this isn't quite round but could work?
64oz Clear Wide-mouth Glass Jar, BPA free Food Grade w/White Metal Lid (Half Gallon); 2 Quart Jar to Make Greek Yogurt/Kefir or Pickles https://www.amazon.com/dp/B01FMVSXHS/ref=cm_sw_r_cp_apa_i_5etlDb0QH3R41
It doesn't look like you're going to get a good seal around whatever you're using as a brewing vessel. Look on Amazon or go to a thrift store and find one that has a smooth recessed lid (like this but ditch the metal cap.
Yeah I did the same thing - the consistency/taste might suck but my priorities are nutritional value / convenience. I plan to fill up 7 of these every Sunday and always have two in the fridge, maybe shake em up before consumption.