Sterilize the mason jar in a large pot of water by boiling it in water for five minutes. Keep warm. If you are using a mason jar lid, sterilize it by pouring boiling water over it in a bowl.
In a medium saucepan, add the water, vinegar, salt and sugar.
Bring everything to a boil in the saucepan and keep it bubbling on medium high for five minutes until the salt and sugar are dissolved.
Using tongs, remove the sterilized jar from the pot.
Add the chilli flakes, crushed garlic, dill flowers, and the beans to the jar.
Funnel the hot brine into the jar making sure that the beans are completely submerged.
Screw on the lid and allow to cool before transferring to the fridge.