"A beverage made by boiling ale with spice and sugar, and sops of bread". Known from 'A Dictionary of obsolete and provincial English' by Thomas Wright (Wright 1857)
The 1616 booklet 'Rules and Good Instructions to be observed Against the Plague' gives its Sixth Rule to "comfort the stomach with an aleberry made of cloves, mace, nutmegs and such like".
cf; Drinkmeat., Ale Gruel