Presumably the English knew that there existed a compound common to fermented or distilled liquids that caused intoxication, but before they had the word alcohol, what did they call this chemical compound?
Here is an interesting article on the etymology of alcohol. It claims that in Middle English, they callled intoxicants licur (which we know as liquor) - which means, well, liquid - and bouse (which we know as booze), which was the word for "beer", and applied in the general to drink, especially in verb form (bousen).
Origin: 1200–50; Middle English (noun) < Latin spīritus orig., a breathing, equivalent to spīri-, combining form representing spīrāre to breathe + -tus suffix of v. action
Ether is another term to consider, since the language of your question seems to lean in the scientific direction:
An organic compound in which two hydrocarbon groups are linked by an oxygen atom, having the general structure ROR', where R and R' are the two hydrocarbon groups. At room temperature, ethers are pleasant-smelling liquids resembling alcohols but less dense and less soluble in water.
In older scientific literature, ether had many different meanings and usages. See: The Composition and Structure of Ether:
The preparation of alcohol (spirit of wine, vinic alcohol, ethanol, ethyl alcohol) by fermentation dates to antiquity. Closely related to alcohol -- both through history and chemistry -- is ether (ethyl ether, diethyl ether) a compound obtained from alcohol by the action of oil of vitriol (sulfuric acid).
Or (if you're talking about liquor):
which is even earlier:
Alcohol is a later addition to the language:
an alcoholic liquor made by fermenting honey and water.
any of various nonalcoholic beverages.
Origin of mead
Before 900; Middle English mede, Old English medu, meodu; cognate with Dutch mee, German Met, Old Norse mjǫthr mead, Sanskrit madhu honey, Greek méthy wine
an alcoholic liquor or spirit distilled from molasses or some other fermented sugar-cane product.
Origin of rum: 1645-55; perhaps short for obsolete rumbullion, rumbustion, of obscure origin