Kosher Craft Beer

again, for clarity's sake, if the whole brewery operates under the bavarian purity law, and only makes beers with those four ingredients, then it would be fine.

I've yet to find a (good) craft brewery that prides themselves on following the reinheitsgebot tradition to the letter of the law

 

if you are referring to the six pointed brewers star which looks like a star of david, that is not a kosher symbol

 

Almost all beers are made using one of the many types of beer yeasts. Biere De Champagne or Biere Brut quite obviously use champagne yeast for primary fermentation (could be some just carbonate highly, but not sure). Also, some use champagne yeast for bottle conditioning, again usually obvious, but not always. I, personally, wont drink any cider without a hechsher, and of course follow the orthodox standards for all wines.

Its also worth noting that most homebrewing yeasts (and many malts), which are often also used commercially, are actually kosher supervised and certified kosher. (I have all of the documentation if you have any specific questions) This includes a few different types of champagne yeast.

heres a pic of a common one with the hechsher of Adas Yereim of Paris actually visible on the bottom corner of the packet:

 

As far as i know, the rules of mevushal wine only applies to grape products. Beer and cider made with wine yeast would not fall under any prohibitions of who can handle it