When did the hamm's brewing company change the name on there bottles from hamm to hamm's?

I had not known or heard of a grammatical change to the brand name. It would have been before 1895 as I have an advertisement with the Hamm's Excelsior beer name. This is one year after the new brewery was finished in September 1894. So prior to the newly Incorporated brewery (1896) name "Hamm's" Theo. Hamm Excelsior brewery/beer was its name. But I have no reference to Theo Hamm being on the product label but only the brewery. However, some adds did carry his name with the beer along with the Pilsner and Culmbacher beers. So at best I would say it was, if at anytime, 18951896.