We love these. I have always recommecned to steer clear from square jars or bottles because the corners are weak spots and pressure from the gases can cause explosions.. but these are thick and solid and they also have the swing top which will open before anything explodes. 

If you are buying the Kilner continuous brew jar - which is 2 litres - 2 of these bottles will be perfect to bottle your brew each time leaving a small amount back as to feed the next batch. 

Comes in a cute pair of 2 bottles.