past or exists at present or will exist in the future, and whether the drink is made from grapes, barley, dates, corn or anything else.
That is indicated by the words of the Prophet (blessings and peace of Allah be upon him): “Every intoxicant is khamr and every khamr is haraam.” Narrated by Muslim, 2003
Khamr is a word that applies to any kind of drink that causes intoxication.
See: Ma‘aalim as-Sunan by al-Khattaabi, 4/264
Based on that, any drink that does not cause intoxication is not called khamr and it is not deemed to be haraam. But it is essential to make certain that this drink does not cause intoxication. It is often said that some drinks do not cause intoxication, then that turns out not to be so in reality.
Al-Haafiz said: The ruling is connected to the reason, and the reason for the prohibition of khamr is intoxication; whenever there is intoxication the prohibition applies.
End quote from Fath al-Baari, 10/56
It is not permissible to treat khamr in order to remove the alcohol from it; this is like what the scholars said about the prohibition on turning khamr into vinegar.
That is because we are commanded to avoid khamr, as Allah, may He be exalted, says (interpretation of the meaning):
“O you who believe! Intoxicants (all kinds of alcoholic drinks), gambling, Al-Ansab (stone altars for sacrifices to idols), and Al-Azlam (arrows for seeking luck or decision) are an abomination of Shaitan’s (Satan) handiwork. So avoid (strictly all) that (abomination) in order that you may be successful.”
Avoiding something means keeping far away from it, so that it is not near you.
End quote from Adwa’ al-Bayaan, 3/33
Treating it to remove the alcohol from it is contrary to avoiding it.
Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him) said: Because keeping khamr is haraam; if a person is keeping it to turn it into vinegar, he has committed a haraam action.
End quote from Majmoo‘ al-Fataawa, 21/503
It is proven from the Prophet (blessings and peace of Allah be upon him) that it is forbidden to turn khamr into vinegar. Muslim (1983) narrated from Anas ibn Maalik (may Allah be pleased with him) that the Prophet (blessings and peace of Allah be upon him) was asked about wine that is made into vinegar. He said: “No.”
According to a version narrated by Abu Dawood (3675), Abu Talhah asked the Prophet (blessings and peace of Allah be upon him) about some orphans who inherited some wine. He said: “Pour it away.” He said: Can I turn it into vinegar? He said: “No.”
Classed as saheeh by an-Nawawi in al-Majmoo‘, 9/233; Ibn al-Mulqin in al-Badr al-Muneer, 6/630; and Shaykh al-Albaani in Saheeh Abi Dawood.
This prohibition implies that it is haraam; if it were possible to benefit from khamr or to turn it into something from which people could benefit, it would not be permissible to pour it away; rather the Prophet (blessings and peace of Allah be upon him) would have instructed him to do that, especially since it belonged to orphans and it is haraam to squander their wealth.
In Fataawa al-Lajnah ad-Daa’imah (22/92) it says: Khamr must be poured away… because the Prophet (blessings and peace of Allah be upon him) issued orders to that effect when the two verses concerning the prohibition of alcohol were revealed. It is haraam to keep it and make use of it as it is, and it is haraam to turn it into something other than khamr by turning it into vinegar or turning part of it into vinegar or extracting the alcohol from it, or to mix it with something else that one wants to benefit from, because the Prophet (blessings and peace of Allah be upon him) forbade turning khamr into alcohol in order to block the means that may lead to evil and to prevent any possibility of people going back to making it and using it. End quote.
See also the answer to question no. 14276
To sum up: treating khamr to remove the alcohol from it is haraam, and is not permissible.
But if that has been done, is it permissible for a person to drink it, seeing that it is free of the intoxicants which are the reason for the prohibition, or not?
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said:
The well known view is that if it has been turned into vinegar, it does not become pure (taahir), even if the intoxicating effect has been removed, because removing the intoxicants is done by means of doing something haraam, so it is still haraam.
Some of the scholars said that it does become pure and therefore becomes permissible, even though the action is haraam. The reason they give for that is that the reason why it is impure (najis) is because it causes intoxication, and the intoxicants have been removed, so it is halaal.
Others said that if it was turned into vinegar by people who believe that khamr is permissible, such as the People of the Book, the Jews and Christians, then it is permissible and becomes pure (taahir); if it was turned into vinegar by people for whom it is not permissible, then it is still haraam and impure (najis).
This opinion is most likely to be correct. According to this view, the vinegar that comes from the Jews and Christians is halaal and pure (taahir) because they did that on the basis that they believe it is permissible.
End quote from ash-Sharh al-Mumti‘, 1/250
He also said: But if it was turned into vinegar by someone who believes that turning it into vinegar is permissible, whether he is a Muslim or a non-Muslim, is it halaal?
The correct answer is that it is halaal, because it was turned into vinegar in a permissible manner, so it became permissible. Based on that, the vinegar that is imported from non-Muslim countries is halaal for Muslims, even if it was produced by means of human actions, because it was turned into vinegar by the actions of a human who believed it to be permissible.
End quote from ash-Sharh al-Mumti‘, 10/53
To sum up:
If it is clear that this drink is free of alcohol, there is nothing wrong with drinking it. Similarly, if treatment of khamr to remove alcohol from it was done by people who believe it is permissible to do that, then it is permissible to drink it. However we should point out that this treatment is something that is haraam for the Muslim to do according to the most correct opinion.
And Allah knows best.