People have inquired about Vassar's beer recipe from time to time. There is no direct reference to the beer recipe in the Matthew Vassar Papers register,
http://specialcollections.vassar.edu/findingaids/vassar_matthew.html , though there are many letters about the business of the brewery (the purchase of ingredients, orders from patrons, comments/complaints about the product, etc). This last semester, a student actually wrote his thesis on Vassar's brewery in Poughkeepsie using the letters, and as part of his work went through his papers quite closely. I was able to contact him on this question and here is what he responded:
"I never found an actual recipe for his beer, as the proportions were always changing and his letters focus more on the growth of the business and dealings in Albany and New York, while I'm sure the recipe was simply discussed at the brewery. Folder 22, during the late 1840s, has some of his commentary on the failings of the beer and suggestions to add honey and other ingredients (22.670 and thereabouts)."
Also, according to the Vassar College Encyclopedia entry on campus traditions,
http://vcencyclopedia.vassar.edu/traditions/index.html , the second paragraph says they brewed beer from a recipe *similar* to M. Vassar's (emphasis mine) in 1992. So it seems that even then they were not working from the original recipe itself.
