We have put together a list of kosher grocery stores and Delis.
Except for these, you can also find kosher products in ordinary stores. For example, Kosher wine and could be found in Karstadt department store, and Matzot at KaDeWe and Galeria Kaufhof. However, the product range is not in the rate and the comfort you might be used to in other countries. Some products maybe kosher but it is not indicated on the German package.
The best thing would be to buy/download the booklet “Rabbi Ist Das Koscher”, which indicates Kaschruth regarding all components in food products.
Train: U Bernauer Strasse
Open Monday-Thursday 8:00-19:00, Friday 9:00-18:00