According to Halacha, is one allowed to drink beer made with Chadash grain (does beer need to be Yashan)? Let’s assume for example this is from a Jewish farmer in Israel and you know it was planted at a point which would make it Chadash, theoretically would it just be a prohibition on eating it as bread and would it be permissible to drink it as beer or no?
It would be prohibited. The Shach Y”D 293:6 says ע"כ ובס' לח"מ סוף מסכת תרומות האריך למצוא היתר על שכר שעורים הנעשה מחדש מטעם שהמשקה היוצא מהן מותר וצריך להתיישב בדבר כי מתשובת הרא"ש ריש כלל ב' ומתרומות הדשן הנ"ל ומשאר פוסקים משמע שאסור loosely translated the above is trying to find a leniency for those who drink beer from chodosh but the conclusion is that is difficult to find one.
The argument behind the leniency is that the liquid derivate of the grain is not what the Torah prohibited as Chodosh. There is further discussion in the Poskim but the general consensus is that beer or other liquid would be like any other Chodosh and prohibited .