We forwarded the above question to the offices of some of the grand jurists and the answers which we have received are as under:
Office of Grand Ayatollah Khamenei (may Allah grant him long life):
Generally speaking, the alcohol which is not determined whether or not it is originally intoxicating or not, is ritually clean and is treated as such. There is no problem in using the liquids which contain alcohol and if one doubts whether the alcohol is intoxicating or not, it is treated as clean. If gelatin comes in halal and haram type and you do not know whether it is of the halal type or of the haram type, it is treated as halal and it is permissible to use it.
Office of Grand Ayatollah Sistani (may Allah grant him long life):
It is permissible to eat gelatin if one doubts whether it has been extracted from an animal or vegetable. All kinds of alcohol whether derived from wood or other sources are pure (tãhir). Therefore, the food in whose preparation alcohol was used is tãhir except for when it causes drunkenness, in which case, the ruling which will apply to it would be different; it would be haram to use it. God knows best.
Office of Grand Ayatollah Makarem Shirazi (may Allah grant him long life):
Yes, it is not permissible.
The answer given to the foregoing question by Ayatollah Mahdi Hadavi Tehrani (may Allah grant him long life) is as under:
If gelatin is derived from vegetable for an animal which has been slaughtered according to Islamic law, it is halal and ritually pure. If it is likely to have been derived from halal source, it will be pure and if it is probable that it has been derived from vegetable it would be also halal to eat.
If a chemical change occurs in the original ingredients during the process of manufacturing the gelatin, it is clean and there is no problem at all in eating it even if the original ingredient may have been pork or meat of an animal which has not been slaughtered according to Islamic laws.
Alcohol is pure but it is not permissible to consume it. In case the amount of alcohol existing in food is so minute that the food is considered by the wise as having no alcohol, it is halal to eat. In case one doubts about it, it is treated as permissible to eat.
For further information in this regard, refer to the following indexes:
1. Index: The Islamic law about the permissibility of alcohol, question No.2501 site: 2631).