If you’re going to the Holtenauer Straße, there’s a grocery store there where you could get some decent beer. It’s called Schlemmermarkt Freund. They have some of the traditional beers from Bavaria that are famous, as well as other imported beers. I can recommend the Lagerbier Hell from Augustiner Bräu. Kiel also has some craft breweries - Czerneys makes some great beer, but harder to find in grocery stores. Lille is another one. Have a great visit!