Round them will be passed a cup of pure wine -- white, delicious to the drinkers. Neither will they have Ghawl from that nor will they suffer intoxication therefrom.
This is like the Ayah;
يَطُوفُ عَلَيْهِمْ وِلْدَنٌ مُّخَلَّدُونَ
بِأَكْوَابٍ وَأَبَارِيقَ وَكَأْسٍ مِّن مَّعِينٍ
لااَّ يُصَدَّعُونَ عَنْهَا وَلَا يُنزِفُونَ
Immortal boys will go around them (serving), with cups, and jugs, and a glass of flowing wine, from which they will get neither any aching of the head nor any intoxication. (56;17-19)
Allah refined the wine of Paradise from the bad effects of the wine of this world, which causes headaches and stomach aches -- which is the meaning of Ghawl -- causing people to lose their minds completely.
So He says here;
يُطَافُ عَلَيْهِم بِكَأْسٍ مِن مَّعِينٍ
Round them will be passed a cup of pure wine,
meaning, wine from a flowing stream which they do not fear will ever be cut off or cease.
Malik narrated that Zayd bin Aslam said,
"White flowing wine," meaning, with a bright, shining color, unlike the wine of this earth with its ugly, repulsive colors of red, black, yellow and turbid shades, and other features which are repugnant to anyone of a sound nature.
لَذَّةٍ لِّلشَّارِبِينَ
(delicious to the drinkers).
means, its taste will be as good as its color, and a good taste indicates that it has a good smell, unlike the wine of this world.
لَاا فِيهَا غَوْلٌ
Neither will they have Ghawl from that,
means, it will not have any effects on them such as causing stomach aches.
This was the view of Ibn Abbas, may Allah be pleased with him, Mujahid, Qatadah and Ibn Zayd.
This is unlike the wine of this world, which causes colic and so on, because it is too watery.
وَلَا هُمْ عَنْهَا يُنزَفُونَ
nor will they suffer intoxication therefrom.
Mujahid said,
"It will not cause them to lose their minds."
This was also the view of Ibn Abbas, Muhammad bin Ka`b, Al-Hasan. `Ata' bin Abi Muslim Al-Khurasani, As-Suddi and others.
Ad-Dahhak reported that Ibn Abbas said,
"Wine causes four things;intoxication, headache, vomiting and urine."
So, when Allah mentions the wine of Paradise, He states that it is free of these characteristics, as mentioned in Surah As-Saffat